space food research paper

Recent developments in space food for exploration missions: A review

Affiliations.

• 1 Department of Post-Harvest Engineering and Technology, Faculty of Agriculture, Aligarh Muslim University, Aligarh, 202002, India. Electronic address: [email protected].
• 2 Department of Food Engineering and Technology, Institute of Engineering and Technology, Bundelkhand University, Jhansi, 284128, India.
• 3 Department of Post-Harvest Engineering and Technology, Faculty of Agriculture, Aligarh Muslim University, Aligarh, 202002, India.
• 4 Department of Chemistry, Government Degree College Pulwama, Jammu and Kashmir, 192301, India.
• PMID: 36682821
• DOI: 10.1016/j.lssr.2022.09.007

Food and nutrition have greatly influenced the effectiveness of space exploration missions. With the development of technology, attention is now being paid more and more to preparing food for the microgravity environment, taking into account factors like nutrient density, shelf life, optimized packaging, preservations, innovations, challenges, and applications. The spectrum of food products is designed to meet the balanced nutritional requirements, reduce hazards encountered by astronauts, and utilize space in explorers during space missions. For the long duration of space missions and, consequently, for human permanence in space, it is crucial to provide humans with an adequate supply of fresh food to meet their nutritional needs. By doing this, astronauts could reduce the health risks associated with psychological stress, microgravity, and radiation exposure from space. Maintaining astronauts' health, happiness, and vitality during long-duration human-crewed missions has recently emerged as an essential and critical research area. The food they eat appears to be an important factor. For short-term space missions, astronauts' food could be brought from earth. Still, for long-term space missions to the Moon, Mars, and other distant missions, which are the current research destinations, they must find a way to eat, such as by cultivating plants or finding other means of survival. Scientists and researchers are attempting to develop novel food production technologies or systems that require minimal inputs while maximizing safe, nutritionally balanced, and delicious food outputs for long-duration space missions that could benefit people on earth. This review summarizes various aspects of space food, including evolution, innovations, technological advancements to prolong shelf life, and astronauts' problems. It also involves current research, including space foods like 3D printing and space farming for a long-term space mission.

Keywords: 3D printing; Astronauts; Innovations; Microgravity; Space farming; Space food.

Copyright © 2022. Published by Elsevier B.V.

Publication types

• Space Flight*
• Weightlessness*

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Space Food and Nutrition in a Long Term Manned Mission

• Original Paper
• Open access
• Published: 25 August 2018
• Volume 1 , pages 1–21, ( 2018 )

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• Funmilola Adebisi Oluwafemi   ORCID: orcid.org/0000-0001-7575-9992 1 ,
• Andrea De La Torre 2 ,
• Esther Morayo Afolayan 3 ,
• Bolanle Magret Olalekan-Ajayi 4 ,
• Bal Dhital 5 ,
• Jose G. Mora-Almanza 6 ,
• George Potrivitu 4 ,
• Jessica Creech 4 &
• Aureliano Rivolta 7  

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A Correction to this article was published on 19 December 2018

This article has been updated

Fulfillment of space exploration mission is key, but much more important are the lives of the explorers. Keeping the astronauts alive, jolly and healthy for long term manned mission has recently being a major and important research area. A major contribution seems to be the food they eat. For short term space manned missions, astronauts food could be taken along with them from Earth, but for manned missions to the Moon, Mars and Venus which are the current research destinations for long term space missions, they must find a means for their nutrition such as growing plants and finding any other alternatives for their survival. As most of these proposed missions have being designed to be one-way missions whereby the astronauts will not come back to the Earth. Good food and nutrition for astronauts help to keep their psychology and physiology in good shape. In this paper, solutions will be made on the various alternatives for feeding astronauts in the long term missions to various celestial bodies: Moon, Mars and Venus, where the atmosphere, gravity, soil, radiation and other conditions vary from one to the other and may not support germination, growth and development of plants. Therefore, review will be done on the following: having fore knowledge of how plants will grow on these celestial bodies by simulating their soils; using mathematical/theoretical models to get the growth rate of plants in relation to the gravity available on these celestial bodies using available data from terrestrial growth (1 g growth) and microgravity/microgravity simulations facilities; getting to know how the plants will be grown such as using greenhouse method as a result of the atmosphere and radiation in these celestial bodies; and other various alternatives for growing plants and having the astronauts well-nourished such as using aeroponics and hydroponics methods. A brief discussion will also be done on food choice for astronauts considering psychosocial and cultural factors.

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1 Introduction

There are cultural, scientific, and political imperatives that contribute to the drive to explore space. The cultural imperative is embodied in the innate need of humankind to extend its boundaries and move forward into new domains, in the process gaining a sense of progress and common accomplishment. This urge to explore and advance seems to flow from a survival instinct that is basic to the human species. The scientific imperative derives from humankind’s desire to understand its surroundings, whether to satisfy natural curiosity, gain material benefit, or dispel fear of the unknown. This may be another manifestation of the same fundamental characteristic of human nature, since scientific thought, observation and experimentation are well documented throughout recorded history. We now know that certain fundamental and compelling questions of our origins and destiny can only be answered by observing phenomena in deep space and by studying the environments of our solar system [ 1 ].

Some of these imperatives include: the prediction of United Nations that by 2050 the Earth’s human population will have grown from 7.6 billion to 9.8 billion and by 2100 to 11.2 billion [ 2 ]; the sustainability of world’s population, the growing pressures on the environment, global food supplies, and energy resources, humanity needs to start planning to leave the safety net of the Earth and look to the stars. Spreading out to one of our next door neighbors, such as the Moon or Mars [ 3 ]; in five billion years, our Sun will start to die, expanding as it enters its red giant phase. It will engulf Mercury, Venus, and, even if it does not swell enough to reach Earth, it will still boil off the oceans and heat the surface to temperatures that even the hardiest life forms could not survive. It is hoped that long before any of these natural or man-made terrestrial problems come to pass, humans would have chosen to leave Earth and move to Mars, the Moon or beyond [ 4 ]. “If we make it to Mars, we will have answered the question of whether humanity is fated to be a single-planet or multi-planet species”, Elon Musk [ 5 ] says.

There is this claim that, although the Moon is nearer, making access and communications easier, it is Mars that seems to have captured our imagination for a future human outpost. Much of this is inspired by evidence that it might have once been a world similar to the Earth. Mars is one of the few places in our solar system where life similar to Earth life may be able to survive. This makes it of particular interest to us, but it also makes it a location of special concern for human exploration. The picture of the solar system is seen in Fig.  1 .

The solar system

Space food is a variety of food products, specially created and processed for consumption by astronauts in outer space. As nutrition is the process of providing or obtaining the food necessary for health and growth, space nutrition is therefore, the process of providing or obtaining the food necessary for health and growth in space. Nutrition has played a critical role throughout the history of explorations, and space exploration is no exception. Space explorers have always had to face the problem of how to carry enough food for their journeys as adequate storage space has been a problem. Long-duration spaceflight will require the right amount of nutrient requirements for maintenance of health and protection against the effects of microgravity. Sustaining adequate nutrient intake during space flight is important not only to meet nutrient needs of astronauts but also to help counteract negative effects of space flight on the human body and to avoid deficiency diseases, i.e., food needs to be edible throughout the voyage, and it also needs to provide all the nutrients required to avoid diseases. For example, because of microgravity, astronauts lose calcium, nitrogen, and phosphorus. Therefore, these lost nutrients need to be gained back through food. Space foods usually have the following characteristics: nutritious, light weight, compact, easily digestible, palatable, physiologically appropriate, well packed, quick to serve, easy to clean-up, high acceptability with minimum preparation.

National Aeronautics and Space Administration (NASA) officials in turn are betting that high-tech 3D food printers, using nutrient-laden media as the base material, might help further the goal of eventually reaching Mars. 3D printing can be adjusted on the fly to address both flavor and nutritional demands. Potentially, it could be used to make freshly prepared food to the crew-member’s preferences, customize the foods, and add in specific nutrition over time. That was the idea, separated out ingredients can be taken that are highly stable and then, in a completely automated system, mixed and printed out [ 6 ].

Apart from the provision of required nutrients, space nutrition also has many other aspects of impact, including maintenance of endocrine, immune, and musculoskeletal systems. Nutrition and food science research overlap, with integral to many other aspects of space medicine and physiology including psychological health, sleep and circadian rhythmicity, taste and odor sensitivities, radiation exposure, body fluid shifts, and wound healing and to changes in the musculoskeletal, neurosensory, gastrointestinal, hematologic, and immunologic systems. Nutrient intake plays a fundamental role in health maintenance. Good food and nutrition for astronauts help to keep their psychology and physiology in good shape. Therefore, good meals for astronauts have psychosocial and physiology benefits.

Psychosocial and cultural factors are important aspects of nutrition for productive mission and crew morale. Therefore, research is also needed to be done more on this. Spaceflight is associated with many physiological changes, as a result of the microgravity environment, including space motion sickness, fluid shifts, congestion and altered taste and smell. The environment of the spacecraft (including the spacecraft cabin, radiation, lack of ultraviolet light exposure, carbonIVoxide exposure, and the spacesuit atmosphere) can affect nutrition and nutritional requirements for long-duration spaceflight [ 7 ]. At the required celestial mission station after the long spaceflight, there will also be challenges on the psychosocial and cultural factors of nutrition.

In this paper, solutions will be made on the various alternatives for feeding astronauts in the long term missions to various celestial bodies: Moon, Mars and Venus, where the atmosphere, gravity, soil, radiation, light and other conditions vary from one to the other and may not support germination, growth and development of plants.

2 Characteristics of Earth, Moon, Mars and Venus in Relation to Plant Growth

2.1 earth (control condition for planting).

Gravity is the force that attracts a body towards the centre of the Earth, or towards any other physical body having mass. Gravity is very important as it makes the Earth to retain its atmosphere. The gravity of the Earth is 9.807 m/s 2 . The atmosphere of Earth is the layer of gases, commonly known as air, which surrounds the planet Earth. The atmosphere of Earth protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night [ 8 ]. On the Earth the daylight available is adequate to grow plants. The availability of a significant atmosphere, and hence greenhouse warming, combined with Earth’s distance from the Sun, make Earth’s temperature good for plant growth. The atmosphere of Earth therefore makes it possible for lives survival.

Soil is the upper layer of Earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles. The most important benefits that the soil provides for the plants are: nutrients, moisture, and aeration and structure. Rich soil contains the primary plant nutrients of nitrogen, phosphorus and potassium along with a host of minor nutrients that help fuel plant growth. Decaying organic matter and minerals within the soil provide these nutrients. Soil that does not contain sufficient nutrients requires fertilizer to add the nutrients needed by the specific plants grown in the soil. Soil acidity, discovered by a pH test, also affects how well nutrients are available to plants. Most plants perform best in soil that has a pH level near neutral, or 6.0–7.0 pH, although some do best in soil with a higher or lower pH level.

Moisture affects the health of plants and soil. Most garden plants grow best when the soil remains evenly moist, but they do not tolerate soggy or wet conditions. Good soil drains excess water well without drying out too quickly. A soil rich in organic matter, either naturally or from compost amendments, provides drainage and moisture. Some soil contains heavy clay particles, which make it too wet, while other soil is sandy and drains too quickly.

Plant roots need access to oxygen in the soil to thrive, but the soil still must offer enough structure to support the roots. Wet or dense soil suffocates roots, and overly aerated soil gives roots nothing to grasp, making the plants easily uprooted. Turning the soil before planting helps incorporate oxygen into the soil, as does the addition of organic matter such as compost and peat. The largest particles in organic matter break up clay and sand in soil, providing more space for aeration between all of the particles in the soil [ 9 ]. Physical and atmospheric properties of the Earth are shown in Table  1 .

2.2 Soil of Mars, Moon and Venus

The surface and soil of a planetary body holds important clues about its habitability, both in its past and in its future. For example, examining soil features have helped scientists show that early Mars was probably wetter and warmer than it is currently. “Studying soils on our celestial neighbors’ means to individuate the sequence of environmental conditions that imposed the present characteristics to soils, thus helping reconstruct the general history of those bodies”. In 2008, NASA’s Phoenix Mars Lander performed the first wet chemistry experiment using Martian soil. Scientists who analyzed the data said the Red Planet appears to have environments more appropriate for sustaining life than what was expected, environments that could 1 day allow human visitors to grow crops. Researchers found traces of magnesium, sodium, potassium and chloride, and the data also revealed that the soil was alkaline (8 or 9), a finding that challenged a popular belief that the Martian surface was acidic. This type of information, obtained through soil analyses, becomes important in looking toward the future to determine which planet would be the best candidate for sustaining human colonies.

Certini and his colleague Riccardo Scalenghe from the University of Palermo, Italy, recently published a study in Planetary and Space Science that makes some encouraging claims. They say the surfaces of Venus, Mars and the Moon appear suitable for agriculture. On Venus, Mars and the Moon, weathering occurs in different ways. Venus has a dense atmosphere at a pressure that is 91 times the pressure found at sea level on Earth and composed mainly of carbonIVoxide and sulphuric acid droplets with some small amounts of water and oxygen. Mars is currently dominated by physical weathering caused by meteorite impacts and thermal variations rather than chemical processes. The red colour of the Martian soil comes from iron oxide (rust or hematite) in its soil [ 10 ] with pH of 8. On the moon, a layer of solid rock is covered by a layer of loose debris. The weathering processes seen on the Moon include changes created by meteorite impacts, deposition and chemical interactions caused by solar wind, which interacts with the surface directly. The Moon rather has lunar regolith. Regolith is inorganic and lies like a blanket over unfragmented rock. It is typically made up of material that is weathered away from the underlying rock. The soil is a zone of plant growth and is a thin layer of mineral matter that normally contains organic material and is capable of supporting living plants [ 11 ].

Some scientists, however, feel that weathering alone is not enough and that the presence of life is an intrinsic part of any soil. One of the primary uses of soil on another planet would be to use it for agriculture, to grow food and sustain any populations that may 1 day live on that planet. This is one of the biggest challenges needed to be solved to enable humans to live on another planet. Some scientists, however, are questioning whether soil is really a necessary condition for space farming [ 12 , 13 ]. The pictures of the Martian soil, Moon regolith and the Venus soil/regolith are seen in Figs.  2 , 3 and 4 .

Martian soil

Moon Regolith

Venus soil/Regolith

Mars is often seen as the next logical step in human exploration of the Solar System. This interest in Mars is linked with its resources and environment, which could help sustain long term human presence, and answer the crucial question, “Can life arise outside our planet?”. In the past, Mars presented environmental conditions that might have been able to support life as known on Earth, including liquid water and a dense atmosphere. However, the evolution of Mars has rendered its surface environment inhospitable for all currently known life forms. With this increased enthusiasm and excitement about mars mission, it is easy to disregard or forget the challenges and difficulties that such a feat entail. Even though more than 50 years have passed since mankind first ventured into space, the challenge of putting a man on Mars presents additional complications that the space industry has not faced before. The idea of a one-way mission (also known as “Mars to stay”) was first proposed in 1996 [ 14 ] and has, since then, led to a several subsequent proposals that first mission to Mars should be a settlement, not a visit [ 15 ]. Despite slight variations in the content of these proposals, they all rest on several common arguments: A one-way mission to Mars (i.e., not involving a return of the crew to Earth) makes sense because, compared to a round-trip mission, it requires less mass at launch and lower initial costs. This could help mankind reach Mars earlier. A one-way mission does, however, require a different approach to the design of the habitat modules and present additional risks. One of the major risks involves food and nutrition for the space explorers. This means farming their food on another planet that has a very different ecosystem than Earth’s.

Mars’ gravity is 3.711 m/s 2 which is 38% that of Earth, it has sub-zero mean temperature (on average − 63 °C), thin non-breathable CO 2 -rich atmosphere, high Ultraviolent (UV) radiation and savage global dust storms, low pressure atmosphere and lacks readily available liquid water (due to its low pressure to retain water in a liquid form, water instead sublimates to a gaseous state, hence Mars has no oceans and hence no “sea level”). The rotational period and seasonal cycles of Mars are likewise similar to those of Earth [ 16 ]. The lengths of the Martian seasons are about twice those of Earth’s, as Mars’s greater distance from the Sun leads to the Martian year being about two Earth years long [ 17 ]. Has the most clement environment in the solar system after the Earth. It also has the potential to contain habitable environments for life. Since to survive, terrestrial-type life needs an environment with a source of liquid water, organic molecules, and a source of energy.

The first ‘Martians’ will, therefore, be two kinds: plants and humans, who are actually ideal companions. Gardens are the key to settling on Mars as they could help to recycle nutrients, and use the carbon from the toxic Martian atmospheric to produce oxygen through photosynthesis for humans to breathe. Gardens could even, in the long term, provide building materials such as wood and bamboo, and would improve the morale and wellbeing of the crew. The lack of a significant atmosphere, and hence very little greenhouse warming, combined with Mars’ distance from the Sun, make Mars a very cold place indeed. On Mars, near the equator, the duration of daylight is about 12 h, followed by approximately 12 h of darkness [ 18 ]. One of the major hazards involved in planting on Mars will be associated with the exposure to high UV-radiation. High UV-radiation has been shown to be harmful to living organisms, damaging DNA, proteins, lipids and membranes. Therefore, plants exposed to these radiations are at risk and also risky to eat. Physical and atmospheric properties of Mars are shown in Table  2 .

The Moon is an astronomical body that orbits planet Earth, being Earth’s only permanent natural satellite [ 19 ]. It is the second brightest object in the sky after the Sun. It orbits around the Earth once per month. The proximity of the Earth to the Moon makes the Moon an important step beyond Earth orbit [ 1 ]. On average, the distance from Earth to the Moon is about 384,400 km [ 20 ]. Human explorers will conduct scientific research, identify and develop resources, gain experience with establishing human outposts on other planetary bodies, and validate techniques for exploration of more distant destinations [ 1 ]. Such planetary body is the Moon, because it is small and it is readily accessible. The Moon may represent a potential resource for commercial exploitation. There have been many proposals to export lunar resources for use on Earth as well as proposals to use lunar-generated energy and to use the Moon for education, entertainment or space tourism [ 19 ] i.e., focusing on the resource exploitation and commercialization. In addition to the Moon’s intrinsic science value and its potential importance as an observational platform and a resource node, the Moon provides several additional benefits to a stepping-stone approach into the solar system.

In the Moon, there is sharp contrast conditions between day and night, the compositions during the day may be somewhat different from the atmosphere at night. Although the atmosphere of the Moon is very thin, the Moon does have an atmosphere. The composition is not well known, but it is estimated to consist in atoms per cubic centimeter of Helium, Neon, Hydrogen, Argon, Methane, Ammonia, CarbonIVoxide, with trace amounts of Oxygen, Aluminum, Silicon, Phosphorus, Potassium, Sodium, and Magnesium ions.

Even though the Moon has an atmosphere, it is too thin to breathe and includes compounds not good in the lungs [ 21 ]. However, the Moon keeps very little of the atmosphere it receives. Any gas it momentarily captures escapes from the surface very rapidly [ 22 ]. The surface of the Moon is baldly exposed to cosmic rays and solar flares, and some of that radiation is very hard to stop with shielding. Furthermore, when cosmic rays hit the ground, they produce a dangerous spray of secondary particles right at the feet [ 23 ]. Therefore, plants exposed to these radiations are at risk and also risky to eat. The main elements needed for life support—oxygen, hydrogen, nitrogen, and carbon—are available in the lunar regolith, albeit at extraordinarily low concentrations except for oxygen, which is tightly bound chemically within the minerals.

The Moon as a natural space station provides a benign environment with one-sixth gravity for human utilization and exploration. The gravity of the Moon is 1.62 m/s 2 . There is some evidence that the adverse effects of weightlessness on the human body may be absent or substantially reduced in lunar gravity [ 1 ]. Physical and atmospheric properties of the Moon are shown in Table  3 .

Venus is the second planet from the Sun, and considered in many ways to be a twin planet of Earth. It has a similar size, mass, density and gravity, as well as a very similar chemical composition. In other ways, Venus is very different than Earth, with its high surface temperature, crushing pressure, and poisonous atmosphere. One of the strange characteristics of Venus is that it’s actually rotating backwards from the rest of the planets. Seen from above, all of the planets rotate counter-clockwise, but Venus turns clockwise on its axis. Gravity on Venus is 90% the gravity on Earth. The gravity would feel very similar to Earth. Furthermore, the atmospheric pressure on the surface of Venus is 92 times Earth pressure. Venus’ atmosphere is composed almost entirely of carbonIVoxide, and its thick atmosphere acts like a blanket, keeping Venus so hot. Nitrogen exists in small doses in its atmosphere and so do clouds of sulfuric acid. Therefore, the atmosphere absorbs near-infrared radiation, making it easy to observe. The air of Venus is so dense that the small traces of nitrogen are four times that amount found on Earth, although nitrogen makes up more than three-fourths of the terrestrial atmosphere. This composition causes a runaway greenhouse effect that heats the planet even hotter than the surface of Mercury, although Venus lies farther from the Sun, i.e., Venus is not the closest planet to the Sun, it is still the hottest. It has a thick atmosphere full of the greenhouse gas carbonIVoxide and clouds made of sulfuric acid. The gas traps heat and keeps Venus toasty warm. When the rocky core of Venus formed, it captured much of the gas gravitationally. In addition to warming the planet, the heavy clouds shield it, preventing visible observations of the surface and protecting it from bombardment by all the largest meteorites. Venus has no water on its surface, and very little water vapor in its atmosphere. The clouds of Venus appear to be bright white or yellow and are capable of producing lightning much like the clouds on Earth. Most of the surface of Venus is covered by smooth volcanic plains, and its dotted with extinct volcanic peaks and impact craters [ 24 ].

Despite the harsh conditions on the surface, the atmospheric pressure and temperature at about 50 km to 65 km above the surface of the planet is nearly the same as that of the Earth, making its upper atmosphere the most Earth-like area in the Solar System, even more so than the surface of Mars. Due to the similarity in pressure and temperature and the fact that breathable air (21% oxygen, 78% nitrogen) is a lifting gas on Venus in the same way that helium is a lifting gas on Earth, the upper atmosphere has been proposed as a location for both exploration and colonization. This brings about the question, “Should we go to Venus instead of Mars?” Unlike Mars’ thin and useless atmosphere, Venus’ thick atmosphere protects against radiation. Cue a few plans to live in a “cloud city” [ 25 ].

As the Venusian atmosphere supports opaque clouds made of sulfuric acid, this makes optical Earth-based and orbital observation of the surface impossible. Information about the topography has been obtained exclusively by radar imaging. Venus rotation is very slow. It takes about 243 Earth days to spin around just once because it’s so close to the Sun, a year goes by fast. It takes 225 Earth days for Venus to go all the way around the Sun. That means that a day on Venus is a little longer than a year on Venus. Since the day and year lengths are similar, on the Earth, the Sun rises and sets once each day, but on Venus, the Sun rises every 117 Earth days. Since Venus rotates backwards, the Sun rises in the west and sets in the east. Physical and atmospheric properties of Venus are shown in Table  4 .

3 Alternatives for Feeding Astronauts in Long term Missions to Selected Celestial Bodies

Fulfillment of space exploration mission is key, but much more important are the lives of the explorers. Keeping the astronauts alive, jolly and healthy for long term manned mission has recently being a major and important research area. A major contribution seems to be the food they eat. For short term space manned missions and in spaceflight discussed, astronauts food could be taken along with them from Earth, but for manned missions to the Moon, Mars and Venus which are the current research destinations for long term space missions, they must find a means for their nutrition for survival, as most of these proposed missions have being designed to be one-way missions whereby the astronauts will not come back to the Earth.

The life support system for missions includes food and water production. In the space habitat, plants and humans are actually ideal companions. Humans consume oxygen and release carbonIVoxide. Plants return the favour by consuming carbonIVoxide and releasing oxygen. Humans can use edible parts of plants for nourishment, while human waste and inedible plant matter can (after being broken down by microbes in tanks called bioreactors) provide nutrients for plant growth. These plants can even provide medicine. However, how gravity, light, atmosphere, soil, radiation and other conditions affect the plant’s ability to grow needs to be researched and discussed.

3.1 Possible Solutions

How can the space explorers survive indefinitely on other celestial bodies without growing their food? It costs $80,000 to ship four litres of water to the Moon! Let alone the logistics, of shipping water and food to Mars. As on Earth, growing on other celestials require the same basic ingredients for plants to grow. It takes soil (with nutrient), water, oxygen and a good amount of light to get it out of the ground. Since all of these requirements are not constant in each of the selected celestials, a series of solutions are proposed for the basic aspects of a possible development of plants and food to feed the astronauts when the day of colonization arrives.

3.1.1 Soil Simulations

When humans will settle on the Moon or Mars or Venus, they will have to eat there. Food may be shipped, but an alternative could be to cultivate plants in native soils. This will also reduce costs. Having fore knowledge of how plants will grow on Moon, Mars and Venus by simulating their soils is one of these solutions. Reports on the first large scale-controlled experiment to investigate the possibility of growing plants in Mars and Moon soil simulant shows that plants are able to germinate and grow on both Martian and Moon soil simulant for a period of 50 days without any addition of nutrients (see Fig.  5 ). Growth and flowering on Mars regolith simulant (containing a chemical composition almost identical to that of the red planet) [ 26 ] was much better than on Moon regolith simulant and even slightly better than the control; nutrient poor river soil. Plants such as: asparagus, potatoes and marigolds have already been shown to grow in Mars-like soils. Seeds of radish, alfalfa, and mung bean have been observed to sprout in a CO 2 -rich atmosphere like that on Mars. Other examples are: reflexed stonecrop (a wild plant); the crops tomato, wheat, and cress; and the green manure species field mustard performed particularly well. The latter three flowered, and cress and field mustard also produced seeds. Their results show that in principle it is possible to grow crops and other plant species in Martian and Lunar soil simulants.

Comparison between Terrestrial, Lunar and Martian soil

Weiger et al. [ 27 ] reported that in general, germination percentage is highest on Martian soil simulant and lowest on the Moon soil simulant. Leaf forming occurred most on Martian soil simulant and least on Moon soil simulant. This trend is also present for species that form flowers or seeds. Additionally, for the percentage plants still alive after 50 days, Martian soil simulant performed best than moon soil simulant. Martian soil simulant also performed better than Earth soil for most species. The biomass at the end of the experiment was significantly higher for eleven out of the fourteen species on Martian soil simulant as compared to both other soils. The biomass for Earth and Moon soil simulant is often quite similar although for nine species the biomass increment on Earth soil was significantly higher than on moon soil simulant. Apparently, in general, plants were able to develop at the same rate on Martian and Earth soil simulants, but biomass increment was much higher on Mars simulant. This is reflected in both below and above ground biomass, although there are differences at the species level. On average, species in Martian soil simulant performed significantly better than plants in Earth soil with respect to biomass increment. The Mars soil simulant resembles loess-like soils from Europe and holds water better than the other two soils. Moon soil simulant dried out fastest [ 27 ].

Wieger Wamelink from Wageningen University, who is a Dutch environmentalist has been experimenting with these crops on Martian and lunar soil for over 3 years, with the intention of checking whether it was safe to eat them. Now, in his last harvest of tomatoes and potatoes, he determined that the levels of heavy metals in these vegetables are safe to be consumed by humans (see Fig.  6 ). A series of investigations have been carried out that conclude that potatoes, peanuts, strawberries, and tomatoes are the easiest to reproduce in Martian soil.

Potato grown on simulated Martian soil with the corresponding levels of heavy metals

3.1.1.1 Use of CubeSats (Closed System)

Another method adapted with the use of simulation of soil has also being discovered. The International Potato Center (CIP) launched a series of experiments to discover if potatoes can grow under Mars atmospheric conditions and thereby prove they are also able to grow in extreme climates on Earth. This Phase Two effort of CIP’s proof of concept experiment to grow potatoes in simulated Martian conditions began on February 14, 2016 when a tuber was planted in a specially constructed CubeSat contained environment built by engineers from University of Engineering and Technology (UTEC) in Lima based upon designs and advice provided by the National Aeronautics and Space Administration in Ames Research Center (NASA ARC), California. Preliminary results are positive [ 28 ].

The CubeSat houses a container holding soil and the tuber. Inside this hermetically sealed environment the CubeSat delivers nutrient rich water, controls the temperature for Mars day and night conditions and mimics Mars air pressure, oxygen and carbonIVoxide levels. Sensors constantly monitor these conditions and live streaming cameras record the soil in anticipation of the potato sprouting [ 28 ]. CIP scientists concluded that future Mars missions that hope to grow potatoes will have to prepare the soil with a loose structure and nutrients to allow the tubers to obtain enough air and water to allow it to tuberize [ 28 ].

One of the future challenges to produce food in a Mars environment will be the optimization of resources through the potential use of the Martian substratum for growing crops as a part of bioregenerative food systems. In vitro plantlets from 65 potato genotypes were rooted in peat-pellets substratum and transplanted in pots filled with Mars-like soil from La Joya desert in Southern Peru. The Mars-like soil was characterized by extreme salinity (an electric conductivity of 19.3 and 52.6 dS m −1 under 1:1 and saturation extract of the soil solution, respectively) and plants grown in it were under sub-optimum physiological status indicated by average maximum stomatal conductance < 50 mmol H 2 O m −2 s −1 even after irrigation. 40% of the genotypes survived and yielded (0.3–5.2 g tuber plant −1 ) where CIP.397099.4, CIP.396311.1 and CIP.390478.9 were targeted as promising materials with 9.3, 8.9 and 5.8% of fresh tuber yield in relation to the control conditions. A combination of appropriate genotypes and soil management will be crucial to withstand extreme salinity [ 29 ].

The experiment conducted by CIP using the CubeSat and simulated Martian soil can be repeated using the Lunar and Venus regolith.

3.1.2 Solutions to Plant Growth Against the Atmospheric and Radiation Challenges (Environmental)

The most efficient processes for the development of crops on the selected celestials can be done through closed, controlled or soilless cultivation systems as a result of the unfavorable environmental conditions. The atmospheric conditions and the radiation can not support germination, growth and development of plants.

3.1.2.1 Greenhouse Method

Mars has strong potential to eventually support human life because of its close proximity to the Sun and it atmospheric composition. One critical factor to assess is the potential to support and sustain plant growth on Mars. This would be achieved by setting up a greenhouse that can manipulate Mars’ atmosphere to mimic Earth’s. To achieve the goal of growing plants on Mars, a greenhouse will have to be implemented to combat the unfavorable conditions. The main conditions that will need to be altered are the water, atmosphere, temperature, and lighting. Use of greenhouse method is the alteration of the environment to meet the growth requirements of plants. Addition of fertilizer will be required to provide significant nutrient elements that are lacking in the soil. As the soil will still be used to plant. An ideal plant environment is a greenhouse where all vegetal organisms’ needs are supplied within optimal water, light and temperature ranges, according to the space environmental conditions [ 30 ].

The water will need to be harvested and desalinated before it can be used in the greenhouse. The atmosphere within the greenhouse can be manipulated by carbonIVoxide generators and irrigation systems. A Martian greenhouse will need to be well insulated to avoid huge temperature drops at night. Perhaps a combination of passive greenhouse heating during the day, supplemented by electrical heating and lighting at night will be required to provide a suitable growing environment for plants to be grown on Mars. Collecting and storing solar energy is an extremely inefficient process. A major fraction of the energy is lost as heat long before it is made available as light energy for plant growth [ 17 ].

Greenhouse will also be needed for Moon and Venus agriculture. NASA’s growth chamber, ‘Veggie [ 31 ]’, serves as a prototype for the greenhouses that will be required for an ongoing settlement on the Moon or on Mars, and has yielded strong results, with a whole variety of plants having grown successfully, including: onions, cucumbers, bok choy, and lettuce [ 32 , 33 ].

For the greenhouse structure, the types of structures that might be used for plant production on Mars vary from small automatically deployed structures for research purposes to larger structures that would be used to grow plants as part of a manned expedition. The structural requirements will vary depending on the size and purpose of greenhouses, but the functions necessary for successful plant growth will be similar regardless of size [ 34 ] (see Figs.  7 and 8 ).

Single greenhouse layout

Greenhouse by NASA

3.1.2.2 Hydroponics and Aquaponics

Hydroponic is a plant farming method of growing plants inside an enclosed structure using mineral nutrients solution in water without soil, but in a selected growing medium where the lighting, temperature, and nutrients are closely regulated (see Fig.  9 ). In hydroponic technique, water is used to transmit nutrients to plants (see Fig.  10 ). Hydroponics is a subset of hydroculture. Soil to support life in space is not being found, and the logistics of transporting soil are impractical, hydroponics could hold the key to the future of space exploration. Terrestrial plants maybe grown with their roots in the mineral nutrient solution only (liquid hydroponic systems) or in an inert medium, such as perlite, mineral wool, gravel, expanded clay pebbles or coconut husk (aggregate hydroponic systems). The benefits of hydroponics in space are twofold: it offers the potential for a larger variety of food, and it provides a biological aspect, called a bioregenerative life support system. This simply means that as the plants grow, they will absorb carbonIVoxide and stale air and provide renewed oxygen through the plant’s natural growing process. This is important for long range habitation on other planets [ 35 ].

Hydroponic method of plant farming

Water is used to transmit nutrients to plants

3.1.2.3 Aquaponics

The term aquaponics is a portmanteau of the terms aquaculture and hydroponic agriculture. Aquaponics refers to any system that combines conventional aquaculture (raising aquatic animals such as snails, fish, crayfish or prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic environment (see Figs.  11 and 12 ). In normal aquaculture, excretions from the animals being raised can accumulate in the water, increasing toxicity. In an aquaponic system, water from an aquaculture system is fed to a hydroponic system where the by-products are broken down by nitrifying bacteria initially into nitrites and subsequently into nitrates that are utilized by the plants as nutrients. The water is then recirculated back to the aquaculture system. As existing hydroponic and aquaculture farming techniques form the basis for all aquaponic systems, the size, complexity, and types of foods grown in an aquaponic system can vary as much as any system found in either distinct farming discipline [ 36 ]. Thanks to its automatic recirculating system, aquaponics does not require much monitoring or measuring”.

Aquaponics combines aquaculture and hydroponic agriculture aquaponics

The main difficulty in setting up this system in deep space is the time of the establishment of this ecosystem. Indeed, modules containing plants and fish should be sent before the arrival of humans. So, during the trip and waiting for early humans, fish and plants will begin to grow and therefore save time for growth. These modules will be fully autonomous in the first phase of the cycle, finally, astronauts will complete the loop by bringing the last pieces of the ecosystem, composters, their consumption, and waste [ 37 ]. A completely stand-alone system can be created that will provide food self-sufficiency and protection for early settlers through this essential resource. The technology to implement such an ecosystem is now known and used automated on earth so it can be used on Mars [ 37 ].

3.1.2.4 Aeroponics

Aeroponic is the process of growing plants in an air or mist environment where roots are continuously or discontinuously kept saturated with fine drops of nutrients solution without the use of soil or an aggregate medium (see Fig.  13 ). Aeroponics is a soilless cultivation process that uses little water. Scientists have been experimenting with the method since the early 1940s, and aeroponics systems have been in use on a commercial basis since 1983. In 1997, NASA teamed up with AgriHouse and BioServe Space Technologies to design an experiment to test a soilless plant-growth system on board the Mir Space Station. NASA was particularly interested in this technology because of its low water requirement. Using this method to grow plants in space would reduce the amount of water that needs to be carried during a flight, which in turn decreases the payload. Aeroponically grown crops also can be a source of oxygen and drinking water for space crew.

Aeroponic method of growing plants

Aeroponics systems, which utilize a high-pressure pump to spray nutrients and water onto the roots of a plant, are essential for long-term space missions in the future. Aeroponic growing systems provide clean, efficient, and rapid food production. Crops can be planted and harvested year-round without interruptions, and without contamination from soil or pesticide use. Plants grown in aeroponic systems have also been shown to take in more vitamins and minerals, making the plants healthier and potentially more nutritious. These “space gardens” could provide up to half of the required calories for the astronauts through tomatoes, potatoes and other fruits and vegetables. It can also help to recycle nutrients, provide drinking water and create oxygen in space [ 35 ]. According to AgriHouse (product outcome of NASA research program), growers choosing to employ the aeroponics method can reduce water usage by 98%, fertilizer usage by 60%, and pesticide usage by 100%, all while maximizing their crop yields by 45–75%.

3.1.3 Soil Improvement

Another possible solution is to improve the required soil portion needed for agriculture. For example, if the greenhouse method is employed, the soil is still needed.

In case the soil nutrients and other conditions are not perfect for plants growth on the deep space destination, the soil portion could be improved. Poor and less-than-ideal soil for planting could benefit from amendments, which improve the nutrient and moisture levels while supplying aeration and structure. Mixing a 2-inch-thick layer of compost into soil is sufficient when that soil is already relatively good, but heavy clay soil or sandy soil may require a 4–6-inch thick layer of the amendment to reap its benefits. Compost and commercial fertilizer provide nutrients to soil, but applying them regularly is necessary to maintain the soil’s nutrient level. If the soil pH is not correct, then lime could be added to raise the pH or sulfur to lower the pH, but additional 6 months will be required before planting, so the amendment has time to alter the soil’s chemical makeup [ 9 ].

3.1.4 Solution to Water Use of Plants

Mars is revealing more and more evidence that it probably once had liquid water on its surface, and 1 day will become a home away from home for humans. One of the major problems to solve is the water that is needed for the growth of the plants, Mars contains approximately 60% of water, of this, 1% is in the atmosphere and the other is mostly frozen.

The University of Washington has designed an in situ resource utilization system to provide water to the life support system in the laboratory module of the NASA Mars Reference Mission, a piloted mission to Mars [ 38 ]. In this system, the Water Vapor Adsorption Reactor (WAVAR) (see Fig.  14 ), extracts water vapor from the Martian atmosphere by adsorption in a bed of type 3A zeolite molecular sieve. Using ambient winds and fan power to move atmosphere, the WAVAR adsorbs the water vapor until the zeolite 3A bed is nearly saturated and then heats the bed within a sealed chamber by microwave radiation to drive off water for collection. The water vapor flows to a condenser where it freezes and is later liquefied for use in the life support system [ 38 ].

The WAVAR process

On the Moon however, scientists have conjectured that water ice could survive in cold, permanently shadowed craters at the Moon’s poles. For Venus, because of the average temperature of 467 °C, there will not be any water on it, but could water be in the clouds and atmosphere of Venus as it contains 0.002% water vapor?

3.1.5 Biotechnologically Transformation of Food Plants

The environment in Mars, Moon and Venus are inhospitable for plants growth, therefore, plants can be made to survive on these selected celestial bodies by genetic transformation to suite these environments. The genetic transformation is usually done through biotechnological means. This involves isolation of desired gene or the gene of interest from the host’s genome and inserting it into the genome of the organism required to possess the phenotype. Examples include:

Adding features from microscopic organisms called extremophiles that live in the most inhospitable environments on earth. The technique includes gene splicing (genetic or DNA alteration) to remove useful genes from extremophiles and adding them to plants.

Transformation of plants with genes for cold tolerance, e.g., taking useful genes from bacteria that have cold tolerance in arctic ice.

Transformation of other plants with genes from tomato plants that have ultraviolent resistance that grows high in the Andes mountains.

3.1.6 Mathematical/Theoretical Model for Plant Growth Simulation on Selected Celestial Bodies Using Data from Microgravity Facilities and Microgravity Simulations Facilities

Microgravity is an outer space condition of absolute weightlessness. The gravity on the earth is 9.807 m/s 2 . Gravity on the Moon is one-sixth of the gravity on Earth (i.e., dividing 9.807 m/s 2 by 6) and this corresponds to 1.622 m/s 2 . Gravity on the Mars is one-third of the gravity on Earth (i.e., dividing 9.807 m/s 2 by 3) and this corresponds to 3.711 m/s 2 . Gravity on the Venus is nine-tenth of the gravity on Earth (i.e., dividing 9.807 m/s 2 by 9/10) and this corresponds to 8.87 m/s 2 . There is no microgravity in the Moon, Mars and Venus; therefore, microgravity experiments will not be applicable to them since there is no microgravity in them, but theoretical models to get the growth rate of plants in relation to the gravity available on these celestial bodies using available data from microgravity facilities and microgravity simulations facilities. This will give an insight to the expected growth rate and yield of plants to be grown on the selected celestial destinations, if they will be able to deliver the required quantity of nutrients to the crew.

Indeed, gravity has shaped the plant and animal world over millions of years, and man spend much of his live resisting it. Gravity has supplied a constant input throughout the evolution of life on Earth, providing a directional cue by which plants organize cells, tissues, and organs; and they elaborate their body plans. The various means by which the force of acceleration due to gravity is perceived, transduced, and transmitted throughout the body of the plant remains an active and important research enterprise, drawing upon the latest tools in cell biology, biochemistry, molecular genetics, signal transduction, and physiology to advance our understanding of this complex response [ 39 , 40 ]. In addition, the development of an international effort to explore space has provided opportunities to investigate plant growth responses in the microgravity environment of low-Earth orbit aboard Spacelab, Mir, the International Space Station (ISS), US Space Shuttle missions, and various satellite-based lab environments [ 41 , 42 , 43 ].

Plants evolved in the presence of gravity and they developed molecular and cellular mechanisms to adjust growth according to physical forces in a 1 g world. Reduced gravity environments influence the plants physical environment that again affects the physiological transport of water and solutes, and gas exchange between the plant and its surroundings [ 44 ]. Through this force of gravity, the growth of plant organs is coordinated, enabling plants to conquer and explore the space below and above the surface of the Earth. Gravity guides the growth direction of germinating seedlings allowing downwards growing primary roots to explore the soil for water and minerals and upwards growing shoots to synthesize sugars by photosynthesis in the light. This directional growth along the gravity vector, known as gravitropism, allows plants to control and adjust the optimal orientation, but the molecular mechanisms and underlying signaling networks are far from being understood [ 40 , 45 , 46 , 47 , 48 , 49 , 50 ]. It was shown that relocalization of statoliths (starch-filled plastids located in columella cells) and changes in auxin distribution play important roles in gravity signal transduction [ 51 , 52 ].

In the past, many growth chambers for plants (although not regenerative systems) have been designed, produced and then used in Space. Examples of these structures are: AstrocultureTM System (NASA); Plant Growth Unit (NASA), Plant Growth Facility (NASA), Svet (Bulgaria and Russia), Plant Generic BioProcessing Apparatus (NASA), Biomass Production System (NASA), Commercial Plant Biotechnology Facility (NASA), Plant Research Unit (NASA) and the European Modular Cultivation System (ESA). However, access to microgravity, such as provided by the ISS, is rare and costly. Moreover, alternatives to overcome these limitations such as drop towers, suborbital rockets and parabolic flights using airplanes unfortunately allow only short experimental time windows. Ground simulation (bedrest, centrifuge, random positioning machines, magnetic levitation and immersion) are better longer means. Models like the clinostat allow the assessment of microgravity induced deconditioning effects, and reveal gravitational mechanisms in the plant/animal physiological systems, as well as mechanisms involved in adaptation of the plant/animal to microgravity. In particular, they allow researchers to develop and test measures to counter the deleterious effects of weightlessness. Immersion is one of these models, because it creates conditions that closely resemble the gravity-free environment.

2-D clinostat appears as an ideal approach to study aspects of gravity perception and signal transduction as it provides the possibility to simulate microgravity on ground and can be used to prepare or to validate microgravity experiments. 2-D clinostats allow rotating objects along a horizontal axis perpendicular to the gravitational vector to generate high quality of reduced gravity conditions [ 53 , 54 , 55 ]. Several experiments conducted worldwide using clinoration and involving various model plants have improved the understanding of the mechanisms governing plant response to simulated microgravity [ 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. Clinostat principles and different available clinostats are discussed in Brungs et al. [ 66 ]. Clinostat are therefore available in Earth laboratories. Clinostat is an experimental device used in an Earth laboratory to simulate microgravity or to eliminate the effect of gravity.

3.1.6.1 Experimental Example

An example was done by growing wheat on Clinostat at the Space Agency of Nigeria—National Space Research and Development Agency (NASRDA), Abuja, Nigeria. Wheat ( Triticum ) is one of the most important food cereal crops having health benefits [ 67 ]. The properties that make wheat suitable for this experiment is that the seeds are small, easy to handle and fast-growing with germination time of 2 days. Plants roots are structures specialized for anchorage, storage, absorption and conduction [ 68 ]. Plants roots-anatomy is very important for graviresponses and in plant physiology generally. In this particular experiment, the roots of the plants were used for growth rate analysis under 1 g and simulated microgravity. The 1 g result serves as control experiment, while the corresponding growth rate of wheat on the Moon, Mars and Venus were extrapolated from the two values of data gotten.

3.1.6.2 Objectives

To understand what the impact of the gravity of Moon, Mars and Venus will have on the growth rate of wheat plant seeds. The idea behind this is to know what their orientation will be on the Moon, Mars and Venus where there is reduced gravity. With clinostat experiments, the importance and impact of gravity can be demonstrated.

To conduct observational experiments with respect to the differences under microgravity environment and comparing them with those of control experiments under gravity and extrapolating what will be observed on the Moon, Mars and Venus. This was done using the growth rates of wheat determined by their root lengths.

3.1.6.3 Benefits

This scientific research provides insights into Moon, Mars and Venus farming. Understanding how wheat grow on the Moon, Mars and Venus will create a data set of experimental results in various gravity conditions that will contribute to the design of future space experiments and research.

3.1.6.4 Materials and Methods

The seeds of wheat were bought and authenticated to be the actual seeds sought after. The seeds were planted into 2 Petri dishes using plant-substrate called agar, following the standard preparation method in the Teacher’s Guide to Plant Experiments by United Nations Office for Outer Space Affairs (UNOOSA) of the Programme on Space Applications [ 69 ]. The petri-dishes were then put on petri-dish holders in vertical positions (since gravity acts vertically) and then into a wet chamber. The following conditions were maintained throughout the experiment: humidity between 60 to 100%, temperature of 23 °C and light of 50 lx.

After 2 days under 1 g, germination of the seeds with short roots (of at least 50 mm) were observed. The 2 Petri dishes were then taken and labeled “1 g-control” and “Clinorotated”. The 1 g-control labeled sample was remained in the vertical position and the Clinorotated-sample was then placed at the centre of the clinostat using double-sided tape (see Fig.  15 ). This means that the 1 g-control sample was still left under 1 g, while the Clinorotated-sample mounted on the clinostat was then under simulated microgravity. The 1 g-control sample served as a control for growth rate analysis for the clinorotated-sample. The clinorotated-sample mounted on the clinostat was under the following conditions: fast rotation-speed of 85 rpm, rotational-axis angle of 90º and rotation-direction was clockwise.

Uniaxial clinostat and its control box. Rotation position of the clinostat in the picture is horizontal, therefore, having rotational axis angle of 90°

The photos of the 2 petri-dishes were taken every 30 min. The clinorotated-sample was stopped for just some seconds to snap to avoid the effect of gravity. These observations were done for 6 h. Note that the light-conditions, temperature, humidity, rotation-speed, rotation-direction, rotational-axis angle (vertical or horizontal), and time of observation are the experimental variables for Clinostat experiments.

At the end of observations, the root-anatomy of wheat plants seeds were studied using specialized-software called ImageJ to analyse the roots lengths from the two sets of pictures taken. The grand average root lengths of all the seeds were calculated per hour to give the growth-rates.

3.1.6.5 Results

The data obtained were the two sets of photos of the roots which show the “1 g-control” and “Clinorotated” roots (see Figs.  16 and 17 ). An image-processing application soft-ware called ImageJ was used to analyse these photos.

Photo of the 1 g-control sample of wheat

Photo of the clinorotated sample of wheat

3.1.6.6 Growth Rate of the Roots

The pictures of the 1 g-control and the clinorotated roots of the wheat were used for this analysis. This was done by measuring the length of the roots, which thereby allowed their growth rate to be determined. It had three roots growing per seed, the longest root was measured. The length of the roots was measured by drawing a line which is exactly 10 mm long on each petri-dish. This line was used to standardize 10 mm length on the ImageJ software serving as a fixed length in the photo. After standardization, the length measurement tool was used to measure the length of each of the roots in mm. The clinorotated sample of wheat plant showed increased growth rate per hour than the counterpart 1 g-control sample (as shown in Table  5 ). Average value of all the length of the nine 1 g-roots for each time points was calculated and then, the grand-average of the lengths were then calculated (as shown in Table  6 ). This grand-average value was then divided by 6 which is the duration time (in hours) of the time of observation.

Since the plant was examined for 6 h, therefore, the growth rate of the1 g-control sample is 26.676/6 = 4.446 mm/h.

Since the plant was examined for 6 h, therefore, the growth rate of the Clinorotated sample is 29.352/6 = 4.892 mm/h.

3.1.6.7 Mathematical/Theoretical Model for Simulating Plant Growth on the Moon, Mars and Venus

The grand average of the growth rate of the 1 g control Sample is 26.676 mm

The grand average of the growth rate of the Clinorotated Sample is 29.352 mm

The Moon’s gravity is 1/6 of the Earth’s gravity, therefore the root length of wheat that will be planted on Moon will be 26.676/6 = 4.446 mm (as shown in Table  7 ).

For the simulated microgravity, the Moon’s wheat root length will be 29.352/6 = 4.892 mm (as shown in Table  7 ).

(as shown in Table  8 ).

Since the plant was examined for 6 h, therefore, the growth rate will be 4.669/6 = 0.778 mm/h.

The Mars’ gravity is 1/3 of the Earth’s gravity, therefore, the root length of wheat that will be planted on Moon will be 26.676/3 = 8.892 mm (as shown in Table  7 ).

For the simulated microgravity, the Mars’ wheat root length will be 29.352/3 = 9.784 mm (as shown in Table  7 ).

Since the plant was examined for 6 h, therefore, the growth rate will be 9.338/6 = 1.556 mm/h.

The Venus’ gravity is 9/10 of the Earth’s gravity; therefore, the root length of wheat that will be planted on Moon will be 26.676 × 9/10 = 24.0084 mm (as shown in Table  7 ).

For the simulated microgravity, the Venus’ wheat root length will be 29.352 × 9/10 = 26.4168 mm (as shown in Table  7 ).

Since the plant was examined for 6 h, therefore, the growth rate will be 25.213/6 = 4.202 mm/h.

Observations were made using the photos of growth of wheat under 1 g and on simulated microgravity using clinostat. The photos of the 1 g-control showed that the roots continuously grew vertically as stimulated by the Earth’s gravity. For the clinorotated roots, however, nothing stimulates their growth in any direction. The theoretical/mathematical model has made it very easy to simulate the rate of growth of wheat on the Moon, Mars and Venus and therefore, the length of time that the plants will use to grow till full usage can also be estimated.

These all add to the analytical knowledge of the effect of various gravity conditions on wheat for future space missions. The extrapolated result, therefore, will give a great idea and result into Moon, Mars and Venus farming for crews’ survival (see Fig.  18 ).

Graph of wheat seeds growth on the earth and in simulated microgravity with the extrapolated growth values in Moon, Mars, and Venus using the root lengths and time after germination

4 Food Choice Considering Psychosocial and Cultural Factors

Psychological and social issues will affect space explorers crew due to the isolation, confinement, and long separation from family and friends. Cultural issues, interpersonal stressors, effects of long-term microgravity and radiation, extreme isolation and loneliness, limited social contacts and novelty, lack of support from Earth due to communication delays, family problems at home, gender roles, increased home sicknesses, depression, habitat design, sleep, sexual attraction/tension, etc., are some of the psychosocial issues [ 70 ], and food will not be an exception. Over the course of a few decades, psychological research into “analogue sites” here on earth, simulations, and astronauts living and working in orbit has started to show how humans are affected by such environments. In general, findings show the potential for conflict or emotional deterioration during long-term isolated periods, but it may have more to do with people’s perceptions of their environment more so than the environment itself. Even still, living in isolated and confined areas can cause stress and problematic behaviours that may interfere with productivity and relationships [ 71 ]. Food will also be an important factor. As a result of the crew members from different parts of the world with different cultural backgrounds and food, not eating the desired food may affect the morale of some crew members. Food choice for astronauts affects them psychosocially. They should be allowed to select their menu as long as it constitutes the required nutrients. With the advent of high-tech 3D food printers, freshly prepared food to the crew-member’s preferences will be made possible.

5 Discussion

Early explorers discovered the importance of nutrition, often at their peril. There is therefore, a need to carefully prepare ahead on the feeding of crew on the surfaces of Moon, Mars and Venus by growing their crops themselves. Several suggestions and recommendations in this project have being given to make this possible. This include the seeds growth rate extrapolations for Moon, Mars and Venus from microgravity/simulated microgravity platforms. Upon research, viable and desired seeds should be taken along with the crew. If plants can be successfully grown on Moon, Mars and Venus, there is a higher chance of sustaining human life and growth in the future, as well as having the astronauts well nourished.

Advancements in food nutrient to meet the challenges of space have resulted in many commercial products. Very soon much more from space food spin-offs will be seen on the shelves of departmental stores. Therefore, food technology spin-offs from space are beneficial throughout the world. Advancements in food packaging, preservation, preparation and nutrient to meet the challenges of space resulted in many commercial products. Research conducted to determine the impact of spaceflight on human physiology and subsequent nutritional requirements will also have direct and indirect applications in Earth-based nutrition research. Today hydroponics and aeroponics are used in agriculture around the globe [ 72 ].

6 Conclusions

Various alternatives to feeding crew members on deep space missions to selected celestial destinations of Moon, Mars and Venus were analyzed. It will be too costly to be sending food to mission crews at these destinations; therefore, alternatives of planting by crew to feed themselves are given in this project. The characteristics of the Earth that makes it habitable for plants to grow were used to judge if the Moon, Mars and Venus are habitable for plants to grow. This was because growing on other celestials require the same basic ingredients for plants to grow on Earth.

Various hazards to plant as a result of the hostile environment of these celestials were identified, creating a comprehensive list of risks requiring mitigation. These hazards were then evaluated and possible solutions for risk mitigation on plants were proposed based on literature review and experimental research. The results are a list of recommendations that should be considered for feeding the crew on deep manned space missions on the Lunar, Martian and Venus surfaces.

The study found the following researches on Earth as the possible solutions to be able to design how to feed the crew members on the missions at their various selected celestial destinations. Growing seeds on soil simulations (of Moon, Mars and Venus) on the ground and using CubeSats; solutions to plant growth against the atmospheric and radiation challenges (environmental) using greenhouse, aquaponics, hydroponics, aeroponics and soil improvement methods; solution to water use of plants; biotechnologically transformation of food plants to survive on the selected celestial destinations; and extrapolating growth rates of seeds from microgravity/microgravity simulation platforms to develop mathematical/theoretical models for plant growth on the various celestial destinations and to know if the seeds will give the crew members the desired quantity of nutrients; an experimental research example was given for the microgravity/microgravity simulation platforms.

The study found that growing plants on the surface of the Mars, Moon and Venus without any other aid such as greenhouse, soil improvement, etc., is not scientifically possible as a result of their hostile environment. Therefore, the various alternatives already analyzed should be looked into more to serve as possible solutions for feeding the crews. Another key finding of the study is that when astronauts are able to grow and eat the kind of food they want in long term space missions, this reduces the effect of psychosocial of isolation, confinement, and long separation from family and friends on them. The proposed high-tech 3D food printers will also serve as part of the solution to challenges caused by food related psychosocial. Apart from the psychosocial roles of food, the physiological roles of the nutrients in the food cannot also be over-emphasized on crew’s health.

In all, some of the possible solutions to growing seeds on the selected celestial destinations are already successfully developed. It is then within our reach to start or to complete the on-going design/research of the other mentioned possible solutions to further clear the path for crewed missions to deep space missions.

Change history

07 march 2019.

The article titled Space Food and Nutrition in a Long Term Manned Mission in Special Issue of AAST has copyright issues on figure��1-figure��14. The main author did not get permission from the coauthor within the deadline. So the main author removed figure��1-figure��14 and corresponding texts. Former Figures��15 to 18 were renamed Figures��1 to 4.

Abbreviations

National Aeronautics and Space Administration

International Potato Center

National Space Research and Development Agency

United Nations Office for Outer Space Affairs

Ultraviolent

Huntress W, Stetson D, Farquhar R, Zimmerman J, O’Neil W, Bourke R, Foing B (2006) The next steps in exploring deep space, a cosmic study by the International Academy of Astronautics, 20 Feb 2006, http://www.lpi.usra.edu/lunar/strategies/AdvisoryGroupReports/iaa_report.pdf . Accessed 21 June 2017)

United-Nations (2017) The World Population Prospects: the 2017 Revision, published by the UN Department of Economic and Social Affairs

Lupisella ML (2001) Human mars mission contamination issues, science and the human exploration of mars, 11–12 Jan 2001, NASA Goddard Space Flight Center, Greenbelt, MD. LPI Contribution No. 1089. Accessed 15 Nov 12)

Taylor Redd N (2018) Red giant stars: facts, definition and the future of the sun: space.com contributor

Musk E. If we make it to Mars, we will have answered the question of whether humanity is fated to be a single-planet or multi-planet species. Tesla Founder

Oko D (2015) On the long trip to Mars, what will astronauts eat? https://www.houstonchronicle.com/local/gray-matters/article/On-the-way-to-Mars-what-will-astronauts-eat-6248511.php . Accessed 15 June 2018)

NASA (National Aeronautics and Space Administration) (1999) Space food and nutrition, an educator’s guide with activities in science and mathematics

Atmosphere of Earth, https://en.wikipedia.org/wiki/Atmosphere_of_Earth . Accessed 21 June 2017)

Harrington J, What are the three important benefits that soil provides? http://homeguides.sfgate.com/three-important-benefits-soil-provides-100960.html

Michael CH (2006) The surface of Mars, Cambridge planetary science series 6 (Cambridge University Press), ISBN 0-521-87201-4, p 16

Quizlet, Chapter 12 learning review, what is the difference between soil and regolith, https://quizlet.com/39839469/chapter-12-learning-review-flash-cards/

MacElroy RD, Kliss M, Straight C (1992) Life support systems for Mars transit, Adv. Space Res 12:159–166. Mohr H, Blue light responses: phenomena and occurrence in plants and microorganisms. Senger H (ed) CRC Press

Kag B (2012) Res Rev J Agric Sci Technol 1(1):26–35

Google Scholar  

Herbert GW (1996) One way to mars—the case for Mars VI Workshop

Mackenzie B (1998) One way to Mars—a permanent settlement on the first mission. Presented at the International Space Development Conference

Heldmann LJ, Jennifer L et al (2005) Formation of Martian gullies by the action of liquid water flowing under current Martian environmental conditions. J Geophys Res 110(E5):7

Article   Google Scholar  

Kluger J (1992) Mars, in earth’s image. Discover Magazine, Retrieved 03 Nov 2009

Sunlight on Mars—Is there enough light on Mars to grow tomatoes? https://www.firsttheseedfoundation.org/resource/tomatosphere/background/sunlight-mars-enough-light-mars-grow-tomatoes/

https://www.google.com.ng/?gfe_rd=cr&ei=wTdJWff8F8jO8gedzIuABQ#q=what+is+the+distance+of+the+Moon+from+the+earth&spf=1498082193155 . Accessed 21 June 2017)

https://www.space.com/18145-how-far-is-the-Moon.html . Accessed 21 June 2017)

What is the Moon made off, https://www.thoughtco.com/what-is-the-Moon-made-of-604005 . Accessed 21 June 2017)

Air Pollution on the Moon, http://www.geoffreylandis.com/Moonair.html .Accessed 06 Dec 2016)

NASA, Radioactive Moon. Science Beta, 2005

Redd NT (2012) Venus’ atmosphere: composition, climate and weather

Carter J (2018) Should we go to Venus instead of Mars? https://www.techradar.com/news/should-we-go-to-venus-instead-of-mars

Marín E (2016) Las plantas cultivadas en suelo marciano son perfectamente comestibles. https://es.gizmodo.com/las-plantas-cultivadas-en-suelo-marciano-son-perfectame-1782574207 . Accessed 05 May 2018)

Wamelink GWW, Frissel JY, Krijnen WHJ, Verwoert MR, Goedhart PW (2014) Can plants grow on mars and the moon: a growth experiment on mars and moon soil simulants. PLoS One 9(8):e103138. https://doi.org/10.1371/journal.pone.0103138

Article   ADS   Google Scholar  

International Potato Center (CIP) (2017) Indicators show potatoes can grow on mars. https://cipotato.org/blog/indicators-show-potatoes-can-grow-mars/ . Accessed 30 Apr 2018

DA Ramírez (2017) International Journal of Astrobiology, Cambridge University, Press Extreme salinity as a challenge to grow potatoes under Mars-like soil conditions: targeting promising genotypes 1 (2017), Page 1 of 7 https://doi.org/10.1017/S1473550417000453. https://www.cambridge.org/core/services/aop-cambridgecore/content/view/5B9C255DC0CC2FA7F0C0849C5FECD0BC/S1473550417000453a.pdf/extreme_salinity_as_a_challenge_to_grow_potatoes_under_marslike_soil_conditions_targeting_promising_genotypes.pdf . Accessed 02 May 2018)

De Micco V, Aronne G, Colla G, Fortezza R, De Pascale S (2009) Agro-biology for bioregenerative life support systems in longterm space missions: general constraints and the Italian efforts. J Plant Interactions 4(4):241–252. https://doi.org/10.1080/17429140903161348

Herridge L, Griffin A (2017) How does your space garden grow? https://www.nasa.gov/feature/how-does-your-space-garden-grow . Accessed 23 June 2018)

NASA (National Aeronautics and Space Administration), A Plant Growth Chamber. https://www.nasa.gov/audience/foreducators/pgig003.html . Accessed 24 June 2018)

Griffin A (2017) Cabbage patch: Fifth crop harvested aboard space station. http://www.nasa.gov/feature/cabbage-patch-fifth-crop-harvested-aboard-space-station . Accessed 23 June 2018

Schlehahn D, Boudreau A, Barber B, Kowalchuk B, Langman B, Worobec J (2017) Can a greenhouse be established on Mars? Univ Saskatchewan Undergrad Res J 4(1):1–13

Alavudeen A (2014) A seminar Report on Space Food TechnoKerala Agricultural University, Post Harvest Technology and Agricultural Processing, Kelappaji College of Agricultural Engineering and Technology, Tuvanur-679573. Malappuram, Kerala

Rakocy JE, Bailey SD, Shultz CR, Thoman SE (2013) Update on Tilapia and Vegetable Production in the UVI Aquaponic System (PDF). University of the Virgin Islands Agricultural Experiment Station, Archived (PDF) from the original on 2 March 2013, Retrieved 11 March 2013

Plevin P, Foullon P (2016) Autonomous aquaponic system to recreate an ecosystem for Mars settlers, IAC-16, A5, IP,3, x34188, 67th International Astronautical Congress, Guadalajara, Mexico

Grover MR (1998) Extraction of atmospheric water on mars in support of the mars, reference mission department of aeronautics and astronautics. University of Washington, Box 352400 Seattle, WA 98195-2400 Mars Society Founding Convention, Boulder, CO. file:///C:/Users/Andrea/Downloads/WAVAR_Paper_Mars_Soc_conf_1998.pdf. Accessed 05 May 2018)

Kiss JZ (2000) Mechanisms of the early phases of plant gravitropism. Crit Rev Plant Sci 19:551–573

Bancaflor EB, Masson PH (2003) Plant gravitropism, unraveling the ups and downs of a complex process. Plant Physiol 133:1677–1690

Ferl RR, Wheeler HG, Levine AP (2002) Plants in space. Curr Opin Plant Biol 5:258–263

Perbal G, Driss-Ecole D (2003) Mechanotransduction in gravisensing cells. Trends Plant Sci 8:498–504

Brinckmann E (2005) ESA hardware for plant research on the International Space Station. Adv Space Res 36:1162–1166

Porterfield DM (2002) The biophysical limitations in physiological transport and exchange in plants grown in microgravity. J Plant Growth Regul 21:177–190

Palme K (2005) Microgravity applications programme. In: Elman-Larsen B (ed) Successful teaming of science and industry, pp 396–403

Teale WD, Paponov IA, Palme K (2006) Auxin in action: signaling, transport and the control of plant growth. Nat Rev Mol Cell Biol 7:847–859

Hashiguchi Y, Tasaka M, Morita MT (2013) Mechanism of higher plant gravity sensing. Am J Bot 100:91–100

Cui D, Zhao J, Jing Y, Fan M, Liu J, Wang Z, Xin W, Hu Y (2013) The Arabidopsis IDD14, IDD15, and IDD16 cooperatively regulate lateral organ morphogenesis and gravitropism by promoting auxin biosynthesis and transport. PLoS Genet 9:e1003759

Sang D, Chen D, Liu G, Liang Y, Huang L, Meng X, Chu J, Sun X, Dong G, Yuan Y, Qian Q, Li J, Wang Y (2014) Strigolactones regulate rice tiller angle by attenuating shoot gravitropism through inhibiting auxin biosynthesis. Proc Natl Acad Sci USA 111:11199–112204

Sack FD, Suyemoto MM, Leopold AC (1985) Amyloplast sedimentation kinetics in gravistimulated maize roots. Planta 165:295–300

Singh M, Gupta A, Laxmi A (2014) Glucose and phytohormone interplay in controlling root directional growth in Arabidopsis . Plant Signal Behav 9:e29219

Leitz G, Kang BH, Schoenwaelder MEA, Staehelin LA (2009) Statolith sedimentation kinetics and force transduction to the cortical endoplasmic reticulum in gravity-sensing Arabidopsis columella cells. Plant Cell 21:843–860

Hemmersbach R, Von der Wiesche M, Seibt D (2006) Ground-based experimental platforms in gravitational biology and human physiology. Signal Transduct 6:381–387

Thiel CS, Paulsen K, Bradacs G, Lust K, Tauber S, Dumrese C, Hilliger A, Schoppmann K, Biskup J, Golz N, Sang C, Ziegler U, Grote KH, Zipp F, Zhuang F, Engelmann F, Hemmersbach R, Cogoli A, Ullrich O (2012) Rapid alterations of cell cycle control proteins in human T lymphocytes in microgravity. Cell Commun Signal 10:1

Herranz R, Anken R, Boonstra J, Braun M, Christianen PCM, de Geest M, Hauslage J, Hilbig R, Hill JA, Lebert M, Medina J, Vagt N, Ullrich O, vanLoon JWA, Hemmersbach R (2013) Ground-based facilities for simulation of microgravity, including terminology and organism-specific recommendations for their use. Astrobiology 13:1–17

Gallegos GL, Hilaire EM, Peterson BV, Brown CS, Guikema JA (1995) Effects of microgravity and clinorotation on stress ethylene production in two starchless mutants of Arabidopsis thaliana . J Gravit Physiol 2:153–154

Kordyum EL, Danevich LA (1995) Calcium balance changes in tip growing plant cells under clinorotation. J Gravit Physiol 2:147–148

Kordyum E, Adamchuk N (1997) Clinorotation affects the state of photosynthetic membranes in Arabidopsis thaliana (L.) Heynh. J Gravit Physiol 4:77–78

Aarrouf J, Darbelley N, Demandre C, Razafindramboa N, Perbal G (1999) Effect of horizontal clinorotation on the root system development and on lipid breakdown in rapeseed (Brassica napus) seedlings. Plant Cell Physiol 40:396–405

Adamchuk NI, Fomishina RN, Mikhaylenko NF, Zolotareva EK (1999) Photosynthetic apparatus of pea leaves under clinorotation conditions. J Gravit Physiol 6:143–144

Syvash OO, Adamchuk NI, Dovbysh EP, Zolotareva EK (2008) Effect of clinorotation on Auxin as a model for the integration of hormonal signal processing and transduction. Mol Plant 1:229–237

Shevchenko GV, Kordyum EL (2005) Organization of cytoskeleton during differentiation of gravisensitive root sites under clinorotation. Adv Space Res 35:289–295

Sobol MA, Gonz´alez-Camacho F, Kordyum EL, Medina FJ (2007) Changes in the two-dimensional proteome of the soluble fraction of nuclear proteins from Lepidium sativum root meristematic cells grown under clinorotation. J Gravit Physiol 14:109–110

Soh H, Auh C, Soh WY, Han K, Kim D, Lee S, Rhee Y (2011) Gene expression changes in Arabidopsis is seedlings during short-to long term exposure to 3-D clinorotation. Planta 234:255–270

Brykov V, Kordyum E (2015) Clinorotation impacts root apex respiration and the ultrostructure of mitochondria. Cell Biol Int 39:475–483

Brungs S, Egli M, Wuest SL, Christianen PCM, Van Loon J, Ngo AJ, Hemmersbach R (2015) Ground-based facilities to simulate microgravity. Microgravity Sci, Technol

Health benefits of wheat. https://www.organicfacts.net/health-benefits/cereal/wheat.html (accessed 07.09.16)

Root System Anatomy and Morphology, https://masters.agron.iastate.edu/classes/533/lesson03/3.2.html . Accessed 14 Jan 2017

United Nations (2013) Teacher’s guide to plant experiments in microgravity, human space technology initiative. United Nations Programme on Space Applications, New York

Kanas N, The New Martians, a scientific novel (2014) ISBN: 978-3-319-00974-2. http://www.springer.com/978-3-319-00974-2

Slobodian R (2012) Psychosocial challenges of living in space: isolation and culture. York University, Toronto

Hoehn A (1998) Root wetting experiments aboard NASA’s KC-135 microgravity simulator. BioServe Space Technologies, Boulder

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Oluwafemi, F.A., De La Torre, A., Afolayan, E.M. et al. Space Food and Nutrition in a Long Term Manned Mission. Adv. Astronaut. Sci. Technol. 1 , 1–21 (2018). https://doi.org/10.1007/s42423-018-0016-2

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Original research article, to the farm, mars, and beyond: technologies for growing food in space, the future of long-duration space missions, and earth implications in english news media coverage.

• 1 School of Communication, Simon Fraser University, Burnaby, BC, Canada
• 2 School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada

The climate crisis, natural resource exploitation, and concerns around how to feed a growing world population have resulted in a growing chorus identifying the need for a Plan B. For some, this Plan B entails preparing for long-duration space missions and the development of human settlement on Mars. To plan for long-duration space missions, the development of food production technologies that can withstand extreme conditions such as poor soil, lack of gravity, and radiation are increasingly prioritized. These technologies may include genetic engineering, digital agriculture, 3D bioprinting, synthetically grown meat and more. Government and corporate proponents of long-duration space missions—NASA and SpaceX, among others—are actively funding agricultural research in space. They argue that the technologies developed for space will have positive implications beyond Mars—directly benefitting Earth and its inhabitants. This paper demonstrates that news reporting on the technology has been overall uncritical. Media narratives surrounding issues of food growth in space have not been studied. This study analyzes how English news media coverage ( n = 170) from 67 publications report the feasibility of long-duration space missions, human settlements, and high-tech agricultural technologies. We provide a cross-section of the types of agricultural technologies being covered, the key organizations and actors in the field, and a critical analysis of media narratives. Using mixed methods content and discourse analysis, this study finds that the news media publications overwhelmingly portray long-duration space missions as both inevitable and a positive good for humanity. Without critically assessing the societal implications of food technologies for long-duration space missions vis-à-vis their benefits on Earth, we risk glossing over systemic and structural inequalities in the food system.

Introduction

With a projected 9–12 billion people to inhabit the Earth by 2100 ( United Nations, 2022 , p. 27) and concerns about the impact of climate change on global food production, a growing number of scholars have identified the importance of exploring technological innovations that can grow food faster, more sustainably, and with fewer resources ( Wolfert et al., 2017 ). To increase food production, agri-tech solutions such as digital agricultural technologies ( Rotz et al., 2019 ), genetic engineering ( Montenegro de Wit, 2022 ), lab meats ( Moritz et al., 2022 ), 3D bioprinting ( Krujatz et al., 2022 ) and more have been proposed. There is no clear scientific consensus on the benefits of these technological solutions for Earth, and some innovations (e.g., lab meat) are not without controversies ( Katz-Rosene and Martin, 2020 ). Interestingly, the use of these technologies is being extensively explored beyond Earth for space and long-duration space missions. In addition to benefitting astronauts and future spacefarers, these technologies are often claimed to serve the purpose of increasing food systems resiliency on Earth.

At the risk of stating the obvious, astronauts need to eat in space. For decades, astronaut meals consisted of freeze-dried foods and paste in tubes—unappetizing food at best tolerated by astronauts ( Obrist et al., 2019 ). For relatively short space missions, the quality of food has historically not been a priority. As space missions become longer—National Aeronautics and Space Administration (NASA) Astronaut Mark Vande Hai completed 355 days on a single mission on the International Space Station (ISS), and Astronaut Scott Kelly completed 340 days ( Garcia, 2016 )—the quality and nutrition of food need to improve, as the astronauts' health and wellbeing (both physical and mental) are highly dependent on diet. The growing length of the space missions noted above is only a fraction of that of theorized crewed Mars missions, which could last upwards of 2 years ( Williams, 2015 ).

Media outlets have reported on Elon Musk's personal and commercial ambition exerted through his company SpaceX—which as of March 2, 2020, became the first private company to transport astronauts to the ISS—to colonize Mars and establish a settlement of one million colonists by 2050 ( McFall-Johnsen and Mosher, 2020 ). As noted on the SpaceX website, the focus on “Mars and Beyond” is a pathway “to making humanity multiplanetary” and “about believing in the future and thinking that the future will be better than the past”. For Jeff Bezos' company Blue Origin, space tourism, the development of new employment and living opportunities in space, as well as the movement of “damaging industries into space to preserve earth” are among its core values ( About Blue, n.d. ). These are put simply by its official motto: “For the Benefit of Earth”.

If Mars and other long-duration deep space missions compose the new frontier in exploration, then the agricultural technologies required for such endeavors are the new frontier in food studies. Research in this realm is novel. With the exception of a new book “ Dinner on Mars: The technologies that will feed the red planet and transform agriculture on earth ” ( Newman and Fraser, 2022 ) which argues that in figuring out how to sustain colonies on Mars, humanity will be able to also sustain themselves on Earth, scholarly studies in this realm have been limited to technical and logistical food growth experimentation in space ( Meinen et al., 2018) , nutrition concerns for astronauts ( Bychkov et al., 2021 ), or varieties of space menu proposals ( Bourland and Vogt, 2010 ). NASA's Kennedy Space Center has been actively researching space agriculture using public funding ( NASA, 2021 ). Private companies are taking increasingly active roles in space exploration and food research.

Criticism around the privatization of space exploration and use of public funds for space food research centers around calls to reprioritize spending toward solving Earth-based issues instead ( Gohd, 2021 ). Long-duration space missions rely on the promises of novel and undeveloped food agricultural technologies (agri-tech), which will require extensive amounts of funding. Organizations developing these technologies—both public and private—often claim that the same novel technologies can revolutionize and transform agriculture on Earth for the better ( Newman and Fraser, 2022 ). This study seeks to develop a critical understanding of this new frontier of research by analyzing relevant discourse in the news media. It fills a gap in a niche and cutting-edge field of food study that will grow should long-duration space missions be realized. The study seeks to answer the following research questions:

(1) How do English news media articles present the issue of food production in the context of long-duration space missions (e.g., Mars Missions)?

(2) What types of agricultural technologies and who are the stakeholders identified for food production for the purposes of long-duration space missions in English media articles?

To sift through and convert the articles' contents into meaningful data points, we employed a mixed methods content analysis approach, combining computerized processes with qualitative critical analysis. Methodological practices of news media analysis vary wildly between fields and subjects, but almost all are conducted using a form of content analysis ( Krippendorff, 2004 ). Similar studies into niche news topics typically employ highly customized content analysis or framing processes (see Rickard and Feldpausch-Parker, 2016 ; MacLeod, 2019 ; Pasquinelli and Trunfio, 2020 ). The mixed-methods content analysis approach enabled both quantitative data analysis of the corpus ( n = 170) and qualitative deep-reading analysis of a random sample of the articles ( n = 40) to highlight the narratives about agricultural technologies for growing food in space.

Literature review

Earth and space connection: extreme environments.

While astronauts aboard the ISS can rely on resupply shipments of food from Earth, long-duration space missions will likely have no such support due to the massive distances that will be traversed. Growing food in space, whether in zero gravity or on other planets, will entail learning to farm in extreme environments. This challenge became the raison d'etre of a 2021 international competition called the “Deep Space Food Challenge”, which was launched by NASA and the Canadian Space Agency (CSA) and administered by the Methuselah Foundation ( Deep Space Food Challenge, n.d. ). This international collaboration between space agencies is a public competition that seeks to support the development of novel food production technologies that require minimal inputs, maximize safe, nutritious, and palatable food outputs for long-duration space missions, and have the potential to benefit humanity on Earth. Beyond growing food for long-duration missions and the benefits for astronauts, The Challenge specifically identifies a goal to “improve the accessibility of food on Earth, in particular, via production directly in urban centers and in remote and harsh environments” ( Deep Space Food Challenge, n.d. ). The period around the Challenge became a focus during the early stages of this research project because, at least initially, it appeared to command news media attention.

The recurrent notion that developments in space food technology will directly benefit food growth on Earth is founded on a techno-optimistic understanding of space technology development but nonetheless makes practical sense. Some claims are based on the idea that experience growing food in extreme environments in space can help improve food security and increase food production in extreme environments on Earth (e.g., in the desert or remote arctic). For example, in some of the coastal regions of the Middle East and North Africa (MENA), deemed as “extreme environments”, scholars are reframing the narrative of the challenging landscape as an “incredible untapped development potential” waiting for the right technologies ( Lefers et al., 2020 ). As the authors of this study argue, through controlled environment agriculture, greenhouses, infrared collecting solar panels, and low-energy saltwater cooling, these marginal lands have the potential for productive agriculture ( Lefers et al., 2020 ). Beyond deserts in the MENA region, other studies covering “extreme environments” have focused on the Arctic and Northern environments, particularly on technological innovations that are being used to increase food security and reduce Northern reliance on imported foods from southern regions ( Chen and Natcher, 2019 ). Climate opportunism has also resulted in a turn toward the Arctic as an agricultural frontier. Bradley and Stein (2022 , p. 207) have documented the growing interest in “farming the tundra” and the idea of the Arctic as the “Last Frontier” as current zones of crop production are impacted by climate change. In a study examining the potential for the Arctic to become a self-sustaining food-producing region, Chen and Natcher (2019) found that despite numerous claims and excitement about moving technologies such as greenhouses into the Arctic, there is a lack of research identifying tangible benefits to food security. While scholars noted that greenhouses in the Arctic have been successful in serving as spaces for youth training and education ( Allen, 2014 ; Lamalice et al., 2018 ) there is still little information that demonstrates improved food security in the Arctic through these types of technologies ( Chen and Natcher, 2019 ). Issues such as availability (because of limited foods from the greenhouse), access to the space, and challenges with procuring materials, soil, and the expensive cost of energy to maintain these spaces mean that these innovations are not simple fixes to the complex food insecurity issues caused by poverty, lack of access to arable land, and the lack of Indigenous food sovereignty stemming from colonization ( Spring et al., 2018 ).

Expanding responsible agri-food innovation to outerspace

The history of global agricultural technological innovation started in the 1940s with the green revolution ( Patel, 2012 ), a top-down agricultural development project funded by the Rockefeller Foundation and supported by the United States (US) government to be implemented in the global South (started in Mexico). The green revolution promised to solve hunger through the development of “miracle wheat”, and a package of chemical fertilizers, pesticides, herbicides, and hybrid seeds by transforming local farming practices, often through state coercion ( Patel, 2012 ). The 1947–73 food regime, as identified in food regime theory shaped the ability for the US to finance international agricultural ventures through the World Bank ( Patel, 2012 ). While increased yields were observed in some cases, the increase in yields did not necessarily trickle down to the people, and the technologies and suite of agro-chemical products resulted in massive farm debt and ecological degradation ( Shiva, 1991 ). The techno-optimist approach to growing food has continued with the concept of “Smart Farming” and the framework of a fourth agricultural revolution in the digitization of agriculture ( Rose and Chilvers, 2018 ). The digitization of agriculture through smart farming relies on data and software-intensive platforms ( Clercq et al., 2018 ) supported by the Internet of Things (IoT). Smart farming and smart technologies integrate tools such as artificial intelligence (AI), robotics, drones, advanced monitoring systems, and more ( Rose and Chilvers, 2018 ). It is argued that these technologies will produce more food, produce it faster, and make farmers more money amidst increasingly challenging agricultural environments ( Rotz et al., 2019 ). While there may be benefits to these technologies through high-tech jobs or more efficient use of inputs such as fertilizers and pesticides ( Rose and Bruce, 2018 ), scholars have also raised caution around the digitization of agriculture and how smart technologies have resulted in the growing farming assetization that have contributed to fostering more inequality concerning land access and farmer autonomy ( Duncan et al., 2022 ), the issue of data security/third-party uses of agricultural data ( Klerkx et al., 2019 ), challenges around access to repair ( Carolan, 2018 ), as well as the lack of consideration around issues such as equity and food sovereignty in digital agriculture education ( Soma and Nuckchady, 2021 ). In addition to the digitization of agriculture, technological innovations in agriculture also include synthetic/lab-grown meat ( Katz-Rosene and Martin, 2020 ), 3D bioprinting ( Chua, 2020 ), and genetic engineering with CRISPR technology ( Zhang et al., 2020 ).

There is a lack of consensus on the societal, environmental, and economic implications of these technologies ( Bronson and Sengers, 2022 ). In the case of lab-grown meat, studies have shown that lab-grown meat will have a long way to go to replicate the micronutrient composition, the variety and diversity of breeds and cuts, with more research needed on the systems impact of the production, as well as its cultural and ethical implications ( Chriki and Hocquette, 2020 ). Recently, a group of interdisciplinary scholars have called for a more critical social science approach to foster more equitable and responsible agri-food innovations. Fielke et al. (2022 , p. 151) wrote of the need to “expand disciplinary boundaries so that social scientific imagination and practice are central to quests for ‘responsible' digital agri-food innovation”.

While the growing body of critical social science scholarship on digital agriculture and the fourth agricultural revolution, smart agriculture, and agri-tech approaches on Earth has grown substantially ( Fielke et al., 2022 ), the same call for responsible innovation in food studies has not yet covered food production in space and associated claims of benefit for earth. This presents an important area for academic inquiry because many of the same technologies, corporations, venture capital investors, and purported “win-win” solutions that are claimed for Earth are rapidly expanding into the space domain.

Terraforming: Learning from history and past failures

When it comes to developing new agri-food technologies for long-distance space missions and establishing human settlements it is critical to learn from past failures. To learn from the history of the green revolution, means to understand the “active erasure of alternative visions and vast diversity of agrarian practices” globally, by a single technology-centric hegemonic discourse which invokes the logic of “inevitability” ( Ajl and Sharma, 2022 , p. 419). Nowhere is this more central in the context of food and space than the lessons learned from Biosphere 2. Roberts (2007) uses the failure of the Biosphere 2 project as an important cautionary tale for the future of space missions. Biosphere 2, established in 1991, was an effort by Space Biospheric Ventures to develop a closed ecological system with 5 distinct biomes including rainforest, ocean, desert, marsh and grasslands. Within the Biosphere 2 system, eight settlers (Biospherians) would live for 2 years without the ability to call upon outside support. The experiment sought the goal of answering “whether man can design and live in a self-supporting biosphere in which the environment provides everything for life” ( Dewdney, 1997 , p. 125 as cited in Roberts, 2007 ). There were profits and investments to be made in developing technologies for closed ecological systems that enabled people to easily control and manage nature. When established, the site was proclaimed “the forefront of the futuristic ventures of space travel and colonization” ( Roberts, 2007 , p. 217). Unfortunately, Biosphere 2 failed its missions shortly after commencing as oxygen had to be added due to air quality deterioration. The Biospherians also became ill, and the animals in the biomes died, with some species even going extinct within the Biosphere ( Roberts, 2007 ). The drive to simplify, quantify, and reduce the complex functioning of the natural environment into a single “Biospheric Number” to better control nature failed ( Roberts, 2007 ). Several scholars have identified ways that Biosphere 2 could have been improved and how these lessons learned can help as an analog to support settlement success on Mars and long-duration space missions ( MacCallum et al., 2004 ).

While astronauts on the ISS can rely on regular shipments of food, to grow food on a celestial body like Mars may require some form of Terraforming. Terraforming can be defined as a process whereby people modify the surface and the atmosphere of a planet to make it suitable for human life ( Genta, 2021 ). In the article “Terraforming and Colonizing Mars”, Genta (2021) identifies that to colonize other planets, it is first imperative that scientists create artificial enclosed environments for people to live and cultivate food because even the most extreme environments on Earth do not replicate the harshness of the Martian surface. It is estimated that terraforming Mars would take centuries and a significant amount of investment. While centuries may seem long for the process of transforming Mars into a habitable place for human colonies, this temporal scale is many orders of magnitude less than it took for Earth—estimated to be 4.5 billion years old—to become supportive of complex life. Yet when it comes to Mars, there is an expectation that we should be able to terraform and settle the planet and establish the first human colony by 2050 ( Martin, 2021 ).

The extreme landscape of Mars cannot be compared to the deserts of MENA or the tundra of the Arctic. The Martian soil (regolith) contains elements that make it difficult for crops to grow. For example, regolith contains large amounts of highly toxic perchlorates and is hydrophobic, repelling water on contact ( Wamelink et al., 2021 ). While the latter can be addressed by worms on Earth, it is unclear if this can be replicated on Mars. Regolith is not currently available to be tested for food production. However, NASA has simulated regolith (called a regolith simulant) based on data gathered by the Mars Pathfinder rover and the Viking landers, albeit not exactly the same composition ( Wamelink et al., 2021 ). Without soil, a hydroponic approach to growing food may be possible. Hydroponic cultivation requires a growing medium such as rock wool. However, rock wool must be replaced after a few crop cycles and therefore would need resupply shipments from Earth ( Wamelink et al., 2021 ). While cultivation of crops with Mars regolith ( via the simulant) is possible in principle, there are many gaps that still need to be considered ( Wamelink et al., 2021 ). There is, of course, the lack of pollinators which cannot fully be replaced with drone pollinators, and cosmic radiation which is significantly higher on Mars than on Earth because it lacks a magnetic field and protective atmosphere, among many other issues. One clear thing is that human feces from the colonists will be a central to enriching the Martian soil enough to grow food—requiring time and numerous crop cycles ( Wamelink et al., 2021 ).

Similar to the critical issues that were raised around equity and the need for responsible innovation ( Fielke et al., 2022 ), it is interesting to note how the aspiration for multiplanetary living or human settlement on Mars engages language premised on the violent and extractive Columbian colonization of the Americas. For example, in discussing how to transform the atmosphere so that humans do not need to carry oxygen bottles and masks, Genta (2021 , p. 13) writes:

…Mars could one day have a breathable atmosphere and a flora and a fauna similar to Earth's, albeit adapted to the local environment. The planet could support a population of several million humans within a time similar to that which separates us from the arrival of Christopher Columbus in America. Mars would then be the first planet to be terraformed by colonizers from planet Earth.

The mobilization of colonial language via a techno-optimist approach to justify the plan for human settlement on Mars is deeply problematic. It demonstrates that the history of colonization is apt to be repeated through extractivism, exploitation, and profiteering. This study argues that it is critical to better understand the claims around Mars and Lunar settlements as the new frontier for agri-food innovation, especially as it pertains to capital ventures and investments and the mobilization of a colonial worldview. This is particularly important because it has been claimed, but not proven, that such developments will benefit Earth and its inhabitants.

Content analyses of media articles on food

Media articles examining coverage on food systems and its impact on climate change have identified the role of newspaper coverage on influencing potential responses by government and industry ( Neff et al., 2009 ). For example, analysis of newspaper coverage of “Meat Free Mondays” campaign have led to what Morris (2018) argued as an efficient approach in supporting de-meatification. However, as of the writing of this paper, there are no studies that have investigated news representations of agricultural technologies in space. As such we expanded the scope of our literature review to include news analyses of other specialized scientific topics. The existing literature we identified typically used variations of content analysis, a research technique that measures latent meanings embedded within texts. Content analysis techniques are expected to adhere to empirical standards of replicability and validity ( Krippendorff, 2004 , p. 18). News media research ranged from quantitatively rigorous, as in Rickard and Feldpausch-Parker (2016) study of aquaculture technology, to more qualitative meditations, like Pasquinelli and Trunfio (2020) narrative analysis of overtourism in cities and Augoustinos et al.'s (2010) discourse analysis of genetically modified food coverage. Some research embraced computerized analysis, like Danner et al.'s (2022) application of natural language processing to study news representations of organic food. Importantly, all these approaches ground themselves in the agenda-setting function of the news media, which tells audiences what to think about by selectively choosing topics to cover and topics to ignore ( McCombs and Shaw, 1972 ). Agenda-setting theory also assumes a social-constructionist perspective. Social issues do not exist until someone draws attention to them ( Hansen, 2019 , p. 15). The news media speaks (or does not speak) these issues into existence. With all of this in mind, we proceeded with a “middle of the road” content analysis and discourse analysis.

This study seeks to understand how the topic of food growth in space is reported in media. News stories about food growth technologies rarely break into mainstream news publications and usually remain in specialized publications like Farm Press and Agriculture Week . The ongoing development of smart farming and agricultural technology in space represents an opportunity for inquiry because, unlike other agricultural advancements, these are regularly covered in the news, especially in publications that are oriented toward tech coverage. Despite this, examples of previous news analysis research on food growth technologies are sparse. In comparison to the interrelated issue of climate change, which has seen numerous news media analyses, whether it be on social media analysis of climate change ( Pearce et al., 2019 ), on climate change technologies in US media ( Stephens et al., 2009 ), or a comparative analysis of newspaper coverage of climate change in 27 countries ( Schmidt et al., 2013 ). It is interesting to see the lack of attention to media framing of agricultural technologies since many of these technologies are claiming to support climate change mitigation and adaptation ( Adamides et al., 2020 ). More importantly, the industrial agricultural food system that is highly dependent on fossil fuels and concentrated animal feedlots is one of the top contributors to climate change ( Horrigan et al., 2002 ). However, social media analysis of the future of smart agriculture ( Ofori and El-Gayar, 2019 ) and precision agriculture ( Ofori and El-Gayar, 2021 ) do exist. One preprint analysis of media coverage of digitalization in agriculture found pro-digitalization arguments to be predominant in the media ( Mohr and Höhler, 2021 ). This finding is important as this positive framing shapes public perception and the facilitation of policies that further support digitization.

Materials and methods

To capture a cross-section of present-day news media discourses, we searched for English language articles published in the United States, Canada and the United Kingdom between January 1, 2019, and April 15, 2022. This timeframe covers a significant amount of time before and after the launch of the Deep Space Food Challenge in January 2021 ( Hall, 2021 ), which we previously identified as a turning point of news coverage on this topic (see Figure 1 for frequency distribution of articles in sample). To identify a sample of articles, we used Google Search and Factiva. Google Search provided access to web-only news (i.e., Space.com, Forbes, and Yahoo). Factiva was used to access print publications. Factiva does have a web news search function, but in testing we found it to be unreliable, at times missing articles from major online publications and with a steep drop-off in texts older than 90 days at the time of the search. The search engines complemented each other—in one success, Google returned two Scientific American articles that Factiva could not find, while Factiva identified a print-only article from the same publication that was not available on Google. Constructing a meaningful and robust set of articles was challenging given the specificity of our topic and the coincidence of ultimately irrelevant articles written with relevant words (for instance, preliminary searches often returned articles about Mars Inc.'s food and candy technology innovations). In Factiva, we wrote a complex Boolean search string and used filters to eliminate as many irrelevant articles as possible. In Google, we used a comparatively simple search string to identify all possible relevant articles. This returned 413 unique articles (Google: 209; Factiva: 204), which were downloaded for further processing. After skim-reading article titles and first paragraphs for relevance, the final sample was refined to 170 unique articles (Google N = 109; Factiva N = 61) published by 67 English publications. Of the 170 articles in the sample, a random sample of 40 articles was selected for an intensive deep reading process. All articles were then converted from PDF to TXT format and imported into NVivo for quantitative analysis.

Figure 1 . The distribution of articles by date of publication, annotated at points of interest. A trend line shows a slight overall increase in coverage over the time period, although this increase is not statistically significant ( p = 0.24).

Factiva Boolean search string:

(food or crop or crops or mycology or agricult * )/F100/ and ((technology or technologies) and space) and (((((“Mars” not (“Mars Inc” or incorporated or “accelerator fund”)) or (space and NASA)) or (“space travel”)) or (((terraform or terraforming) NOT (“Terraform Labs” or HashiCorp or registry or “cloud data” or AWS “Terraform Cloud” or Cisco or gaming or movie))))) not (“pet food” or “pet foods”) not daybook.

Mixed methods content analysis

We first conducted a series of iterative deep readings on 40 randomly selected articles to inductively generate broad categories to organize data within. Borrowing from Thematic Analysis (TA), we searched for themes that “represent[ed] some level of patterned response or meaning within the data set” ( Braun and Clarke, 2012 , p. 82). We collaboratively read articles, paying special attention to latent or hidden meanings within the texts, eventually identifying three major themes for analysis: Earth connection, private/public collaboration and funding , and “ soft news approach .” During the deep reading process, we kept track of the “players”—technologies, people, and organizations—which informed the quantitative analysis process. Wherever possible, we supported findings discovered during the qualitative deep reading process with quantitative evidence by applying word frequency analysis to the entire sample of 170 articles.

The computerized word frequency analysis for this project was designed after the themes, technologies, and other data of interest were determined in the qualitative deep reading process. As elaborated by Krippendorff (2004) , a research design using computerized analysis only approximates the intensive qualitative processes it is based upon. Computerized analysis is most powerful when searching for denotative meanings but falls short when tasked to interrogate latent meanings. It must be combined with a qualitative analysis process to draw meaningful conclusions. As such, thematic categories were developed without the use of computerized word frequency because of their relative linguistic complexity. Further development of natural language processing software is necessary to make future computerized thematic news analysis possible. During this stage of analysis, we used the word frequency search function in NVivo to capture the relative prominence of each search term. Articles were scanned only for the presence of the search term and not the number or intensity of references within.

The manual deep-reading process was used to inform and calibrate the computerized word frequency search process. Relevant articles were scanned for the types of agricultural technologies mentioned. Searching for specific technologies was challenging because of the many names used to refer to a group of colloquially synonymous technologies. For example, lab-grown meat can also be known as synthetic meat, synthetic protein, cultured meat, synthetically grown meat, in vitro meat, and others. Technologies with multiple names were combined into a single category for the word frequency searches. This process was not necessary to analyze mentions of people or companies, which did not have the same level of colloquial variance as the technologies did. As such, a reliability figure is provided only for the technologies category. The technologies identified per article during deep reading and technologies identified per article from computerized word frequency search were positively correlated, r (15) = 0.72, p < 0.01, indicating that the computerized word frequency searches returned results sufficiently similar to the deep-reading process (the variance between these measures is visualized in Figure 2 ).

Figure 2 . Bar chart showing the percentage of articles in both the deep reading and word frequency analyses that reference a specific food growth technology, further categorized by type of technology (plant cultivation, non-plant cultivation, and assistive growing technologies). Type totals are displayed on the separate bar chart to the right. Variance between the deep reading analysis and computerized word frequency analysis is depicted using whiskers and the mean of these two measures is depicted in the blue bars.

Food production technologies for space

The history of space agricultural research in the early 50s and 60s primarily focused on algae ( Wheeler, 2017 ). However, despite some early promise, researchers found it difficult to convert algae into palatable foods and some contain a significant amount of indigestible cell wall, as well as phytotoxic volatiles ( Wheeler, 2017 ). Decades of research have resulted in new technologies being tested for long-duration space missions and are highlighted in the media articles we reviewed. One of the key research objectives of this study is to better understand and identify the types of agricultural technologies featured in media articles on food and space. The types of technologies featured in the news media may reflect new innovations, applications, and adaptations of Earth-based growing technologies for space purposes.

As noted in the Deep Space Food Challenge, technologies developed for space travel require more automation in a controlled environment to free spacefarers for more important tasks. As Figure 2 and Table 1 depict, the high proportion of articles (59%) addressing plant cultivation technologies was to be expected due to decades of research on growing vegetables with LED lighting systems ( Cathey and Campbell, 1980 ) and hydroponic cultivation ( Resh, 1989 ). In the recent decade, the “Veggie” hydroponic growing system has gone through various iterations to test agriculture in space. Veggie is a plant growing chamber developed by ORBITEC to provide a low-mass, low power, and low crew-time system to produce fresh vegetables in space ( Massa et al., 2017) . Beyond growing food, the benefits of the Veggie system include the behavioral health benefits of enabling astronauts to cultivate and eat fresh space crops ( Massa et al., 2017 ). The first Veggie system was sent to the ISS in 2014 using the SpaceX capsule. Massa et al. (2017) noted that historically, space flight food growing experiments have had challenges delivering fluid and oxygen to plant roots. VEG-01 required continuous crew involvement to care for the plants, which did not meet design expectations. Iterative development of Veggie plant growth systems continues today, with VEG-03 being launched in 2016 ( Massa et al., 2017 ). Hydroponic growth technology was among the most frequently mentioned of any food technology in the corpus.

Table 1 . Specific references to food growth technologies, grouped by deep read analysis frequency and quantitative analysis frequency.

Aside from plant cultivation technologies, an alternative technology mentioned as frequently as hydroponics was synthetic protein and cultured meats. In 2019, the first synthetic meat was grown from cells in the ISS ( Kooser, 2020 ). News media articles about this technology repeated its claimed potential to use fewer resources, as well as its value as an investment opportunity. For example, in talking about space opportunities, the article cited the valuation of the alternative meat sector:

Barclays predicts the alternative meat sector could reach about $140 billion in sales over the next decade, with companies like Impossible Burger and Beyond Meat leading the charge.

—( Lewis, 2019 )

It is important to note that these synthetic/lab-grown meats are also tied to assistive technologies such as 3D Bioprinting to assemble the muscle tissue developed in vitro in the lab, to mimic the shape and texture of regular meat.

Throughout the manual coding process, we identified the individuals and organizations featured in each article. This preliminary identification process guided word frequency analysis which scanned all articles in the corpus. This analysis captures a cross-section of the conversation happening about growing food in space. Astronauts, researchers, and company leaders were featured most prominently, with a few additional references to people of other professions (categorized as “other”) (see Figure 3 ).

Figure 3 . People mentioned in five or more articles in the word frequency analysis, showing primary occupations (astronaut, researcher, company leader, and other).

Despite the news-making tendencies of tech company leaders, this study found that astronauts and researchers remain the stars of the show. Astronaut Scott Kelly was mentioned in more articles than any other person in the study. In 2015, Scott Kelly, Kjell Lindgren, and Kimiya Yui harvested the first batch of romaine lettuce ever grown in space ( Rainey, 2015 ). This widely publicized harvest preceded our data collection by 4 years but was nonetheless mentioned as background in many articles published thereafter. Scott Kelly later announced the winners of the Deep Space Food Challenge alongside celebrity chef Martha Stewart ( NASA, 2021 ), who herself ranked among the most frequently mentioned people in the study. Mobilizing “star power” and influencers builds the excitement around growing food for space and promotes the Deep Space Food Challenge. For example, one article published in Space.com led with the title “Martha Stewart helps NASA pick Deep Space Food Challenge winners.” These types of articles are designed to appeal to the public because while many may not be familiar with the names of astronauts or researchers, they may immediately recognize Martha Stewart, reminiscent of a contemporary two-step flow ( Katz, 1957 )— because Martha Stewart cares about space, the public should too .

Researchers also ranked highly. NASA scientists Dr. Gioia Massa and Dr. Matt Romeyn, who worked on the hydroponic Vegetable Production Systems (“Veggie”), were frequently mentioned. Like Kelly, Massa and Romeyn were often quoted for their work on the 2015 space lettuce story, but also received coverage for more recent successes, including the growing of peppers, radishes and bok choy in space. Massa was the most frequently mentioned of any woman in the study by a significant margin, being mentioned in 15 articles. NASA researcher Nicole Dufour and astronauts Megan McArthur and Christina Koch were referenced in 6 articles each. Company leaders mentioned in the articles were dominated by four men: Elon Musk of Space X, Didier Toubia of Aleph Farms, Jeff Bezos of Blue Origin, and Richard Branson of Virgin Galactic. Of all companies tracked in our research, only one female company leader—Founder and CEO of Air Protein Dr. Lisa Dyson—was mentioned in more than one article.

Private/public partnerships

When it comes to the role of the private or public sector, we were interested in understanding the public or private bodies that contributed to the overall effort (see Figure 4 ). Predictably, NASA dominates news coverage of food growth in space, with 77% of articles mentioning NASA at least once. The Canadian Space Agency (CSA) and European Space Agency (ESA) follow in a distant second and third place, with various universities, research institutes and government agencies ranking below.

Figure 4 . Public and private organizations mentioned. Bar chart showing proportion of articles in the word frequency analysis referencing a specific organization, separated by public/not-for-profit and private companies. Chart has been scaled down to better show variance in organizations with fewer references than NASA, which was referenced 3.8× more often than the second most-mentioned organization.

In the private sphere, SpaceX receives vastly more coverage than any other company (20% of articles), although still overshadowed by NASA's looming presence. Ranking below SpaceX was a mixture of fledgling and established companies. Aleph Farms, an Israeli synthetic protein startup founded in 2017, seemed to punch far above its weight, earning more coverage than any company besides SpaceX. Heinz was mentioned in seven articles (4%) for its Marz Edition ketchup, which was produced with tomatoes “grown under Mars-like conditions”. The Marz Edition ketchup is representative of a larger trend we identified of non-space companies competing in the industry. Like Heinz, Tupperware and Hilton have both funded food growth experimentation in space, earning media attention along the way. All identified companies in the study, with the notable exception of Aleph Farms, emphasize their symbiotic relationships with NASA. Private-public partnership is common within the field, rooted in the foundations of the US space industry ( Launius and McCurdy, 2018 ). NASA incentivizes private firms to contribute to the agency's objectives, thereby distributing risks and reducing direct costs ( NASA, 2004 ). Incentivizing private ventures in space technology also reduces red tape, lowers barriers to entry and facilitates innovation, but some scholars have noted the need to ensure international space laws or legal regimes that would assure the sustainability of space explorations amidst the growing privatization of space ventures ( Iliopoulos and Esteban, 2020 ). Currently, private ventures in space exploration are depending on a breakthrough in agricultural technology to make comfortable space tourism a reality. As one article noted:

To date, the design of space food has rightfully focused on nutrition and convenience, as the majority of spacefarers have been government astronauts with scientific mission objectives. However, for space tourism to gain traction among the ultra wealthy, space vehicle operators must begin thinking of their flights as a premium passenger experience rather than a set of minimum requirements.

—( Kiang, 2020 )

Word frequency analysis shows that NASA dominates the conversation. Similarly, of the deep read sample, 38% of articles referenced only public institutions, 48% of articles indicated a public-private partnership, and 13% referenced only private entities (see Table 2 ). Of the articles that referenced both private and public institutions, the connection was often unidirectional. There were several instances of private companies “namedropping” NASA, even if they were not in direct collaboration with the agency. This type of reference might lend legitimacy to start-ups looking for favorable news coverage. For example, the synthetic meat start-up Air Protein carefully attributes only the “inspiration” of their product to NASA technology:

Air Protein leverages carbon transformation technology developed by Kiverdi, which was inspired by NASA's closed loop carbon cycle concepts for long-journey space missions. The protein found in air-based meat is produced using natural processes, and made completely free of any use of pesticides, herbicides. hormones or antibiotics.

—( Air Protein, 2019 )

Table 2 . Number of articles in the deep read analysis that referenced only public entities, a public-private partnership, only private entities, or that were excluded from the statistic.

Similarly, an article may also leverage the role of the private sector in supporting NASA's mission:

NASA has said that they hope to send the first humans to Mars by the mid-2030s, spurred on by private sector billionaires such as SpaceX's Elon Musk.

—( Sparks, 2021 )

Finally, companies often claimed that developing space agriculture technologies will increase profitability on Earth. One article about Tupperware Brands put it this way:

NASA needs its astronauts to grow food as the length of space missions increase to reach the moon and Mars. The project could also help Tupperware make money on Earth.

—( Fuller, 2020 )

Earth connection: Good for space, good for earth

During preliminary readings of the corpus, we recognized that articles often include at least one sentence on how the development of agricultural technologies in space can contribute to climate resiliency, sustainable agriculture, and address other contemporary food growth challenges on Earth such as food insecurity. Government funding of space travel has long been a controversial matter, frequently critiqued by the public as frivolous ( Steinberg, 2011 ). NASA is usually among the first government organizations to face scrutiny when the specter of federal budget cuts periodically re-emerges ( Steinberg, 2011 ), so its spending must occasionally be justified to the public. Although not as sensitive to public opinion, private companies like SpaceX are similarly subject to negative public opinion, especially concerning costs ( Platt et al., 2020 ). Our deep read analysis found that 73% of articles on food production in space made at least one overt connection to the claimed benefits of the technologies for Earth (see Table 3 ). The remaining 27% of articles made no connection of these issues, and usually limited discussion of the technological development to space only. The latency of this theme meant that only qualitative analysis was possible, and in lieu of quantitative reinforcement, we have highlighted a few examples of the theme in action.

Table 3 . Number of articles in the deep read analysis containing an earth connection reference.

To justify the spending, private and public entities alike appeal to the trickling down of space technology as something that directly benefits the inhabitants of Earth. News articles uncannily reflect this careful messaging. Whether it is the use of fewer resources, the challenge of growing food amidst extreme environments precipitated by climate change, or addressing acute food emergencies, there are many claims raised in the media about the Earth implications of these endeavors, all of which have been framed largely through a positive light. For example, lab-grown meat has been purported to save water and preserve natural resources:

“The space-grown meat could help feed astronauts during long-term manned space missions, as well as address food insecurity among a booming population down on Earth, according to a statement from 3D Bioprinting Solutions”… “In space, we don't have 10,000 or 15,000 liters (3,962.58 gallons) of water available to produce one kilogram (2.205 pounds) of beef,” said Toubia in the Monday press release. “This joint experiment marks a significant first step toward achieving our vision to ensure food security for generations to come, while preserving our natural resources.”

—( Yeung, 2019 )

Media sites frequently publish articles that frame a deep space diet as more sustainable and ethical than what is currently available on earth:

The researchers said research on how to feed Martians could also help feed people on Earth. “The constraints imposed by Mars—a cold, thin atmosphere—force you to produce food in ways that are actually more sustainable and ethical than what's done on Earth with current factory-farming practices,” Cannon said. “So, switching to a 'Martian diet' can help our planet.”

—( Choi, 2019 )

It's inevitable: Soft news on space food technology

The final theme we identified was a soft news approach, or an uncritical reporting of space food technology and its implications for earth. During the intensive reading process, we coded articles as being generally positive, neutral, or negative in tone. An overwhelming majority of articles were marked positive (88%), and only one was marked as negative (3%). Preliminary sentiment analysis using Language Inquiry and Word Count software (LIWC) ( Pennebaker et al., 2015 ) supported this finding, signaling that this was a vein for future exploration, although final statistical analysis using the software was inconclusive. The use of positively-affective language or subject matter in news articles is a typical marker of “entertainment news” writing ( Harcup and O'Neill, 2001 ). However, reading further, we realized that this theme was not as dichotomous as positive/negative. Rather, it is about how news media organizations tend to report space food technology news uncritically, recycling press releases, tweets, and other information directly from the source, potentially leading the reader to a positive impression of the subject. The result is an overwhelming proportion of space food technology articles being reported as “soft news”, being only “either personally useful or merely entertaining” ( Zaller, 2003 , p. 129), and not being reported for the sake of providing accurate information about the feasibility and consequences of such technology, as readers might expect ( Baum and Jamison, 2006 ). This mode of representation uncritically promotes the technology, reflecting the attitude that a multiplanetary humanity is inevitable—a position that benefits industry stakeholders. This theme was the last we developed, in part, because we could only recognize it after becoming familiar with the entire corpus. In lieu of a computerized or other statistical processes to validate these findings, which was not possible for such latent meanings, we provide a brief discourse analysis to better depict this theme.

Despite ample opportunities to point out gaps in the research, reporting on space food development remains uncritical. Uncritical reporting of space food technology are of particular benefit to companies and organizations looking to market their product as a positive good because it accepts without question that the technology will eventually benefit humans on Earth. Put succinctly in one article in The Star,

Anything that's good for space is going to be great for Earth

—( Weber, 2021 )

The articles in the sample seldom refute this notion, which is often parroted from a company or organization spokesperson. Moreover, the question of “who benefits?” is not raised at all. Of all articles in the intensive-reading sample, only one was noted as being critical ( Dvorsky, 2019 ). While this lone article highlighted the numerous challenges of growing food for human settlements in outer space or long-duration space missions, the rest turned to soft news tendencies—humorous quips, clichés, and comparisons to the banality of everyday life on earth. Over-coverage of space food developments using “everyday mundane” human activities and clichés may result in a lack of critical perspective. One only needs to look at the concluding sentences or claims of some of the articles to see the clichés in action:

The Martian ketchup is not available for purchase, but if you ever find yourself heading to Mars, that might be one thing you don't have to pack.

—( Liang, 2021 )

We may be many long years away from hosting BBQs on Mars, but the vision for growing off-world meat is already in place.

—( Kooser, 2020 )

The framing of food growth in space as merely a scientific novelty or oddity reveals itself in these quips but is present throughout almost all reporting on these technologies. Our finding indicates that news coverage on this topic employs a “hybrid” reporting model which blends factual news and entertainment ( Edgerly and Vraga, 2019 ), supporting other scholarly literature that points to an increasingly hybridized news media ecosystem ( Mast et al., 2017 ).

Who gets to speak for the earth about the food and space frontier?

The idea of a “new agricultural frontier” is not new. Whether it is the “New World” plantation frontier with the colonization of the Americas and the Caribbean ( Mintz, 2011 ), the “green revolution” frontier which was mobilized all across the global South ( Patel, 2012 ), the “arctic frontier” spurred by climate change ( Bradley and Stein, 2022 ), or the growing landgrab in the “African frontier” ( Cotula, 2013 ), the “Space and Food frontier” is but another stage in a long line of new food frontiers. However, despite seemingly being disparate from the other frontier stories and moving beyond terrestrial boundaries, 73% of the news media articles analyzed in this study directly connected growing food in space to our ability to solve food-related issues faced on Earth.

Whether to help solve food insecurity, adapt to climate change, or address the ill effects of industrial animal agriculture, none of the claims about space food solving Earth's problems address the deeper underlying issues that have resulted in what many scholars have noted as a neoliberal paradox of hunger amidst plenty ( Patel, 2007 ). We found that systemic and structural problems in the food system such as racism ( Alkon and Norgaard, 2009 ), settler colonialism and the continued occupation of Indigenous lands ( Wolfe, 2006 ; Stollmeyer, 2021 ), and economic systems that commodify food, suddenly become problems for technology to solve. In essence, the claim that “whatever is good in space is good for Earth” is disconnected from the reality of food injustice, the impact of colonial imperialism and growing corporate power on Earth ( Clapp, 2021 ) and the problem of worldview. As we have shown, news media participates in this process through uncritical reporting.

The search for a new frontier for food terrestrially is often framed according to the projected challenge of feeding billions more people. But as noted in the media articles and the literature review, we are now moving this challenge toward feeding a multiplanetary society. Musk, one of the top names mentioned in the private sector, has not only clearly stated the goals to develop settlements in Mars, but the company has gone as far as to assert its vision of “making humanity multiplanetary” ( Space, 2022 ). But what does multiplanetary mean and who gets to speak for Earth as it pertains to food and food sovereignty? These are important considerations when promoting the various technologies, in light of the active ongoing debate around the governance of artificial intelligence and the digitalization of agriculture ( Ryan, 2022 ), research on the ethics, as well as the promise and peril of cultured meat ( Chriki and Hocquette, 2020 ; Newman, 2020 ), and the questions around the patenting of food through biotechnology ( Carolan, 2010 ). The news media does not appear to be asking these questions in any meaningful capacity. Many articles appeared to parrot press releases and marketing material from both public and private entities. Aleph Farms, a synthetic protein company, was the subject of 13 articles in the full sample. Each article adheres tightly to the language written in the company's press releases—proudly touting their “3D Bioprinted Space Beef”. The company relies on the oddity of space travel, even though the business is done on Earth. Similarly, a single tweet from NASA astronaut Megan McArthur about hydroponically grown chili peppers being used to spice “space tacos” on the ISS spurred twelve articles alone in the corpus.

When it comes to the public good, as Patel (2009) noted, key to food sovereignty and food security is direct democratic participation, and peoples' rights to shape food policy. In essence, who gets to speak matters. This paper found that in the body of the corpus, the majority (48%) of the articles focused on featuring public and private collaboration, with the next being focused on featuring universities and space agencies (38%) and comparatively few focused solely on promoting only private companies (13%). In seeming tension to some of the messaging around solving food insecurity for the earth, the articles reviewed also laid bare profit motives and the courting of investments for space tourism. As mentioned in one of the articles, growing food in space is not just going to be about meeting the bare minimum of nutrition or dietary requirements for astronauts, with the view on space tourism for the ultra-wealthy, growing and making food also means thinking about creating a “premium passenger experience” ( Kiang, 2020 ).

Some of the findings around the individuals identified in the media articles represent some small successes regarding gender diversity in space technology development. Two of the five astronauts in Figure 3 identify as women—a proportion much higher than the 11.4% of astronauts globally who identify as women ( Smith et al., 2020 ). Gender representation among researchers is split similarly, with two of four people in Figure 3 identifying as women, representing a higher share than the overall STEM gender gap in the US ( Wang and Degol, 2017 ). Despite these successes, more progress needs to be made to close the gender gap in space agriculture technology development, and nowhere is this need more evident than in company leadership which were dominated by four men: Elon Musk of Space X, Didier Toubia of Aleph Farms, Jeff Bezos of Blue Origin, and Richard Branson of Virgin Galactic. This finding highlights the gendered nature of private investment in space endeavors.

The vast majority of articles within our sample resemble the structure of entertainment or hybridized news ( Harcup and O'Neill, 2001 ; Mast et al., 2017 ), rather than that of a hard news event about a technological discovery, as a reader might expect. The stories often focus on the people behind the technology (especially the charismatic astronauts) rather than the technology itself. This “human interest” framing of food production in space may trivialize the issue, given that human interest stories are typically “read merely for their own intrinsic interest with relatively slight reference to the actual world of people and events in which they occurred,” ( Hughes, 1980 , Introduction). The novelty and potential virality of “Martian ketchup” and “space bacon” makes these stories extraordinarily valuable to both print and online publications ( Harcup and O'Neill, 2001 ; Al-Rawi, 2019 ). These articles fall distinctly into the category of soft news , which is identifiable by its timelessness, political irrelevance, and personality ( Reinemann et al., 2012 ). As such, very few of the space food articles exemplified any sort of critical reporting. The lack of criticality works in the favor of billionaires looking for a return on their space industry investments while missing a golden opportunity to spotlight issues of food access and sustainability on Earth.

Limitations

We faced numerous challenges with data collection. Despite Factiva having a web news search function, we found its web news catalog to be unevenly populated, at times missing articles from major online publications and with a steep drop-off in texts older than 90 days at the time of the search. We used results from Google to balance this, ultimately creating a corpus that is comprehensive of articles published on space food technology within our timeframe. However, our study focused on Anglocentric news publications, likely privileging coverage of organizations like NASA and SpaceX. As our research shows, most of these publications report favorably on the unfounded and sometimes colonially-tinged aspirations of the space agricultural industry—it is well-reasoned to question if this attitude is replicated outside of the anglosphere.

Furthermore, while we believe our chosen mixed methods analysis is best for the size, scope, and content of the articles in our sample, we suggest that the quantitative portions of this project could be made more accurate with a full-scale manual framing or content analysis. Doing so would require more funding than we had access to, mostly to employ human coders. In lieu of this, we legitimize and support our findings with data derived from computerized word frequency searches wherever possible.

This paper analyzed how news media articles have presented the issue of food production for long-duration space missions, and more specifically, what specific technologies and stakeholders are being discussed. The majority of articles in the sample were positive in tone and failed to critically engage the claims of purported benefits to Earth's inhabitants. Only one article of the 40 in the qualitative deep read sample brought up significant concerns about the sheer amount of financing that would be needed and the time it would take to make Mars habitable. SpaceX aims to build a settlement on Mars for 1 million people by 2050, but the scale of development required for such a settlement is tremendous. Dreams of a terraformed Mars overpromise our technological abilities—existing literature on terraforming pointed to Earth, of which the vast majority of its 4.5-billion-year history was not habitable for humans, to illustrate the lack of hubris expressed when making claims about terraforming Mars.

A key theme in the study is the lack of criticality and the “soft news” approach of the articles when promoting the claims that the research and development of food production for space will result in earthly benefits. The benefits covered in the article range from world food security, to addressing climate change, to improving animal welfare, ethics and more. However, the claims in these news media articles were made without considering the ongoing debates and concerns raised by social scientists surrounding the technologies themselves, nor did they challenge the techno-optimistic romanticization of the technologies.

We also found that despite astronauts being an important voice featured in the articles, both leaders of private companies and celebrities like Martha Stewart featured prominently in many of the articles. More importantly, many of the articles included information about market valuation and the case for investment in these companies. People persuaded to invest by the positive news coverage and promises of Earth benefits may not see the entire picture.

Although there is a substantial amount of literature on the technical and scientific aspects of food production in space and on designing the spacefarer's eating experiences ( Obrist et al., 2019 ), there is a lack of critical social science studies on this “new frontier” of food systems research. We commonly see environmental issues linked to food production as being frequently politicized and subjected to news media agenda-setting but find that the subject suddenly reported in an uncritical manner when it takes place on a spaceship or celestial colony. In the future, we call for further research on matters of equity, gender, governance and the investigation of who speaks for the Earth when it comes to establishing extraterrestrial human settlements. We also recommend that journalists and news reporters interrogate whether technologies developed for space actually have practical applications on Earth. A critical social science approach to the political economy behind the financialization of space food research would also be of benefit. To conclude, when it comes to the technologies for growing food in space, whether it be Artificial Intelligence, machine learning, robotics and more, we agree with the recommendations noted by Fielke et al. (2022) . Fielke et al. (2022) identified the need to expand disciplinary boundaries to ensure that social scientific imagination and practice are central in the quest for responsible for digital innovation. Our study calls for the responsible framing of agri-food space technological innovations in news media, and the contributions of more social scientists in research and conversations around producing food in space.

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Author contributions

Study conception, funding, and design: TS. Data collection: RS. Analysis and interpretation of results and draft manuscript preparation: RS and TS. All authors reviewed the results and approved the final version of the manuscript.

This study was funded by the Social Sciences and Humanities Research Council Insight Grant 435–2019-0155.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

About Blue (n.d.). Available online at: https://www.blueorigin.com/about-blue (accessed July 24, 2022).

Google Scholar

Adamides, G., Kalatzis, N., Stylianou, A., Marianos, N., Chatzipapadopoulos, F., Giannakopoulou, M., et al. (2020). Smart farming techniques for climate change adaptation in cyprus. Atmosphere 11, 557. doi: 10.3390/atmos11060557

CrossRef Full Text | Google Scholar

Air Protein (2019). News Release: Air Protein Introduces The World's First Air-Based Food . Berkeley, CA: Contify Retail News.

Ajl, M., and Sharma, D. (2022). The Green Revolution and transversal countermovements: recovering alternative agronomic imaginaries in Tunisia and India. Can. J. Dev. Studies Revue canadienne d'études du développement 43, 1–21. doi: 10.1080/02255189.2022.2052028

Alkon, A. H., and Norgaard, K. M. (2009). Breaking the food chains: an investigation of food justice activism. Sociol. Inquiry 79, 289–305. doi: 10.1111/j.1475-682X.2009.00291.x

Allen, T. (2014). “Costs and benefits of a northern greenhouse,” in Sustainable Agriculture and Food Security in the Circumpolar North , eds S. S. Seefeldt and D. Helfferich. Proceedings of the 8th Circumpolar Agricultural Conference and Inaugural University of the Arctic Food Summit . Fairbanks, AK: Alaska Agricultural & Forestry Experiment Station. 58–74.

Al-Rawi, A. (2019). Viral news on social media. Digit. Journal. 7, 63–79. doi: 10.1080/21670811.2017.1387062

Augoustinos, M., Crabb, S., and Shepherd, R. (2010). Genetically modified food in the news: media representations of the GM debate in the UK. Public Underst. Sci. 19, 98–114. doi: 10.1177/0963662508088669

PubMed Abstract | CrossRef Full Text | Google Scholar

Baum, M. A., and Jamison, A. S. (2006). The oprah effect: how soft news helps inattentive citizens vote consistently. J. Politics 68, 946–959. doi: 10.1111/j.1468-2508.2006.00482.x

Bourland, C. T., and Vogt, G. L. (2010). The Astronaut's Cookbook: Tales, Recipes and More. New York, NY. Springer . Available online at: https://link.springer.com/book/10.1007/978-1-4419-0624-3 (accessed September 24, 2022).

Bradley, H., and Stein, S. (2022). Climate opportunism and values of change on the Arctic agricultural frontier. Econ. Anthropol. 9, 207–222. doi: 10.1002/sea2.12251

Braun, V., and Clarke, V. (2012). “Thematic analysis,” in APA Handbook of Research Methods in Psychology, Vol 2: Research Designs: Quantitative, Qualitative, Neuropsychological, and Biological , eds H. Cooper, P. M. Camic, D. L. Long, A. T. Panter, D. Rindskopf, and K. J. Sher (Washington, DC: American Psychological Association), 57–71.

Bronson, K., and Sengers, P. (2022). Big tech meets big ag: diversifying epistemologies of data and power. Sci. Cult. 31, 15–28. doi: 10.1080/09505431.2021.1986692

Bychkov, A., Reshetnikova, P., Bychkova, E., Podgorbunskikh, E., and Koptev, V. (2021). The current state and future trends of space nutrition from a perspective of astronauts' physiology. Int. J. Gastron. Food Sci. 24, 100324. doi: 10.1016/j.ijgfs.2021.100324

Carolan, M. (2018). ‘Smart' farming techniques as political ontology: access, sovereignty and the performance of neoliberal and not-so-neoliberal worlds. Sociol. Ruralis 58, 745–764. doi: 10.1111/soru.12202

Carolan, M. S. (2010). Decentering Biotechnology: Assemblages Built and Assemblages Masked. 1st Edn. London: Routledge . Available online at: https://www.taylorfrancis.com/books/mono/10.4324/9781315576084/decentering-biotechnology-michael-carolan (accessed September 24, 2022).

Cathey, H. M., and Campbell, L. E. (1980). “Light and lighting systems for horticultural plants,” in Horticultural Reviews , Vol. 2, ed J. Janick (Hoboken, NJ: John Wiley & Sons, Incorporated).

Chen, A., and Natcher, D. (2019). Greening Canada's arctic food system: local food procurement strategies for combating food insecurity. Can. Food Stud. La Revue Canadienne Des Études Sur l'alimentation 6, 140–154. doi: 10.15353/cfs-rcea.v6i1.301

Choi, C. Q. (2019). How to Feed a Mars Colony of 1 Million People . Space.Com. Available online at: space.com/how-feed-one-million-mars-colonists.html (accessed September 24, 2022).

Chriki, S., and Hocquette, J.-F. (2020). The myth of cultured meat: a review. Front. Nutr. 7, 7. doi: 10.3389/fnut.2020.00007

Chua, C. K. (2020). Publication trends in 3D bioprinting and 3D food printing. Int. J. Bioprinting 6, 257. doi: 10.18063/ijb.v6i1.257

Clapp, J. (2021). The problem with growing corporate concentration and power in the global food system. Nature Food 2, 404–408. doi: 10.1038/s43016-021-00297-7

Clercq, M. D., Vats, A., and Biel, A. (2018). Agriculture 4.0: The Future of Farm Technology. Dubai: World Government Summit . Available online at: https://www.worldgovernmentsummit.org/api/publications/document?id=95df8ac4-e97c-6578-b2f8-ff0000a7ddb6 (accessed May 25, 2022).

Cotula, L. (2013). The Great African Land Grab?: Agricultural Investments and the Global Food System . New York, NY: Bloomsbury Publishing.

Danner, H., Hagerer, G., Pan, Y., and Groh, G. (2022). The news media and its audience: Agenda setting on organic food in the United States and Germany. J. Clean. Prod. 354, 131503. doi: 10.1016/j.jclepro.2022.131503

Deep Space Food Challenge. (n.d.). Deep Space Food Challenge . Available online at: https://www.deepspacefoodchallenge.org (accessed September 18, 2022).

Dewdney, A. K. (1997). Yes, We Have No Neutrons: An Eye-Opening Tour Through the Twists and Turns of Bad Science. New York, NY: Wiley.

Duncan, E., Rotz, S., Magnan, A., and Bronson, K. (2022). Disciplining land through data: the role of agricultural technologies in farmland assetisation. Sociol. Ruralis 62, 231–249. doi: 10.1111/soru.12369

Dvorsky, G. (2019). Humans Will Never Colonize Mars. Gizmodo . Available online at: https://gizmodo.com/humans-will-never-colonize-mars-1836316222 (accessed September 24, 2022).

Edgerly, S., and Vraga, E. K. (2019). News, entertainment, or both? Exploring audience perceptions of media genre in a hybrid media environment. Journalism 20, 807–826. doi: 10.1177/1464884917730709

Fielke, S., Bronson, K., Carolan, M., Eastwood, C., Higgins, V., Jakku, E., et al. (2022). A call to expand disciplinary boundaries so that social scientific imagination and practice are central to quests for ‘responsible' digital agri-food innovation. Sociol. Rural. 62, 151–161. doi: 10.1111/soru.12376

Fuller, A. (2020). Tupperware Aims for Future, Shoots for the Stars . Hamilton, ON: The Hamilton Spectator.

Garcia, M. (2016). NASA Station Astronaut Record Holders. NASA . Available online at: http://www.nasa.gov/feature/nasa-station-astronaut-record-holders (accessed September 24, 2022).

Genta, G. (2021). “Terraforming and colonizing mars,” in Terraforming Mars. 1st Edn , eds M. Beech, J. Seckbach, and R. Gordon (Hoboken, NJ: Wiley), 1–22.

PubMed Abstract | Google Scholar

Gohd, C. (2021). Why Jeff Bezos's Blue Origin is so Reviled. Scientific American . Available online at: https://www.scientificamerican.com/article/why-jeff-bezos-blue-origin-is-so-reviled/ (accessed September 24, 2022).

Hall, L. (2021). Deep Space Food Challenge. NASA . Available online at: http://www.nasa.gov/feature/deep-space-food-challenge (accessed May 25, 2022).

Hansen, A. (2019). Environment, Media and Communication. 2nd Edn . London: Routledge.

Harcup, T., and O'Neill, D. (2001). What is news? Galtung and Ruge revisited. J. Stud. 2, 261–280. doi: 10.1080/14616700118449

Horrigan, L., Lawrence, R. S., and Walker, P. (2002). How sustainable agriculture can address the environmental and human health harms of industrial agriculture. Environ. Health Perspect. 110, 445–456. doi: 10.1289/ehp.02110445

Hughes, H. M., (ed.). (1980). News and the Human Interest Story . New York, NY: Routledge.

Iliopoulos, N., and Esteban, M. (2020). Sustainable space exploration and its relevance to the privatization of space ventures. Acta Astronautica 167, 85–92. doi: 10.1016/j.actaastro.2019.09.037

Katz, E. (1957). The two-step flow of communication: An up-to-date report on an hypothesis. Public Opin. Q. 21, 61–78. doi: 10.1086/266687

Katz-Rosene, R. M., and Martin, S. J. (eds.), (2020). Green Meat?: Sustaining Eaters Animals and the Planet . Montreal, QC: McGill-Queen's Press.

Kiang, C. (2020). A Freshly Cooked Meal In Space? It Could Happen Sooner Than You Think. Forbes . Available online at: https://www.forbes.com/sites/charlottekiang/2020/01/16/a-freshly-cooked-meal-in-space-it-could-happen-sooner-than-you-think/?sh=2411e9c56a8e (accessed September 24, 2022).

Klerkx, L., Jakku, E., and Labarthe, P. (2019). A review of social science on digital agriculture, smart farming and agriculture 4.0: new contributions and a future research agenda. NJAS . 90–91, 1–16. doi: 10.1016/j.njas.2019.100315

Kooser, A. (2020). Meat on Mars: Space “BioFarms” Could Serve up “slaughter free” Steaks to Hungry Astronauts. CNET . Available online at: https://www.cnet.com/science/meat-on-mars-aleph-farms-wants-to-serve-slaughter-free-steaks-in-space/ (accessed May 25, 2022).

Krippendorff, K. (2004). Content Analysis: An Introduction to Its Methodology. 2nd Edn. Thousand Oaks, CA: SAGE.

Krujatz, F., Dani, S., Windisch, J., Emmermacher, J., Hahn, F., Mosshammer, M., et al. (2022). Think outside the box: 3D bioprinting concepts for biotechnological applications-recent developments and future perspectives. Biotechnol. Adv. 58, 107930. doi: 10.1016/j.biotechadv.2022.107930

Lamalice, A., Haillot, D., Lamontagne, M.-A., Herrmann, T. M., Gibout, S., Blangy, S., et al. (2018). Building food security in the Canadian Arctic through the development of sustainable community greenhouses and gardening. Écoscience 25, 325–341. doi: 10.1080/11956860.2018.1493260

Launius, R. D., and McCurdy, H. E. (eds.), (2018). Introduction: Partnerships for Innovation. In NASA Spaceflight: A History of Innovation. Cham: Palgrave Macmillan.

Lefers, R. M., Tester, M., and Lauersen, K. J. (2020). Emerging technologies to enable sustainable controlled environment agriculture in the extreme environments of Middle East-North Africa coastal regions. Front. Plant Sci. 11, 801. doi: 10.3389/fpls.2020.00801

Lewis, N. (2019). What's Fueling the Boom in Food Technology? CNN Business . Available online at: https://www.cnn.com/2019/11/04/business/israel-food-technology/index.html (accessed September 24, 2022).

Liang, S. (2021). New Heinz Marz Edition Ketchup has Implications That go far Beyond Flavour. CTV News . Available online at: https://www.ctvnews.ca/lifestyle/new-heinz-marz-edition-ketchup-has-implications-that-go-far-beyond-flavour-1.5657226 (accessed September 24, 2022).

MacCallum, T., Poynter, J., and Bearden, D. (2004). Lessons learned from biosphere 2: When viewed as a ground simulation/analog for long duration human space exploration and settlement. SAE Int. 113, 1095–1104. doi: 10.4271/2004-01-2473

MacLeod, A. (2019). A force for democracy? Representations of the US Government in American Coverage of Venezuela. Front. Commun. 3, 64. doi: 10.3389/fcomm.2018.00064

Martin, N. (2021). Mars Settlement Likely by 2050 Says UNSW Expert – But Not at Levels Predicted by Elon Musk. UNSW Newsroom . Available online at: https://newsroom.unsw.edu.au/news/science-tech/mars-settlement-likely-2050-says-unsw-expert-%E2%80%93-not-levels-predicted-elon-musk (accessed May 25, 2022).

Massa, G. D., Dufour, N. F., Carver, J. A., Hummerick, M. E., Wheeler, R. M., Morrow, R. C., et al. (2017). VEG-01: veggie hardware validation testing on the international space station. Open Agric. 2, 33–41. doi: 10.1515/opag-2017-0003

Mast, J., Coesemans, R., and Temmerman, M. (2017). Hybridity and the news: blending genres and interaction patterns in new forms of journalism. Journalism 18, 3–10. doi: 10.1177/1464884916657520

McCombs, M. E., and Shaw, D. L. (1972). The Agenda-setting function of mass media. Public Opin. Quart. 36, 176–187. doi: 10.1086/267990

McFall-Johnsen, M., and Mosher, D. (2020). Elon Musk Says He Plans to Send 1 Million People to Mars by 2050 by Launching 3 Starship Rockets Every Day and Creating “A Lot of Jobs” on the Red Planet. Business Insider . Available online at: https://www.businessinsider.com/elon-musk-plans-1-million-people-to-mars-by-2050-2020-1 (accessed September 24, 2022).

Meinen, E., Dueck, T., Kempkes, F., and Stanghellini, C. (2018). Growing fresh food on future space missions: environmental conditions and crop management. Sci. Horticult. 235, 270–278. doi: 10.1016/j.scienta.2018.03.002

Mintz, S. W. (2011). Plantations and the rise of a world food economy: some preliminary ideas. Review 34, 3–14. Available online at: http://www.jstor.org/stable/23595132

Mohr, S., and Höhler, J. (2021). Media Coverage of Digitalization in Agriculture—An Analysis of Media Content (SSRN Scholarly Paper No. 3971185). Rochester, NY. Social Science Research Network.

Montenegro de Wit, M. (2022). Can agroecology and CRISPR mix? The politics of complementarity and moving toward technology sovereignty. Agric. Hum. Values 39, 733–755. doi: 10.1007/s10460-021-10284-0

Moritz, J., Tuomisto, H. L., and Ryynänen, T. (2022). The transformative innovation potential of cellular agriculture: Political and policy stakeholders' perceptions of cultured meat in Germany. J. Rural Stud. 89, 54–65. doi: 10.1016/j.jrurstud.2021.11.018

Morris, C. (2018). ‘Taking the politics out of broccoli': debating (de) meatification in UK national and regional newspaper coverage of the Meat Free Mondays campaign. Sociol. Rural. 58, 433–452. doi: 10.1111/soru.12163

NASA (2004). President Bush Offers New Vision For NASA [Feature Articles]. NASA; Brian Dunbar . Available online at: https://www.nasa.gov/missions/solarsystem/bush_vision.html (accessed September 24, 2022).

NASA (2021). Press Release: NASA and Announces Winners of Deep Space Food Challenge. NASA . Available online at: http://www.nasa.gov/press-release/nasa-announces-winners-of-deep-space-food-challenge (accessed September 24, 2022).

Neff, R. A., Chan, I. L., and Smith, K. C. (2009). Yesterday's dinner, tomorrow's weather, today's news? US newspaper coverage of food system contributions to climate change. Public Health Nutr. 12, 1006–1014. doi: 10.1017/S1368980008003480

Newman, L. (2020). “The promise and peril of “cultured meat.”,” in Green Meat?: Sustaining Eaters Animals and the Planet , eds R. M. Katz-Rosene and S. J. Martin (Montreal, QC: McGill-Queen's Press), 169–182.

Newman, L., and Fraser, E. D. G. (2022). Dinner on Mars: The Technologies That Will Feed the Red Planet and Transform Agriculture on Earth. Toronto, ON: ECW Press . Available online at: https://ecwpress.com/products/dinner-on-mars

Obrist, M., Tu, Y., Yao, L., and Velasco, C. (2019). Space food experiences: designing passenger's eating experiences for future space travel scenarios. Front. Comp. Sci. 1, 3. doi: 10.3389/fcomp.2019.00003

Ofori, M., and El-Gayar, O. (2019). “The state and future of smart agriculture: insights from mining social media,” in 2019 IEEE International Conference on Big Data (Big Data) (Los Angeles, CA), 5152–5161.

Ofori, M., and El-Gayar, O. (2021). Drivers and challenges of precision agriculture: a social media perspective. Precision Agric. 22, 1019–1044. doi: 10.1007/s11119-020-09760-0

Pasquinelli, C., and Trunfio, M. (2020). Overtouristified cities: an online news media narrative analysis. J. Sustain. Tour. 28, 1805–1824. doi: 10.1080/09669582.2020.1760871

Patel, R. (2007). Stuffed and Starved: The Hidden Battle for the World Food System . Brooklyn, NY: Melville House Pub.

Patel, R. (2009). Food sovereignty. J. Peasant Stud. 36, 663–706. doi: 10.1080/03066150903143079

Patel, R. (2012). The long green revolution. J. Peasant Stud. 40, 1–63. doi: 10.1080/03066150.2012.719224

Pearce, W., Niederer, S., Özkula, S. M., and Sánchez Querubín, N. (2019). The social media life of climate change: platforms, publics, and future imaginaries. Wiley Interdisciplinary Rev. Clim. Change 10, 569. doi: 10.1002/wcc.569

Pennebaker, J. W., Boyd, R. L., Jordan, K., and Blackburn, K. (2015). The Development and Psychometric Properties of LIWC . Austin, TX: University of Texas at Austin.

Platt, C. A., Jason, M., and Sullivan, C. J. (2020). Public perceptions of private space initiatives: how young adults view the SpaceX plan to colonize mars. Space Policy 51, 101358. doi: 10.1016/j.spacepol.2019.101358

Rainey, K. (2015). Crew Members Sample Leafy Greens Grown on Space Station. NASA . Available online at: http://www.nasa.gov/mission_pages/station/research/news/meals_ready_to_eat (accessed September 24, 2022).

Reinemann, C., Stanyer, J., Scherr, S., and Legnante, G. (2012). Hard and soft news: a review of concepts, operationalizations and key findings. Journalism 13, 221–239. doi: 10.1177/1464884911427803

Resh, H. M. (1989). Hydroponic Food Production: A Definitive Guidebook for the Advanced Home Gardener and the Commercial Hydroponic Grower, 4th Edn. . Santa Barbara, CA. Woodbridge Press Publishing Company.

Rickard, L. N., and Feldpausch-Parker, A. M. (2016). Of sea lice and superfood: a comparison of regional and national news media coverage of aquaculture. Front. Commun. 1, 14. doi: 10.3389/fcomm.2016.00014

Roberts, J. (2007). Education, eco-progressivism and the nature of school reform. Educ. Stud. 41, 212–229. doi: 10.1080/00131940701325688

Rose, D. C., and Bruce, T. J. A. (2018). Finding the right connection: what makes a successful decision support system? Food Energy Secur. 7, 123. doi: 10.1002/fes3.123

Rose, D. C., and Chilvers, J. (2018). Agriculture 4.0: broadening responsible innovation in an era of smart farming. Front. Sustain. Food Syst. 2, 87. doi: 10.3389/fsufs.2018.00087

Rotz, S., Gravely, E., Mosby, I., Duncan, E., Finnis, E., Horgan, M., et al. (2019). Automated pastures and the digital divide: how agricultural technologies are shaping labour and rural communities. J. Rural Stud. 68, 112–122. doi: 10.1016/j.jrurstud.2019.01.023

Ryan, M. (2022). The Social and Ethical Impacts of Artificial Intelligence in Agriculture: Mapping the Agricultural AI Literature. New York, NY: AI and Society . Available online at: https://link.springer.com/article/10.1007/s00146-021-01377-9#citeas

Schmidt, A., Ivanova, A., and Schäfer, M. S. (2013). Media attention for climate change around the world: a comparative analysis of newspaper coverage in 27 countries. Global Environ. Change 23, 1233–1248. doi: 10.1016/j.gloenvcha.2013.07.020

Shiva, V. (1991). The Violence of the Green Revolution: Third World Agriculture, Ecology and Politics . New York, NY: Zed Books.

Smith, M. G., Kelley, M., and Basner, M. (2020). A brief history of spaceflight from 1961 to 2020: An analysis of missions and astronaut demographics. Acta Astronautica 175, 290–299. doi: 10.1016/j.actaastro.2020.06.004

Soma, T., and Nuckchady, B. (2021). Communicating the benefits and risks of digital agriculture technologies: perspectives on the future of digital agricultural education and training. Front. Commun. 6, 762201. doi: 10.3389/fcomm.2021.762201

Space, X. (2022). SpaceX . Available online at: http://www.spacex.com (accessed July 24, 2022).

Sparks, H. (2021). Heinz Makes Ketchup from Tomatoes Grown in Mars Simulator. New York Post . Available online at: https://nypost.com/2021/11/08/heinz-makes-ketchup-from-tomatoes-grown-in-mars-simulator/ (accessed September 24, 2022).

Spring, A., Carter, B., and Blay-Palmer, A. (2018). Climate change, community capitals, and food security: building a more sustainable food system in a northern Canadian boreal community. Can. Food Stud. La Revue Canadienne Des Études Sur l'alimentation 5, 111–141. doi: 10.15353/cfs-rcea.v5i2.199

Steinberg, A. (2011). Space policy responsiveness: the relationship between public opinion and NASA funding. Space Policy 27, 240–246. doi: 10.1016/j.spacepol.2011.07.003

Stephens, J. C., Rand, G. M., and Melnick, L. L. (2009). Wind energy in US media: a comparative state-level analysis of a critical climate change mitigation technology. Environ. Commun. 3, 168–190. doi: 10.1080/17524030902916640

Stollmeyer, M. (2021). Tensions in fostering ‘local food' in the northwest territories: contending with settler colonialism in northern research (Master of Arts, Carleton University). Ottawa, ON.

United Nations (2022). World Population Prospects 2022: Summary of Results . United Nations Department of Economic and Social Affairs, Population Division.

Wamelink, G. W. W., Frissel, J. Y., Krijnen, W. H. J., and Verwoert, M. R. (2021). “Crop growth and viability of seeds on Mars and Moon soil simulants,” in Terraforming Mars. 1st Edn. , eds M. Beech, J. Seckbach, and R. Gordon (Wiley), 313–329.

Wang, M.-T., and Degol, J. L. (2017). Gender gap in science, technology, engineering, and mathematics (STEM): current knowledge, implications for practice, policy, and future directions. Educ. Psychol. Rev. 29, 119–140. doi: 10.1007/s10648-015-9355-x

Weber, B. (2021). Space Bacon, Anyone? Canadian Semifinalists Tackle Space Food Challenge in Contest. Thestar.Com . Available online at: https://www.thestar.com/news/canada/2021/12/12/space-bacon-anyone-canadian-semifinalists-tackle-space-food-challenge-in-contest.html (accessed September 24, 2022).

Wheeler, R. M. (2017). Agriculture for space: people and places paving the way. Open Agric. 2, 14–32. doi: 10.1515/opag-2017-0002

Williams, D. R. (2015). A Crewed Mission to Mars. NASA Goddard Space Flight Center . Available online at: https://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html (accessed September 23, 2022).

Wolfe, P. (2006). Settler colonialism and the elimination of the native. Journal of Genocide Research 8, 387–409. doi: 10.1080/14623520601056240

Wolfert, S., Ge, L., Verdouw, C., and Bogaardt, M.-J. (2017). Big data in smart farming – a review. Agricult. Syst. 153, 69–80. doi: 10.1016/j.agsy.2017.01.023

Yeung, J. (2019). This Company Just Grew Meat in Space for the First Time. CNN . Available online at: https://www.cnn.com/2019/10/08/health/aleph-farms-space-meat-intl-hnk-scli/index.html (accessed May 25, 2022).

Zaller, J. (2003). A new standard of news quality: burglar alarms for the monitorial citizen. Polit. Commun. 20, 109–130. doi: 10.1080/10584600390211136

Zhang, Y., Pribil, M., and Palmgren, M. (2020). A CRISPR way for accelerating improvement of food crops. Nature Food 1, 200–205. doi: 10.1038/s43016-020-0051-8

Keywords: agri-tech, digital agriculture, Mars, space mission, food security, news analysis

Citation: Shaw R and Soma T (2022) To the farm, Mars, and beyond: Technologies for growing food in space, the future of long-duration space missions, and earth implications in English news media coverage. Front. Commun. 7:1007567. doi: 10.3389/fcomm.2022.1007567

Received: 30 July 2022; Accepted: 06 October 2022; Published: 21 October 2022.

Reviewed by:

Copyright © 2022 Shaw and Soma. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Tammara Soma, tammara_soma@sfu.ca

† These authors have contributed equally to this work

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Long-Term Space Nutrition: A Scoping Review

1 College of Landscape and Tourism, Gansu Agricultural University, Lanzhou 730070, China; nc.ude.uasg@hgnat

Hope Hui Rising

2 Department of Landscape Architecture and Urban Planning, Texas A&M University, College Station, TX 77843, USA; ude.umat.hcra@nworbr

Manoranjan Majji

3 Department of Aerospace Engineering, Texas A&M University, College Station, TX 77843, USA; ude.umat@ijjamm

Robert D. Brown

This scoping review aimed to identify current evidence and gaps in the field of long-term space nutrition. Specifically, the review targeted critical nutritional needs during long-term manned missions in outer space in addition to the essential components of a sustainable space nutrition system for meeting these needs. The search phrase “space food and the survival of astronauts in long-term missions” was used to collect the initial 5432 articles from seven Chinese and seven English databases. From these articles, two independent reviewers screened titles and abstracts to identify 218 articles for full-text reviews based on three themes and 18 keyword combinations as eligibility criteria. The results suggest that it is possible to address short-term adverse environmental factors and nutritional deficiencies by adopting effective dietary measures, selecting the right types of foods and supplements, and engaging in specific sustainable food production and eating practices. However, to support self-sufficiency during long-term space exploration, the most optimal and sustainable space nutrition systems are likely to be supported primarily by fresh food production, natural unprocessed foods as diets, nutrient recycling of food scraps and cultivation systems, and the establishment of closed-loop biospheres or landscape-based space habitats as long-term life support systems.

1. Introduction

From time immemorial, fresh and packaged food onboard long-term transportation systems has been a topic of intense research [ 1 , 2 ]. In addition to facilitating Earth exploration, and most famously, the discovery of the new world, nutrition became a commercial entity and ushered in a new age in human exploration [ 3 , 4 , 5 , 6 ]. The Industrial Revolution and the ensuing progress of humanity can be largely attributed to the nutrition industry, which provided capacitance against natural disasters and calamities, while ensuring food security for the burgeoning world population. Space exploration in the mid-20th century has also greatly benefited from the advancing trends in the food industry. Looking into the future, a variety of new techniques and technologies continue to be researched to harness resources from the harsh space environment to provide a sustainable means of space nutrition, while influencing the food preservation and culinary practices of future generations [ 7 , 8 ].

1.1. Backgrounds

Humans have been involved in manned spaceflight for the past five decades, with the International Space Station (ISS) as the main destination for short-term missions. Major space agencies’ extensive plans for a long-term human presence in space have also motivated missions to the Moon and Mars [ 9 , 10 , 11 ]. Extensive research activities are being carried out by various researchers to support long-term human presence in space. One notable example is the 8-month isolation mission called the Hawaii Space Exploration Analog and Simulation (HI-SEAS) III expedition. This recent research work by the National Aeronautics and Space Administration (NASA) involves space exploration simulation and modeling in the HI-SEAS habitat, a dome of 135.8 square meters with food and life support systems designed to simulate the conditions on Mars. To investigate the best way for astronauts to maintain optimal nutritional intake during long-term life on Mars or the Moon, researchers at the HI-SEAS facility explore new forms of foods and food allocation strategies for deep-space manned missions so that functional foods can be formulated and processed for consumption by astronauts in outer space [ 12 ].

For manned short-duration missions, astronauts rely on nutritional supplies carried from the Earth and sustained by specialized delivery missions. These food products have a shorter shelf life than the duration of long-term space missions to Mars. Moreover, the techniques used for processing these food products makes them limited in terms of satisfying consumers’ nutritional requirements. Due to the tradeoffs between taste, nutrition, storage, and packaging considerations, the limited palatability of processed space foods can lead to menu fatigue, preventing astronauts from taking in enough food to acquire sufficient nutrients. On the other hand, processed space foods cannot provide the full range of diverse nutrients necessary to help astronauts effectively combat bone loss [ 13 , 14 , 15 ], muscle atrophy [ 15 , 16 ], cardiovascular dysfunction, upright intolerance, and other physiological challenges associated with the extreme environment in space [ 17 , 18 , 19 ]. While exercise and medical support are both necessary to overcome some of these challenges, special nutritional resources are vital for in-flight adaptation and post-flight recovery.

To compensate for the aforementioned deficiencies in the existing space nutrition system, which largely relies on processed food, fresh food materials are necessary. In fact, various digestive problems have been identified and are thought to be associated with the lack of fresh fruits and vegetables and fiber-rich meals, even with the use of supplements to increase the diversity of nutrients in space nutrition [ 12 ]. However, the recent space dietary research from EuroMoonMars IMA HI-SEAS II (EMMIHS-II) mission significantly limited food choices to freeze-dried foods and prohibited the use of fresh foods because fresh foods were considered too microbiologically fragile to meet the sanitary needs of the missions [ 12 ]. While freeze-dried foods make no contribution to psychological wellbeing, fresh foods provide a sense of familiarity to help sustain the mental health of astronauts and future space tourists [ 12 ]. As relying solely on packaged foods may not be feasible for long-term space exploration, advanced lighting, irrigation, and greenhouse systems have been developed to optimize plant growth in outer space to make fresh space foods possible [ 12 ]. Deep space exploration resupply programs will require self-sufficient closed-loop ecosystems of resource production and regeneration to provide renewable resources that minimize energy consumption [ 20 , 21 , 22 ] and maximize the use of higher plants and other autotrophs [ 23 , 24 , 25 , 26 , 27 , 28 , 29 ].

1.2. Rationale and Objectives

The most recent approach in space nutrition research has focused on adapting dietary plans to each astronaut while proposing alternatives to address food intolerances and aversions among a small group of astronauts [ 12 ]. However, this approach does not produce a generalizable evidence-based dietary plan for a much larger group of humans than the six astronauts that participated in the study. There is a growing demand to advance space nutrition systems in response to the emerging commercial space needs. The advent of companies such as SpaceX, Blue Origins, and Virgin Galactic has opened space for recreational opportunities for humans [ 1 ]. Optimizing long-term space nutrition for the likely multi-cultural space tourists and inhabitants of the near future is essential to the success of commercial space activities and space tourism.

This scoping review serves as a first step towards developing evidence-based space menus and production systems for long-term exploration and occupation of other planets. The review aimed to use a multi-national perspective to scope the extent to which space nutrition meets the diverse dietary needs for the short-term and long-term adaptation of human psychophysiology in the adverse space environment. The objective of the scoping review is to identify knowledge gaps and to synthesize evidence around nutrient deficiencies and dietary strategies to inform hypotheses to be tested in future experiments with a larger sample of more diverse participants that have a wider range of psychophysiological baselines.

2. Materials and Methods

This scoping review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist. Some of the checklist items were not used because they were designed for meta-analyses, which are out of the scope of this review. As a result, relevant checklist (CL) items were reported in the article with item numbers instead of a stand-alone checklist form with page numbers. The article was identified as a scoping review in the title for checklist item 1 (CL-1). The abstract provided the structured summary required for CL-2. Section 1.2 provides the rational and objectives for CL-3 and CL-4.

2.1. Protocol and Registration Information Sources

CL-4 requires the review protocol and registration to be included under methods. As the international prospective register of systematic reviews (PROSPERO) does not accept the registration of scoping reviews, a registration number for this scoping review is not available. Figure 1 illustrates the PRISMA review protocol used by two independent reviewers between November 2019 and December 2021.

Review protocol for searches of databases, registers, and other sources.

2.2. Search Strategies and Eligibility Criteria

The preliminary search for the initial pool of review and non-review articles was conducted using “space food and the survival of astronauts in long-term missions” as the search phrase. The review articles from the selection were used to identify emerging themes and recurrent keywords as eligibility criteria required by CL-6. The first round of title and abstract screening was conducted using the following three themes as eligibility criteria: (1) acquiring fresh food materials in the long-term space mission, (2) maintaining a self-sufficient space survival mode, and (3) establishing human habitats. The theme-relevant articles were further filtered using the list of keywords in Table 1 to identify the final collection of articles for full-text reviews.

Relevant references for the final list of keywords as eligibility criteria.

2.3. Information Sources

For CL-7 on information sources, the preliminary search identified review and non-review articles from 14 databases ( Table 2 ). The dates of coverage span from 1964 to 2021. The most recent search was executed on September 5, 2021.

List of databases used for the systematic review.

* Accessed date: 5 November 2019.

2.4. Search and Selection of Sources of Evidence

In total, 5432 results were obtained from the preliminary search. After removing duplicates, 4320 papers were left for the first round of title and abstract screening using the three themes to select 535 papers for another round of title and abstract screening. The list of keywords from Table 2 were then used as inclusion criteria to identify 218 articles for full-text screening. Figure 1 shows the screening process and results as a flowchart using the PRISMA template.

3.1. Current State of Space Nutrition

3.1.1. key components of space nutrition.

Nutrition has many important functions in space travel, from providing enough nutrients and meeting the metabolic needs of a healthy body to enhancing an individual’s emotional well-being. Nutrition also plays a key role in offsetting many negative effects of space travel, such as radiation exposure, immune deficiency, oxidative stress, and bone and muscle loss [ 30 ]. Therefore, space nutrition must provide reasonable support for optimal physiological and psychological wellbeing in space in addition to accommodating diverse tastes, variety, and acceptability. Space nutrition should meet the daily human needs for protein, fat, and sugar, as well as inorganic elements, trace elements, fat-soluble vitamins, and various water-soluble vitamins. Space nutrition contains 16 essential nutrients: protein, calcium, iron, vitamin A, vitamin C, thiamine, riboflavin, vitamin b-12, folate, vitamin D, vitamin E, magnesium, potassium, zinc, fiber, and pantothenic acid [ 31 ]. In-flight nutrition requirements are set by the World Health Organization (WHO) according to the daily requirements of people on Earth. Therefore, a macronutrient composition with an average of 15% protein, 30% lipids, and 55% carbohydrates is recommended as a bare minimum [ 31 , 32 ].

3.1.2. The Evolution of Space Nutrition

The evolution of space nutrition has been well documented by nutritional literature and NASA [ 33 , 34 , 35 , 36 ]. In the early 1960s, the research on space food systems focused largely on calorie-dense, nutritious, and palatable food without provisions for specific food storage on the spacecraft for short-duration missions. American and Russian astronauts lost weight from consuming primarily aluminum tubes packed with minced meat, jam, and other paste food, as well as bite-sized cubes with high-calorie mixtures of protein, fat, sugar, fruit, or nuts. Although these space foods met the nutritional, sensory, and microbiologic prerequisites in ground-based tests, astronauts experienced menu fatigue [ 35 ]. While dehydrated food and ice were developed in collaboration with the U.S. army’s Natick laboratory, rehydrating foods was difficult until hot water became available for the Apollo program (1968 to 1972) to improve the taste of space food [ 35 ].

The missions became longer from the mid-1960s to the early 1970s. Consequently, increased variety, improved quality, and longer-term storage shifted the focus of space nutrition towards packaged foods such as cans, food bars, and retort pouches [ 35 ]. Retorting enabled food storage at ambient temperature for a long period by thermally sterilizing the food [ 35 ]. Eating from open containers with utensils became possible for the first time as rehydrated foods were made more prominent in the space food systems by the abundance of by-product water from the increasing use of hydrogen and oxygen fuel cells to power American spacecraft [ 34 ]. The character and flavor of rehydrated food are closer to those in the common diet on the ground. While satisfying the taste of astronauts and increasing food choices [ 37 ], dehydration also helped reduce storage space and power needs by minimizing the need for food refrigeration [ 34 , 35 ].

The rapid development of food refrigeration and heating equipment on manned spacecraft facilitated the use of thermal stabilization bags, canned fruit, irradiated meat, and freeze-dried food in subsequent stages of space flight. Today, the types and varieties of space food are quite close to the nutritional choices available terrestrially. Astronauts aboard the ISS are able to eat fresh vegetables, fruits, and heated soup for most meals. The food supply during space flight must be safe, nutritious, convenient, and compact, while meeting the psychological and taste requirements of astronauts under weightlessness or artificial gravity.

3.1.3. Space Food Categories

The main space food categories are canned food, dehydrated food, medium moisture food, natural food, refrigerated food, fresh food, irradiated food, and functional food [ 30 ]. The first five types of space food are relatively mature and widely used, while the last three kinds of space food are popular foods being actively developed to meet the emerging needs of commercial and recreational space flights and long-term space missions. The ISS recently started to test the viability of an on-demand nutrient production system composed of a desiccated yeast strain and edible growth substrate to produce ready-to-consume nutrients for long-duration missions [ 38 ]. While on-demand nutrient production system may become a new space food category once it has been validated to be safe and feasible, it is the least familiar type of food for astronauts. Despite its short shelf life, fresh food has been and will still be necessary for improving space food acceptability. The ISS provides astronauts with fresh food, mainly fruits and vegetables for direct consumption or vegetable salads [ 41 , 42 ]. Irradiated food refers to food sterilized by irradiation. Although this method processes food in small quantities most of the time, irradiation-based sterilization can be mass produced, especially by exploiting the harsh radiative atmosphere in outer space. Currently, irradiated food on the ISS mainly includes meat and bread. Korean scholars developed ready-to-eat consumables such as nutrition bars, noodles, and two kinds of traditional Korean food (kimchi and cinnamon beverage) by using high-dose gamma-ray radiation treatment [ 41 , 42 ]. Functional food alludes to special nutrients with supplemental health functions as space food additives to help astronauts better cope with the adverse effects of space living conditions through absorbing the restorative effects of the supplementation in a long-term manner. Anti-radiation functional food is an example of such approach [ 42 , 43 ].

3.1.4. Space Food Menus

After decades of effort, space food has enjoyed a diversification of variety and taste. To avoid monotony, the diets for the American and Russian astronauts are generally based on a 4-to-6-day cycle, during which the food is different every day except for the drinks. Much of the Russian space food is canned. Lamb with vegetables, beef with barley, sturgeon, and chicken rice are the meal options that typically appear on the Russian menu. These options can be heated in the microwave. There are also many dehydrated foods, such as tvorog, macaroni, tomatoes, fried rice, and shrimp. The general diet of the American astronauts is divided into A, B, and C meals: an A meal has peaches, roast beef, scrambled eggs, pancakes, cocoa, orange drinks, vitamin pills, and coffee; the B meal consists of pork mix, turkey sausage, bread, bananas, almond crackers, and apple drink; the C meal is composed of shrimp, steak, risotto, broccoli, cocktail, pudding, grape juice, and ice cream. Chinese aerospace recipes are mainly made of traditional Chinese dishes, such as eight treasure rice, tangerine beef, beef in soy sauce, lotus seed porridge, green tea, ink fish balls, beef balls, and other Asian delicacies.

3.2. Limitations of Existing Space Nutrition

The following limitations have been the major drivers for innovations that contribute to the advancement in space nutrition.

3.2.1. Dominance of Processed over Fresh Food

At present, astronauts are provided mainly with processed and packaged food. Fresh vegetables and fruits can only be enjoyed in the early stage of a space mission due to limited storage time and high cost. It is estimated that a 3-year Mars mission with a crew of six would have a total energy expenditure of 12 megajoules per person per day, regardless of water requirements, and would carry 22 tons of water-containing food on the spacecraft [ 44 ]. Even if the water is completely recycled and the food is partially dehydrated, the transport costs are estimated to be very high (20,000 euros per kilogram) [ 40 , 45 ]. The ISS prioritizes processed food with minimal weight and high nutrient density due to the significant cost associated with transporting fresh food.

Astronauts’ interest in health-promoting food, including fresh vegetables, is on the rise. There is no substitute for a healthy diet related to vegetable intake because fresh vegetables contain many health-promoting properties, including vitamins, minerals, dietary fiber, and secondary compounds [ 77 ]. The lack of adequate fresh vegetables and fruits is one of the most significant current challenges of space nutrition.

3.2.2. No Quality Advantage for Resource-Intensive Refrigerated and Frozen Food

Fuel cells provide water to astronauts as a by-product from energy generation. The ISS recently started using solar cells to harvest energy from the sun. However, water and electricity remain extremely valuable and scarce resources due to the weight constraint of a space shuttle. These water, power, and weight limitations continue to make it challenging for space missions to accommodate freezers and refrigerators. Until these limitations have been addressed, there is no quality advantage to using refrigerated and frozen food [ 31 ].

3.2.3. Space Food Supply Is Restricted by Limited Transportation and Storage Space

Mission resources, including power, size, mass, crew time, and waste disposal capacity, must be considered when developing space nutrition systems. Misuse of these resources will affect the success of the mission. While food and resource use may be contradictory, both are critical to the success of the mission [ 31 ]. Due to the high resupply cost, it is unrealistic to rely on transporting materials from the Earth to support long-term space missions and human settlements on other planets. There is a need to develop regenerative and self-sufficient water, food, and energy production systems.

3.2.4. Long-Term Space Nutrition Requirements for Food Storage and Cooking Methods

A long-term space nutrition system must maintain sensory palatability, nutritional efficacy, and safety over a period of 3 to 5 years. NASA has aimed to develop nutrient-dense and environmentally sustainable food compatible with the cooking processes for microgravity [ 31 ]. However, it is challenging to use these same cooking processes to make space food last for more than 3 to 5 years without changing the food quality and nutritional value at the expense of human health. Even with the development of artificial gravity, which will make more food preparation and preservation methods feasible, the adoption of Earth-based systems for long-term space nutrition requires a drastic reduction in the external input of resources and output of wastes.

3.2.5. Diet Menu Fatigue

Food acceptability can be affected by eating habits. Food and mealtimes can help promote solidarity among astronauts, resulting in important psychological and social benefits [ 31 ]. Food and mealtimes play a key role in reducing the stress and boredom from prolonged task execution, while delicious food provides pleasure for the eater. The appearance, taste, texture, and smell of food can have a significant psychological impact on astronauts [ 48 ]. Despite the great variety of food available today, it is still not enough for long-term space missions that last several years. However, the importance of the space food supply to long-term space missions cannot be understated. During the simulated manned landing on Mars experiment of MARS500 in Russia, many subjects showed “diet menu fatigue” and even became tired of their favorite food [ 49 ].

3.2.6. Lack of Nutrients to Cope with Extreme Conditions of Space

In addition to being nutritious and safe, space food needs to function as a countermeasure to the negative effects of spaceflight by including nutrients that help the human body and mind adapt to weightlessness and the extreme conditions of space [ 49 , 50 , 51 ]. While the lack of gravity and circadian rhythm are well-known and widely studied aspects of spaceflight travel, there is a need for a more comprehensive nutritional study on other ancillary conditions, such as food taste alteration (due to the changes in atmospheric pressure) and the adaptations of human digestive, olfactory, and perception systems to long-term space habitation.

3.3. The Influence of Adverse Space Environment on Astronauts’ Diet and Health

The space environment is quite different from the terrestrial environment on Earth. Astronauts are faced with several unfavorable conditions for human survival: microgravity, radiation, confined space, motion sickness, and circadian rhythm changes, as well as a low-pressure atmosphere that is low in oxygen and high in carbon dioxide. Human spaceflight data show that space environments characterized by microgravity and 90 min light/dark cycles trigger countless adaptive responses from almost all physiological systems. These adaptive responses can lead to a loss of body mass, fluid transfer, electrolyte imbalance, dehydration, constipation, loss of potassium, loss of calcium, loss of red blood cell mass, intestinal microecological disorder, and space motion sickness [ 188 ]. The diet and health of astronauts can be negatively impacted by the adverse living conditions during manned flight [ 52 ].

3.3.1. Less Energy Intake and Weight Loss

Preliminary results from terrestrial studies have shown that an increased protein/carbohydrate ratio is correlated with long-term weight maintenance after weight loss [ 78 ]. Such weight maintenance strategies have yet to be tested against the averse living conditions in space. It is challenging for astronauts to maintain their energy balance during long space flights [ 79 , 80 ]. This negative energy balance leads to weight loss [ 79 , 80 , 95 , 96 , 97 ]. Astronauts typically lost 2% to 5% of their pre-flight weight [ 53 , 99 , 100 , 101 , 102 ]. In many cases, more than 10% weight loss was observed even though there was plenty of food on board [ 45 ]. If sustained, this could result in a weight loss of 5 kg per month [ 45 ]. A mission to Mars could result in an initial weight loss of 15% or more, which could have serious health implications [ 45 ].

On Earth, a long-term negative energy balance can lead to compromised muscle performance, impaired cardiovascular function, increased muscle fatigue, increased susceptibility to infection, impaired wound healing, altered sleep, and decreased overall well-being [ 102 ]. Chronic energy deficiency can exacerbate some harmful physiological adaptations to the space environment, resulting in cardiovascular dysfunction, bone density, muscle mass and strength loss, impaired exercise ability, and immunodeficiency [ 45 , 54 , 55 , 102 ]. These physiological changes may jeopardize the health and performance of the crew, as well as the overall success of the mission [ 52 ].

Astronauts need to consume more food to offset the decrease in their energy intake due to microgravity, small spaces, insufficient exercise, and shortened circadian rhythm changes. However, the poor palatability of processed and packaged space food causes the astronauts to eat less. Astronauts, on average, eat 25–30% less than they did before flying [ 30 ]. Studies have shown that microgravity conditions do not change the amount of metabolic energy (i.e., nutrients that enter the blood through intestinal cells for use by cells) required to stay healthy [ 99 ]. Although body water loss occurs during space flight, this can only explain part of the decline in body mass [ 101 ]. The decrease of energy intake is the main cause of negative energy balance. A comprehensive review of anorexia in spaceflight suggests that microgravity during spaceflight leads to increases in the two hormones (Leptin [ 85 ] and GLP-1 [ 56 , 86 ]) that cause satiety. These changes in appetite-related hormones may cause the decrease in appetite observed during spaceflight. Other biological factors also affect appetite, such as astronauts’ preference for carbohydrates rather than fats [ 81 , 82 ].

During spaceflight, reduced food intake [ 81 , 82 , 83 ] and impaired anabolic responses [ 215 ] may reduce the production of reactive oxygen species (ROS) in mitochondria [ 57 ], and this further leads to aging, disease, and cell death [ 57 , 58 ]. Chronic under-intake causes permanent damage to the body [ 58 ].

While exercising in space is a popular idea for reducing muscle and bone loss and cardiovascular cleansing, it increases total energy expenditure, necessitating a greater energy intake to maintain energy balance. Exercise may further affect eating behavior, leading to acute anorexia, which can exacerbate anorexia [ 30 ]. Fresh, tasty food may stimulate the astronauts’ appetite to make them eat more. Nutrient-dense food can also help to increase energy intake more efficiently through eating.

3.3.2. Effect of Microgravity

In the presence of microgravity, the energy cost of daily activities is greatly reduced due to the waste of muscles and the reduction of exercise cost in microgravity [ 45 ]. Responses to microgravity include fluid redistribution, reduced plasma volume, rapid loss of muscle mass and strength, cardiovascular deconditioning, impaired aerobic exercise capacity, bone-loss, immune and metabolic alterations, as well as effects on the central nervous system [ 87 , 88 ]. Muscle and bone atrophy and loss of cardiovascular function, which characterize the aging process, occur 10 times faster in space than on Earth due to microgravity-induced physiological changes [ 89 ].

3.3.3. Long-Term Radiation

Space radiation can cause harmful effects such as DNA damage [ 90 , 91 ] and cell aging [ 92 ]. The higher cardiovascular risk among Apollo astronauts is presumed to be associated with exposure to severe deep space radiation [ 93 ]. Oxidative stress induced by space radiation and microgravity is an important factor leading to aging and disease [ 94 ]. The main measure for astronauts to resist deep space radiation is to rely on space protection facilities. Functional foods rich in anthocyanin and Omega-3 fatty acids have been used to slow down the damage caused by radiation.

3.3.4. Metabolic Stress

Space missions cause metabolic stress among astronauts. Metabolic stress affects major body systems, increases the metabolic rate, and suppresses the immune system. Metabolic stress is also a strong predictor of type 2 diabetes and cardiovascular disease [ 93 ]. In addition, associated oxidative stress and inflammation have recently been implicated in the process of muscle atrophy [ 94 ] and bone loss [ 104 ]. Spaceflight has a short-term impact on the body’s iron metabolism and can lead to iron deficiency anemia as a long-term effect [ 61 ].

3.3.5. Changes in Physical Condition

Astronauts often stay in bed because of their limited mobility and reduced exercise. As a result, astronauts are similar to the general population of sedentary, inactive adults and people who are confined to bed [ 62 ]. At rest, the astronauts’ core temperature will be 1 °C higher than on Earth [ 63 ]. This can be attributed to an impaired convective heat transfer and evaporation process to cool down the body, low-grade pro-inflammatory responses to weightlessness, psychological stress-induced hyperthermia, and strenuous exercise protocols leading to the so-called “space fever” [ 63 , 64 , 65 ].

3.3.6. Intestinal Microecology Disorder

Microgravity leads to decreased beneficial and increased harmful bacteria in the intestinal flora. The gastrointestinal function changes accordingly, affecting the digestion and absorption function of the human intestinal tract over time [ 66 ]. In the spacecraft’s sealed living environment, relatively common infections (such as epidemic cerebrospinal meningitis, penicillin resistance staphylococcus genus) may also endanger the life of astronauts and threaten the mission [ 67 , 188 ].

3.3.7. Vision Damage

Astronauts’ eyesight changes after landing [ 103 ]. More than half of American astronauts have a refractive change in their eyes after a long spaceflight. Findings have also included structural changes in the eye and signs of increased intracranial pressure [ 68 ].

3.3.8. Fluid and Electrolyte Imbalance

Changes in liquid and electrolyte balance due to short-term exposure to microgravity have been observed in the past [ 216 ]. Such long-term and sustained changes may adversely affect the health of the crew and thereby jeopardize the success of the mission.

4. Discussion

Improper nutrition refers to insufficient or excessive nutrition. Lack of nutrition will lead to the risk of not being able to live and work healthily. In addition to the traditional deficiencies of protein, vitamins E, K, D, polyphenols, and polyunsaturated fatty acids, deficiencies of minerals (calcium and potassium) and low elements (iron) have been observed in long-term space missions. [ 53 ]. Excessive intake of certain nutrients may lead to symptoms such as scurvy and beriberi [ 69 ]. Improper nutrition is not associated with caloric intake. During the European mission at the end of the last century [ 217 , 218 ], astronauts had an inadequate intake of energy, liquid, and calcium in addition to excessive sodium compared to the dietary reference intake on Earth. Inappropriate levels of these nutrients have considerable effects on hormonal regulation, cardiovascular functioning, and calcium and bone metabolism. Efficient space nutrition should function as a countermeasure for the effects of the space environment on astronauts’ physiology and metabolism [ 30 , 84 ]. Therefore, space nutrition should not only provide astronauts with sufficient energy intake but also allocate nutrients to counteract the adverse effects of the space environment [ 83 ]. This section outlines possible future research directions for space nutrition as countermeasures for the effects of adverse space living conditions.

4.1. Nutritional Measures to Cope with Reduced Intake

This section outlines possible future research directions for space nutrition as countermeasures for the effects of adverse space living conditions.

4.1.1. Increase Palatability through Fresh Food with Distinctive Flavors

The reduced intake of space food by the astronauts is potentially because their sensory responses to the taste, smell, and texture of food in space [ 50 ] reduce the perceived attractiveness of food [ 45 , 99 , 100 ]. Even though the quality of food has improved since the beginning of the space program, food provided to astronauts is still not as palatable as what is available on Earth. At the same time, the artificial fortification of food can lead to the destruction of nutrients over a long period of time and can also produce an unpleasant taste [ 31 ]. Processed food has major limitations. The 3-to-5-year shelf life limits the variety of processed food, and many processed food items lose their original flavor. The traditional focus on the form of food and meeting the crew’s caloric needs is no longer sufficient for long-term missions [ 31 ]. There is an urgent need for fresh food with distinctive, original flavors. Future research should investigate ways to maximize fresh food production despite the space, weight, and resource constraints during space flight.

4.1.2. Boost Energy Intake through Dietary Culture and Food Production Activities

The stress astronauts experience during spaceflight alters their appetite and energy intake [ 217 , 218 ]. Improvements in the variety and quality of food and the emphasis on dietary culture may help boost their energy intake [ 45 ]. Dietary culture involves the use of familiar food sources and utensils, cooking methods, and eating methods and places. Meals play an important role in people’s emotional and social wellbeing. Having astronauts participate in the production, harvesting, and cooking of ingredients not only increases the amount of exercise for them but also relieves stress and induces happiness. The happiness induced can be mainly attributed to the sense of fulfillment one obtains from participating in the agricultural process. Further, cooking and sharing food together helps astronauts identify with the space environment and feel a sense of belonging. The resultant place identity and attachment increase the astronauts’ food intake, helping to maintain their physical health. In space exploration missions, the creation of human habitats around food production areas as loci of emotional attachment and social interactions is paramount to the success of long-term missions.

4.1.3. Enhance Caloric Intake through Nutrient-Dense and Fresh Foods

The type of food and the amount of nutrients in the diet can also affect caloric intake [ 45 ]. Astronauts often prefer carbohydrates rich in energy and micronutrients [ 81 , 118 ]. However, the supply of such low-density food is limited, because the space environment presents unique challenges for transporting large quantities of food. If carbohydrates are used in large quantities to provide space nutrition, large quantities of drinks and vegetables will also be required [ 31 ].

Nuts are by far the most effective food, with relatively high energy and important nutrients in a compact food matrix. However, nuts are rich in fat and protein, both of which can affect shelf life. Future space nutrition research should address significant gaps in supplying more lightweight nutrient-dense foods [ 31 ] and developing fresh food production methods to better meet the astronauts’ demand for a large amount of carbohydrates, vegetables, and drinks.

4.1.4. Counterbalance the Effects of Space Environment on Leptin Secretion with Nutrition

The high concentration of carbon dioxide in spacecrafts and the ISS changes energy intake and reduces food consumption [ 70 , 71 ]. Astronauts’ eating habits are affected by the 90-min diurnal cycle in the Earth’s orbit and the insufficient light level in spacecraft [ 51 , 72 ]. The ambient light cycle variations disrupt the circadian rhythms and affect the hormonal balance in the body [ 73 , 74 , 75 ]. For example, changes in light and dark cycles have been shown to change the rhythmicity of leptin secretion and affect food intake and body weight in rodents [ 76 ]. Thus, continuous light exposure may at least partially explain the higher leptin levels in astronauts [ 56 , 72 ]. To mitigate the effects of excess leptin, space nutrition research should investigate ways to reduce inflammatory foods, such as sugary drinks and trans fats while increasing anti-inflammatory foods, such as olive oil, avocado, coconut, fish, and grass-fed pasture-raised animals. Long-term space habitats should be designed to regulate circadian rhythms and facilitate the production of anti-inflammatory foods. To overcome the payload limitations at launch while providing non-plant-based proteins, future research should investigate ways to use in-space manufacturing to construct large-scale space habitats with artificial gravity to accommodate growing at least fish, if not animals, from embryos.

4.1.5. Improve Immunity with Nutritional Measures

Astronauts had different immune responses to a decrease in their energy and nutritional intake [ 69 ]. For example, a decrease in mitogen proliferation reaction is related to deficiency in Vitamin B6 (VB6), Vitamin B-12 (VB12), biotin, Vitamin E (VE), copper or selenium. Delayed hypersensitivity is associated with VB6, VB12, VC, or iron deficiency. Protein and individual amino acid deficiencies have different effects on various immune functions [ 84 , 119 ]. Providing effective nutrition for astronauts can help to combat immune dysfunction during spaceflight.

4.2. Nutritional Countermeasures for the Effects of Microgravity

There are a wide range of health risks associated with the side effects of adapting to weightlessness during space flight. These side-effects include changes in musculoskeletal, cardiovascular, neural vestibular, immune, endocrine, and other physiological systems. Muscle catabolism and bone loss are two physiological changes that occur in weightlessness. The use of exercise and medication has limited success in mitigating these side effects without an appropriate diet to mitigate the deleterious effect of microgravity [ 83 , 120 ]. A recent study shows for the first time that adequate energy, protein, and vitamin D supplies are needed to maintain bone density after a 6-month spaceflight [ 103 ].

4.2.1. Mitigate Bone Loss with Nutritional Measures

Bone loss is one of the important factors affecting astronauts’ health. Although its mechanism is not fully understood, it is clearly multifaceted. Dietary intake resists changes in bone metabolism during space flight. An optimized diet [ 105 , 106 ] helps to mitigate bone loss with little risk of side effects by providing adequate amounts of calcium, vitamin D, and vitamin K in the space diet [ 107 ]. Many parallels have been found between nutritional orthopedics and space nutrition because of the similar challenges faced by an aging orthopedic patient on Earth and an astronaut experiencing the degenerative effects of long-duration space missions [ 108 ]. A daily balance of fiber, liquids, and bioactive substances, such as coffee, is necessary to prevent hip fracture when transitioning from a low-gravity field to hyper-gravity while landing on a planet.

4.2.2. Reduce Sodium Intake

Most space food has a high sodium content, mainly sodium chloride. This leads to a high dietary sodium intake for astronauts, averaging more than 5000 mg/day and more than 12,000 mg/day for individuals [ 53 , 55 , 82 , 132 , 133 ]. High sodium chloride intake increases urinary calcium excretion [ 134 , 135 , 219 , 220 ] and the risk of kidney stones [ 136 ], as well as low-grade metabolic acidosis [ 137 , 138 ], which further leads to increased bone resorption [ 138 ]. A reduced intake of sulfur-containing amino acids and sodium chloride has been shown to reduce bone loss during bed rest [ 109 ]. NASA has made an enormous effort to reformulate 90 foods to reduce sodium intake to 3000 mg/day [ 109 ]. As sodium chloride is a food additive used in space food processing and preservation, it is challenging to reduce sodium content without negatively affecting the taste of food. The ultimate solution to excess sodium intake is to replace packaged food with fresh food.

4.2.3. Increase Intake of Vegetable Protein, Potassium, and Bisphosphonates

The ratio of protein to potassium in the diet may also affect bone metabolism [ 109 , 110 ]. The type of protein in the diet is also important for bone health [ 103 ]: animals have lower potassium (and potassium salts) than plants. Animal proteins are usually high in sulfur-containing amino acids, and animals have lower potassium than plants. The oxidation of sulfur-containing amino acids may lead to low-level metabolic acidosis and corresponding bone resorption which can be compensated by reducing the animal protein–potassium ratio, especially in the final stages of bed rest studies [ 103 ]. The arrhythmias in the Apollo 15 astronauts were caused by a lack of potassium due to a lack of nutrients in the space food system [ 110 ]. The potassium deficiency in this short-term task was alleviated by potassium supplementation in the subsequent task [ 31 ]. Potassium citrate, as a non-sports antagonism scheme for renal calculi, has been transferred from the flying observation stage to the clinical research stage. In addition to vegetables that are rich in plant protein and potassium, supplementation with bisphosphonates may be a countermeasure to bone loss [ 122 , 123 ]: potassium-rich foods include legumes, peanut, mushroom, laver, and kelp. Plant protein mainly comes from various forms of beans.

4.2.4. Increase Vitamin D Intake

Adequate energy and vitamin D intake, as well as regular resistance exercise, can significantly improve bone condition [ 103 ]. A space nutrition system low in vitamin D, coupled by the lack of ultraviolet radiation, leads to vitamin D deficiency in the astronauts [ 47 ]. Inadequate intake of vitamin D supplements can cause body reserves to lose vitamin D during flight [ 53 , 111 ]. While vitamin D may not be the cause of bone loss during space flight, it certainly exacerbates the problem. Foods that contain more vitamin D include fish, milk, liver, eggs, mushrooms, and beef. It is imperative for long-duration space flights to develop effective means to cultivate mushrooms because it is not feasible to produce fresh fish and animal protein in the near future due to weight and space limitations associated with the current space flight capabilities.

4.2.5. Increase Vitamin K Intake

Newborns, pregnant women, and astronauts tend to experience deficiencies in vitamin K, which is known as the clotting vitamin. There are two kinds of natural vitamin K: (1) vitamin K1 promotes blood clotting for female astronauts to help reduce period hemorrhage in great quantities and prevent internal hemorrhage and hemorrhoid [ 124 ]; (2) vitamin K2 is involved in bone metabolism. Studies have found that loss of vitamin K is associated with low bone mass or increased bone loss [ 125 ]. Supplementation with vitamin K has been shown to normalize low carboxylate levels of osteocalcin, counterbalancing the loss of bone formation [ 126 , 127 ] and helping to protect astronauts from bone loss. At the same time, vitamin K can promote the absorption of calcium elements to effectively prevent bone marrow calcium loss.

Vitamin K-rich foods include yogurt, alfalfa, egg yolks, fish eggs, algae, carrots, and green leafy vegetables. The roots of Gynura bicolor ( Begonia fimbristipula in Latin) have been used as a functional food in aviation because they contain vitamin K, which is absent in most vegetables. It has been developed as a functional food in aviation [ 128 ]: after the human body absorbs the vitamin K1 in Gynura bicolor, the vitamin K1 will be partially converted into the vitamin K2. This plant has a significant application value in addressing calcium and bone loss for the astronauts because it can effectively improve their physiological function through promoting the rapid normal coagulation of blood and increasing the absorption of calcium to minimize bone loss. In addition, Gynura bicolor helps to protect astronauts from accidental injuries while enhancing the wellbeing of female astronauts during menstruation.

4.2.6. Increase Calcium Intake

The space environment causes bone loss, which in turn, causes calcium loss. The time spent in the adverse space living environment is associated with the amount of bone and calcium loss. In-flight astronauts’ calcium intake was often close to or at the planned intake, similar to the recommended intake on Earth [ 47 , 53 , 127 ] despite reduced absorption, increased urinary calcium, and a further risk of kidney stones [ 109 ]. Calcium-rich foods include milk, legume, fish, shrimp, kelp, black agaric, laver, and sea cucumber. Increasing the intake of fruits and vegetables may prevent changes in bone mineral content when adequate calcium is consumed during spaceflight [ 107 ].

4.2.7. Increase Unsaturated Fatty Acids and Decrease Saturated Fatty Acids

Unsaturated fatty acids are superior to saturated fatty acids in preventing metabolic changes, including insulin resistance and inflammation [ 140 , 141 ]. Studies have shown that omega-3 fatty acids [ 120 ] and vitamin E [ 142 ] help facilitate space adaptation [ 142 ]. Omega-3 is a family of polyunsaturated fatty acids, including three types of fatty acids: namely, α-linolenic acid, DHA, and EPA, which are found in linseed oil, vegetable oil, fish oil, seaweed, and leafy greens. Omega-3 contains essential nutrients that cannot be synthesized by the body and must be obtained from food. omega-3 intake has been shown to reduce bone resorption during bed rest [ 120 ]: to obtain plentiful omega-3, fish is the best animal resource, while flax and peony seed oil are the best plant sources. Fruits and vegetables also play an important role in providing omega-3. Providing a diet rich in fruits and vegetables, such as a Mediterranean diet, over the long term will have a positive impact on bones in long-term tasks, while adding omega-3 and fish can help counteract bone loss. Fish and omega-3 have also been found to support bone health protection [ 143 , 144 ], mitigate muscle atrophy, and enhance immune function [ 132 ]. Thus, an increase in the intake of fish may help strengthen the skeletal muscle to support a strong immune system in addition to reducing the risk of cancer [ 145 , 146 , 147 , 148 , 149 , 150 ]. Micronutrients in nutrient-rich foods, such as fruits or vegetables, can also help to combat most physiological disorders caused by microgravity [ 189 ].

4.2.8. Increase Protein Intake to Counteract Muscle Atrophy

Exposure to microgravity reduces muscle mass, volume, and performance [ 47 ]. Weightlessness can lead to changes in skeletal muscle function and structure, such as decreased muscle mass, fatigue, motor nerve stiffness, and autonomic motor ability. Therefore, it is particularly important for astronauts to maintain at least their normal energy supply and protein intake for short-term space missions.

Studies of astronauts on long flights that last more than 100 days suggest that a decrease in protein synthesis may be related to a lack of energy intake [ 129 ]: the data showed that the protein macronutrient compositions at an average of 15%, as recommended by the World Health Organization (WHO), were underestimated by 41%. Therefore, astronauts should intake more protein for long-term space missions. In addition to protecting astronauts’ health, protein is also crucial to their ability to move when they return to earth.

Supplementation with essential branched chain amino acids enhances protein synthesis to help fight muscle atrophy [ 130 , 131 ]: branched chain amino acids stimulate the production of insulin, which also promotes the absorption of amino acids by muscles. Branched chain amino acids also help prevent protein breakdown and muscle loss. Foods containing branched chain amino acids are fish, shrimp, milk, soy, corn, glutinous rice, cauliflower, and so on.

Supplemental animal protein has been shown to reduce the pH of the blood through the oxidation of sulfur amino acids, thus exacerbating bone loss [ 117 ]. Astronauts should limit the amount of animal protein they eat to minimize bone loss while increasing other sources of protein to stay above their normal protein intake level for long-term space missions.

4.2.9. Combat Intestinal Microecology Disorder with Foods Rich in Calcium and Probiotics

Astronauts often suffer from a variety of infectious diseases caused by fungal hypersensitivity or the degradation of protective intestinal flora [ 188 , 216 ]. To combat the microgravity-induced degradation of intestinal flora, Italian space agency researchers developed calcium- and probiotics-rich space food from freeze-dried plain yogurt and uniquely flavored yogurt with blueberries [ 131 ].

4.3. Nutritional Countermeasures for the Effects of Radiation

One of the greatest hazards of space flight is space radiation. Space radiation can cause acute physical damage to human tissues, such as skin bowel marrow and other tissue, leading to cataracts. Radiation can also kill human cells and change the DNA in the body, reducing immunity and increasing the risk of cancer and genetic damage [ 90 , 91 , 92 , 93 , 94 ].

Food does not prevent direct damage from space radiation, but it can help astronauts tolerate low levels of radiation exposure. To prevent or reduce radiation damage from the indirect effect of radiation that produces free radicals, countermeasures can be provided through a diet rich in the following ingredients: natural antioxidants (such as procyanidins), Omega-3 fatty acids, vitamin E, vitamin C, beta-carotene, selenium, and even plants containing dietary fiber. Foods with antioxidant properties include tomatoes, garlic, nuts, oats, blueberries, broccoli, salmon, and green tea. Tonic food rich in a certain vitamin helps enhance the health performance of the human body. One example of such food is buckwheat, which contains high amounts of Vitamin P and selenium. Selenium is an active component of the antioxidant glutathione peroxidase, which can effectively remove free radicals, fight oxidation, and activate the immune system to prevent cancer. Vitamin P can effectively inhibit bacteria and the carcinogenicity of aflatoxin B1. At the same time, selenium can catalyze and eliminate free radicals harmful to the eyes and treat a variety of eye diseases, such as cataract retinopathy. Therefore, foods rich in selenium are promising aviation functional foods.

4.4. Brief Summary of Nutritional Countermeasures to the Adverse Effects of Space Environment

Different health problems are caused by insufficient calories and micronutrient intake. Targeted nutrition countermeasures should be provided to meet the necessary nutritional needs of crew members to prevent the occurrence of diseases to better sustain space missions. While VB6 is most abundant in yeast, it is also found in wheat bran, malt, liver and kidney, rice, potatoes, sweet potatoes, vegetables, carrots, bananas, and peanuts [ 142 ]. VB12 is found in shellfish livers and in all animal sources, such as fish, shrimp, eggs, and milk, as well as a few non-animal sources, such as fermented soy products, mushrooms, and seaweed [ 143 ]. VE is widely found in nuts, lean meat, milk, egg, vegetable oil, wheat germ, green leafy vegetable, sweet potato, yam, and kiwi fruit [ 144 ]. VC is widely found in fresh vegetables and fruits [ 145 ]. The most ideal sources of biotin are yeast, liver, kidney, brown rice, peanuts, beans, fish, and egg yolks [ 146 ]. Iron is concentrated in animal liver, clam, kelp, shrimp, chicken with egg yolk, beans, green vegetables, and fruits [ 147 ]. The main way for the human body to supplement copper is to eat animal liver, shellfish, fish, meat (especially poultry), fruits, tomatoes, green peas, potatoes, shellfish, laver, cocoa, and chocolate [ 149 , 150 , 189 ]. Selenium is most abundant in seafood shellfish, followed by animal viscera and kidney wheat germ. An insufficient energy intake can affect protein turnover, thus increasing protein and individual amino acids. In summary, VB12, biotin, copper, and selenium cannot be sourced from vegetables, which are the only types of fresh space food currently. It is essential for long-term space habitats to support the production of animal proteins, fermented soy products, seaweed, mushrooms, and brown rice with minimal weight, resource, and space requirements. Table 3 summarizes the nutritional countermeasures for the adverse effects of the space environment.

Nutritional countermeasures for the adverse effects of space environment.

4.5. Nutrient Loss during Food Processing and Storage

For long-duration missions, the risk of malnutrition for astronauts comes from the inadequate quantity and quality of the food they intake. Currently, the food items consumed in space are largely processed and stored foods with limited shelf life. For most space foods, NASA requires a shelf life of 18 to 24 months, which is not enough for future deep space missions. Long-term missions require the food shelf life to be extended to 3 to 5 years [ 221 ]. It is a challenge to maintain the quality of most space foods within a span of 5 years. If the food loses quality after the first 2 years, the crew will not get enough nutrition for space missions longer than 2 years even if the food does provide sufficient nutrition for the first 2 years [ 31 ].

Astronauts have suffered from intaking space foods with varying degrees of texture and nutrition loss due to the following [ 31 ]: thermal sterilization during processing, vibration and shock during storage and transportation, and radiation accumulation during long-term storage in space. Existing data show that storage temperature and time have a significant impact on the vitamin content of space food.

The results of an experiment conducted with space food storage over 2 years provided the following insights: (1) when the storage temperature of several fruits and vegetables was 27 °C, the loss rate of VC, VB1, and VB2 was up to 58%; (2) when the storage temperature was 10 °C, the maximum loss rate of vitamin was 38% [ 84 , 151 , 153 ]. Because of its long shelf life, thermally stabilized food is the main type of long-term manned spaceflight food. Thermally stabilized foods undergo destructive heat treatment processes that result in nutrient loss, flavor deterioration, and other changes in food quality. The flavor of food changes with time, mainly manifesting as rancidity, a low aroma, and an overall decrease of flavor [ 38 , 84 , 221 ].

Over 2 years of food storage is significant for nutrient loss in most foods [ 206 ]. According to an experiment conducted to study the degradation of vitamins during storage, there was significant reduction in folate, thiamine, VA, VC, and VK in various space foods for a period over 880 days. After 596 days (about 1.5 years), significant differences in vitamin concentrations were found in tacos, salmon, and roasted broccoli. At the end of the study, the multivitamin also underwent chemical degradation, and riboflavin, VA, and VC were reduced by 10% to 35%. Space radiation has no effect on the nutritional level of any food [ 31 ]. Cooper (2010) stored foods at 22 °C over 5 years and analyzed 24 vitamins and minerals in foods at different times over 1 year, 3 years, and 5 years. The preliminary conclusion is that the thermal stability of foods leads to the degradation of VA and VC, thiamine, and folate, and subsequent oxidation further promotes the degradation of vitamins in storage. In most product packaging, VA continued to decrease during the first year of storage. Similarly, most folate and thiamine levels dropped, and VC levels in all products dropped from 37% to 100%. Nutrient loss at 3 years to 5 years is thus expected to be significant and may lead to undernutrition in the food system. As a result, nutrient loss over 3 to 5 years is expected to be significant and may lead to a decrease in the nutritional contents of the food system [ 153 ].

Conventional methods of storage have failed to maintain the initial quality of food for long-term missions, necessitating research into developing new processing techniques and storage conditions. New methods of food supply may also need to be considered.

4.6. Hazards of Food Packaging and Additives

Packaging plays a vital role in the food supply chain by protecting food from environmental influences such as oxygen, water, light, dust, pests, and volatile matter, as well as chemical and microbial contamination [ 166 , 171 , 172 , 222 ].

4.6.1. Toxicity of Packaging Materials

The packaging forms and basic materials of food used for consumption in space mainly include the following four types [ 166 , 171 , 172 , 222 ]: (1) frozen food packaging using basic materials, such as plastic (OPP, NY, LLDPE, PET, PE), paper, and composite aluminum foil; (2) semi-solid food packaging and hose packaging, including aluminum foil, plastic, and resin; (3) canned packaging using aluminum foil, plastic film, and kraft board; and (4) packaging in bags, aluminum foil, and plastic. In summary, the main food packaging materials are aluminum foil, plastic, resin, and glass, among which aluminum foil and plastic are the most widely used materials.

In recent years, processed and packaged foods have been identified as some of the main sources of human exposure to plasticizers and bisphenols, which have migrated from plastic packaging [ 154 ]. Phthalates are used as plasticizers in many consumer products, mainly in food packaging, flooring, household, and other consumer products [ 223 ]. Bisphenol A (BPA) is used primarily in the production of polycarbonate plastics and epoxy resins, as a protective coating in food cans, and in water and feeding bottles. Neither phthalates nor BPA chemically bind to products. In addition, they penetrate, migrate, or evaporate into indoor air, dust, the atmosphere, and food. Phthalates have attracted public attention over the past few decades because of their potential health risks [ 154 ]. Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP) and Diethyl p-nitrophenyl phosphate (DENP) are listed as compounds with suspected endocrine disrupting functions. The serious effect of bisphenol compounds on liver and kidney function was confirmed in mice. BPA can affect liver and kidney function even at very low doses [ 155 , 156 , 157 , 158 ]. Surprisingly, plasticizers, especially BBP and bisphenols, were detected in high concentrations in foods. Their contamination is widely involved in packaged foods including grains and cereal products, milk and dairy products, fats and oils, fish, and candy. Foods that are high in fat are most affected by BBP [ 159 , 160 , 161 ].

Aluminum foil packaging is a composite material made of various materials and aluminum foil, which is a thin metal film made directly from aluminum. With the extension of temperature and time, acid food and alcohol can cause significant aluminum dissolution in packaging foods. Aluminum dissolves and causes heavy metal pollution to food, harming the human body [ 162 ]. The toxicity of aluminum is manifested in brain, liver, bone, hematopoietic (multipotent) stem cells, and cells [ 163 ]. The health of space residents can only be achieved by eating raw, natural fresh foods without the long-term, slow toxicity from packaging materials.

4.6.2. Health Threats from Food Additives

Long-term space missions require a shelf life of up to 3 to 5 years for food, especially for ingredients that are high in oil and easily oxidized. Packaged food contains food additives, which are (1) synthetic or natural substances added to food for the purpose of improving the quality of food such as color, aroma, and taste, as well as (2) anti-corrosion and processing technology. It remains challenging to preserve food for long-duration missions without a wide range and a significant number of preservative-active substances or carriers. The U.S. space agency recently reduced sodium in food by 90% [ 103 ]. Many food additives are bound to threaten the health of astronauts.

4.6.3. Challenges Associated with New Packaging Technology

There has been a growing demand for unprocessed or minimally processed natural high-quality foods that are preservative-free but have an acceptable shelf life [ 164 , 165 ]. The protective functions of packaging have been refined and improved through the development of new packaging technologies as follows: (1) modified air packaging (MAP) [ 167 , 168 , 169 , 170 ], (2) active packaging (AP) [ 173 , 174 , 175 ], (3) intelligent packaging (SP/IP) [ 174 , 176 , 177 , 178 , 179 ], and (4) the use of nanomaterials for packaging [ 182 , 183 , 184 ]. However, these packaging systems can only extend the shelf life of packaged foods by a few days to a year [ 185 ]. This is far from the 3–5-year shelf life necessitated by long-term missions. In addition, these packaging systems have several disadvantages, such as risk of accidental breakage, the need for additional packaging procedures, and moisture sensitivity, making them unsuitable for use with beverages or wet food [ 166 , 186 , 187 ]. Above all, space missions cannot rely entirely on packaged food.

4.7. Development of Space Food Systems

There are currently two lines of inquiry for developing space food production systems for long-term space missions. One is centered on small-scale aseptic food production systems in weightless settings, such as the ISS and most transit space habitats that cannot produce their own artificial gravity. The other investigates the establishment of large-scale closed-loop ecosystems within planetary surface space habitats on the surface of the Moon and Mars.

4.7.1. Aseptic Food Production Systems for Transit Space Habitats

To effectively use space nutrition as a countermeasure for microgravity-related health risks, the production of fresh foods is necessary to enhance nutrient diversity and dietary acceptability for the astronauts [ 42 , 188 , 191 , 192 , 193 , 224 ]. Since major crops can be dried and preserved for a long time, the production of fresh fruits and vegetables with hydroponic, aeroponic, and substrate culture techniques helps to enhance the food quality and the variety of the menu to ensure that astronauts can acquire sufficient quantities and types of natural vitamins [ 194 , 197 ].

Microgravity requires different approaches to store and circulate nutrient solutions to the root zones of plants in small chambers, motivating the development of many closed-looped small-scale food production systems: the NASA Ames research center has developed a “salad machine” that provides astronauts with fresh salad vegetables such as lettuce, cucumbers, and carrots [ 201 ]. In April 2014, a vegetable production chamber called “VEGGIE” arrived at the ISS. It became the first system to grow plants on the space station. The VEGGIE project is the first step towards building a “self-sufficient” space station. VEGGIE also provides “gardening therapy” for astronauts to relieve stress and depression [ 202 ]. NASA introduced LED growth lights for growing tomatoes and fresh salad greens. The team adjusted lighting conditions to optimize plant growth under a variety of conditions and then replicated these scenes in Advanced Plant Habitats on the ISS to meet the complex requirements of producing food in space [ 203 ]. In 2016, the U.S. applied the cultivation method of the “Plant Pillow” (substrate culture technology) to grow crops in space [ 205 ]. In 2017, the ISS started to produce fresh food with a self-watering hydroponic system called the Passive Orbital Nutrient Delivery System (PONDS); the system uses capillary mat materials to connect the substrate around plant roots with a reservoir containing oxygen-infused nutrient solutions [ 207 ]. Tupperware and Techshot have subsequently developed a semi-hydroponic system that requires less maintenance.

There are many challenges associated with food production and preparation in microgravity. For example, if fresh fruits and vegetables are eaten without proper cleaning protocols, they can be vulnerable to microbial contamination. Eating non-sterile food presents astronauts with some level of risks because the sterilization procedures that work on Earth may not be as effective in space, where microbes can mutate more quickly and exhibit more robust behaviors in microgravity [ 208 ]. A proven method for monitoring the microbiome of fresh space foods is needed to reduce potential health risks associated with potentially harmful food pathogens. Microgravity and the lack of atmospheric pressure also affect the transfer of heat and mass, making it challenging to use common cooking methods to prepare food in space [ 31 ].

Many crops have been successfully grown in microgravity [ 209 , 210 ]: onions, cucumbers, and radishes were cultivated on Salyut 7. The vegetables currently grown by astronauts include tomatoes, strawberries, and lettuce. These crops were included because they have a short growth cycle in space and ripen quickly enough to be edible after 28 days. The astronauts ultimately expanded their selection of edible plants to include a wide range of fruits and vegetables, including wheat, peanuts, soybeans, mizuna, pea, and other food crops. Space nutrition became increasingly more closed-looped as the astronauts’ metabolic wastes were converted into sources of nutrients for food production or even processed food through biotechnology [ 211 ].

4.7.2. Long-Term Food Production Systems as Closed-Loop Life-Support Systems

With perchlorate at levels commonly toxic to plants, the Martian regolith cannot become a viable growing substrate without addressing restricted metal availability and nutrient enrichment [ 212 ]. However, even with nutrient supplementation, none of the three currently available Martian Regolith Simulants (MRSs) are capable of supporting plant growth [ 213 ]. These studies suggest that closed-loop life-support systems will be necessary for supporting food production on Mars. Similarly, the lunar regolith cannot support plant growth effectively without addressing issues associated with potentially toxic elements, pH, nutrient availability, air and fluid movement parameters, and its cation exchange capacity [ 214 ]. Compared to sand and sungro, pioneer plants, such as Sporobolus airoides , have been found to germinate equally well in a new agricultural grade lunar regolith simulant (General Lunar Nearside Highland Non-Agglutinate Regolith Simulant) developed by Off planet Research, LLC, and Saint Martin’s University [ 198 ]. Supplementing closed-loop life support systems with mechanisms for resource separation will help maximize in-situ resource utilization without introducing toxic elements into closed-loop life support systems.

The German aerospace center has developed an advanced closed-loop life support system that uses algae-powered photobioreactors to provide continuous and breathable air in space by converting astronauts’ breath and sunlight into oxygen and food. The system could provide about 30% of the food that an astronaut needs. The concept of the human habitat is based on a symbiotic relationship between humans and plants. Edible plants consume carbon dioxide and release the oxygen that humans need. In return, human waste and non-biodegradable plant matter energy (after decomposition in a microbial tank called a bioreactor) provide nutrients for plant growth. These plants can also provide medicine. However, the effects of gravity, light, atmosphere, soil, and radiation on the growth capacity of plants in this regenerative life support system remain largely unknown [ 197 ].

On the surface of the Moon and Mars, higher plants from regenerative life support systems (controlled ecological life support systems) will be the main food source for astronauts. They include wheat, potatoes, sweet potatoes, peanuts, soybeans, rice, and dried beans. Salad ingredients include tomatoes, onions, spinach, beets, cabbage, carrots, lettuce, and radishes. Food processing equipment suitable for the space environment should take into account safety, power, volume, water consumption, air pollution, waste production, cleanliness, and noise. One such piece of equipment is a multifunctional fruit and vegetable processing system developed by NASA for cutting, heating, separation, and concentration [ 199 , 200 ]: for example, the system can process tomatoes into tomato juice, tomato sauce, tomato slice, and tomato soup.

5. Conclusions

The first major finding suggests that resupplies for long-term space mission are cost-prohibitive although it is technologically feasible for short-term missions. It would be even more challenging and costly to resupply food from the Earth to the Moon or Mars as a destination for roundtrips or long-term stays. The finding implies the need for long-term space nutrition system to rely on self-sufficient bioregenerative systems to produce fresh foods. Such systems can be implemented in situ on the Moon or Mars or in upscaled space habitats with artificial gravity.

The second major finding reveals the inadequacy of existing space nutrition systems for meeting long-term physiological and psychological needs due to the dominance of processed and functional foods. Fresh food materials provide natural vitamins, minerals, dietary fiber, and secondary compounds that are lacking in packaged foods. Packaged food cannot meet the health needs of astronauts during long-term space missions due to the loss of nutrients during food processing, preparation, and storage, as well as the health risks associated with using packaging materials and food additives. At the same time, ready-to-eat space food cannot meet the astronauts’ psychological needs for (1) a sense of familiarity from undertaking their normal eating habits and maintaining their food culture and (2) a sense of community from engaging in food production, preparation, and consumption as social activities [ 190 ]. Therefore, space missions cannot rely largely on packaged food to help astronauts cope with the adverse space environment. While functional food may help to counter some of the aforementioned adverse living conditions in space, it is not economically feasible to carry sufficient functional food for long-term space missions lasting 3 to 5 years. Fresh food production through the use of closed-loop systems remains necessary for providing a diverse range of nutrients while working within the limited payload threshold allowed by each space flight. There is an urgent need for the sustainable production of fresh food with distinctive, original flavors to increase appetite. During long-term space missions, enabling a self-sufficient lifestyle through the use of a nature-based regenerative life support system will help astronauts better adapt to the adverse conditions of the space environment [ 195 , 196 ]. This landscape-based approach to space habitat design helps engender a sense of place attachment from biophilia; that is, the human instinctual attachment to life-like features found in nature. Place attachment can potentially make astronauts more resilient in space psychologically and physiologically to better ensure the success of long-term space missions.

The third major finding is that the current small-scale food production systems used by the ISS to produce fresh food are inadequate for completely replacing packaged food without drastically upscaling the next generation space stations and habitats for long-term space missions to the Moon and Mars. It is necessary to undertake a modular approach to increase the size of transit space habitats for long-term space missions through in-space manufacturing. The generation of artificial gravity will be important to safeguard food safety and crew health by enabling the use of more ecosystem-like closed-loop life support systems without increasing the safety risks associated with a higher likelihood of microbial contamination in microgravity. As artificial gravity and in-space manufacturing become increasingly more feasible, incorporating nature-based environments within a landscape-scale space habitat will be a critical path to providing sufficient fresh food to space inhabitants as not only a form of complex medicine required for long-term psychophysiological wellbeing and but also indispensable countermeasures to the adverse living conditions in space.

Acknowledgments

The authors wish to thank Walter Segovia Matinez for his assistance with coordinating two sets of review outcomes into one coherent set of citations and references and Paria Tajallipour and Bruce Neville for providing suggestions on potential databases and review methods for consideration.

Abbreviations

This research was funded by the Texas A&M Foundation’s Innovation [X] Project grant.

Conflicts of Interest

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Space Food for Thought: Challenges and Considerations for Food and Nutrition on Exploration Missions

The Journal of Nutrition

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Neha Phadtare

Many people wonder how and what the astronauts eat, drink and consume during their space missions at the space station. Space Food and beverage are the variety of food products that are consumed by the astronauts in outer space. Many space missions are carried out to bring about different trends in space foods and beverages. Various parameters are such as the food preparation, characteristics, preservations, packaging, innovations, processed food products, and different case study aspects are taken into considerations. Space food and beverage study also include its types, innovations, challenges, and applications. This study includes the nutritional diet of the astronauts in the space station. space food and beverages also include advancement in the techniques to prolong the shelf life and to the nutritional requirements of the astronauts during the missions. Space food and beverages should be easy to prepare and easy to clean up in microgravity. Space beverages also include a study...

Angelo Casaburri

Hope Rising

This scoping review aimed to identify current evidence and gaps in the field of long-term space nutrition. Specifically, the review targeted critical nutritional needs during long-term manned missions in outer space in addition to the essential components of a sustainable space nutrition system for meeting these needs. The search phrase “space food and the survival of astronauts in long-term missions” was used to collect the initial 5432 articles from seven Chinese and seven English databases. From these articles, two independent reviewers screened titles and abstracts to identify 218 articles for full-text reviews based on three themes and 18 keyword combinations as eligibility criteria. The results suggest that it is possible to address short-term adverse environmental factors and nutritional deficiencies by adopting effective dietary measures, selecting the right types of foods and supplements, and engaging in specific sustainable food production and eating practices. However, to...

73rd International Astronautical Congress

Madhu Thangavelu , Carla Uyeda

The concept architecture presented in this paper is about Creating Human Experience through Food (CHEF) in Space. It is part of promoting Commercial Human Spaceflight Expeditions (CHASE), a USC Fall 2021 team project. The overall plan proposes the early transition of the International Space Station (ISS) operations away from NASA core human spaceflight projects to an university consortium and the private sector. The plan comprises adding private labs experimental and manufacturing modules, and includes a hotel that accommodates space tourists in the future, as mandated by US space policy. The goal of CHEF is to serve freshly prepared gourmet food that provides space travelers with an exceptional dining experience. It addresses the challenges of creating a more palatable meal, providing nutritious and tasty food, and catering to individual's caloric needs. CHEF strategy tailors to individual's cravings of the day, on-orbit. It proposes a food technology system that prepares, cooks, and serves the food in an automated fashion. The use of a pressure cooker concept is introduced to cook food per the space travelers' request in short turnaround cycle, from order to delivery. A mixture of preserved food, raw ingredients and spices are processed to go into an ISS, spacecompliant pressure cooker system that uses solar energy. With the use of existing technologies, such as 3-D printing of food, robotic chef, tele-robot arms, and Astrobees, integrated together, an automated kitchen service is made possible to implement the end-to-end, fresh restaurant-style gourmet food experience. Because of the US space tourism mandates for ISS, and the Gateway and Artemis mission plan for returning astronauts to the Moon, there is now an economic opportunity to build a robotic kitchen in space that caters to space travelers in the future. Together with water and breathable air, good nutrition is critical for human spaceflight. CHEF in Space project's goal is to serve gourmet food in their short or long journeys to space. Food is the vital fuel to support humans and it is imperative that their needs are addressed with the highest priority along with crew safety and wellbeing. For any successful and productive human space exploration or space activity, great tasting fresh meals are a prerequisite for the space traveler, especially as we plan endurance-class missions and tours-of-duty lasting months to years to the Moon, Mars and beyond. Evolving from the ISS, CHEF systems can progress to serve the crew on Gateway and Artemis, followed by endurance-class missions to the Moon, Mars and beyond.

Britt Ahlstrom

As commercial aerospace companies advance toward manned spaceflight, they must overcome many hurdles – not only technical, but also human. One of the greatest human challenges they face is food. Throughout the history of human spaceflight, astronauts have primarily eaten food developed by government space agencies. Now, with manned commercial flights on the horizon, astronauts will be provided with an entirely new diet – one comprised of commercially available, ready-to-eat food. Yet will this diet keep astronauts nourished, satisfied with their diet, and both psychologically and physically healthy? The purpose of this parallel crossover design study was to evaluate (a) nutrient intake, (b) food satisfaction, (c) psychological health, and (d) physical health in commercial aerospace employees (N = 7) as they ate a diet of commercial, ready-to-eat food for four days, as compared to eating as normal for four days. Findings from this study showed that the ready-to-eat diet did not lead to any significant changes in caloric intake, psychological health, or physical health, aside from weight loss. It is not clear whether this weight loss was due to the loss of body fat, muscle, or water. When eating the ready-to-eat food, participants reported being slightly less satisfied with the variety, reported lower cravings for sweets, and reported the food was slightly less hedonically rewarding. In post-study interviews, participants reported they wanted to see more meats, fruits, vegetables, and desserts added to the ready-to-eat diet, so as to provide more meal-like structure. Overall, these findings show the diet could be used in commercial spaceflight after making simple changes. The diet could also be used by individuals in remote areas on Earth and to provide food assistance to individuals in disaster or emergency situations. Due to the increasing popularity of ready-to-eat food around the world, these findings also provide knowledge about the potential consequences of modern eating trends.

Food was and is an essential component in human space exploration. If it had not proved possible to eat and digest in space, none of the long-term space missions of the last four decades would have been achievable. Every country that has sent an astronaut on a mission has used its national foods as a means of stating both their presence and their identity to their colleagues in the programme and their citizens at home: in space, as on earth, food has provided a means of asserting national culture. From the earliest missions, the US and USSR’s differing attitudes to the programme have been reflected in the food provided and the respective administrations’ approaches to feeding in space. The contrast between the US focus on space travel and the USSR’s focus on space living is highlighted through their attitudes to the often vexed question of what astronauts and cosmonauts should be permitted to eat, illustrated by the corned-beef sandwich incident of 1965.

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