Course:FNH200/Projects/2025/Food In Space: How do we eat on Mars?

Advancing Food Systems for Space Exploration: Challenges, Innovations, and Human Factors

Space food has evolved significantly since its introduction in the 1960s, reflecting the intersection of food science, engineering, and human spaceflight. What began with bite-sized cubes and paste in aluminum tubes during Project Mercury has developed into a diverse array of meals aboard the International Space Station (ISS). Technological advances have expanded not only the variety and palatability of foods available in space, but also efforts to make food systems more sustainable for future long-duration missions.

During the Apollo Program (1968-1972), NASA introduced rehydratable packages and thermostabilized pouches, which allowed astronauts to consume wet meals or use utensils in general. Skylab later featured innovations such as warming trays and freezers, enabling a more familiar dining experience. Today the ISS offers customized menus designed to accommodate individual nutritional needs and preferences.

Dehydrated food that was scheduled to be brought on the Apollo 11 moon landing

Processing

Astronauts living and working in space depend on specially designed foods that meet a variety of physical, technical, and psychological needs. Space foods today must be compact, long-lasting, and safe for consumption in microgravity, with a shelf life of 5 years or longer. Several processing methods ensure the food remains compact, nutritious, and palatable.

1. Dehydration: A common way of preserving space foods is through dehydration. In addition to prolonging shelf life, dehydration allows foods to be more compact, portable, and lightweight. Dehydration preserves food based on the principle that microorganisms require free water to grow.

2. Thermostabilized Foods: Meals are heat-treated and vacuum sealed to destroy microorganisms that cause spoilage, allowing for long shelf life without refrigeration. Common examples include beef stew, pasta, and scrambled eggs. NASA’s food lab adapts them from military-style rations, but modifies the nutrition for astronauts’ needs.

3. Freeze-Dried & Rehydratable Foods: Freeze-drying is a method of dehydration often used for space food, which is performed by sublimating frozen water out of foods, leaving behind a porous product capable of rehydration. This allows the nutrition, colour, and taste of foods to be preserved and remain palatable while meeting nutritional needs. To keep meals light and compact, many meals are freeze-dried and rehydrated with water onboard including soups, oatmeal, and rice .

4. Irradiated Foods: Irradiation is used to sterilize space food such as beef, smoked turkey, and pork by destroying microbial cells and growth. However, this method can alter flavour and destroy nutrients, which leads irradiated products to undergo further processing through food additives to increase nutrition. While not used as often as other food types, they are a reliable option for variety and taste.

5. High Pressure Processing: Space foods can also be processed through high-pressure processing (HPP), which involves putting foods under high pressures of 200-600 MPa, killing microorganisms. This method can also preserve food without sacrificing nutrition or flavour, with some accounts stating that foods taste better after HPP is performed.

Mechanism used in high-pressure processing

6. Natural Form Foods: Snacks like nuts, granola bars, and dried fruits don’t need modification for space. However, crumbly foods such as bread are avoided since floating crumbs pose a risk to both equipment and crew members in microgravity. Tortillas are the alternative as they are flexible and crumb-free.

7. 3D Printing: An emerging method of space food production where foods can be processed into edible ingredients and powders, then placed in a cartridge and printed layer by layer in zero-gravity. This method of food processing also allows much greater customization and complexity for space meals, catering to the nutritional needs of each astronaut.

Packaging

Packaging plays a crucial role in preserving space food by preventing exposure to moisture, light, oxygen, and microbes.

In the Mercury program, the first American astronaut project, foods were processed into cubes and then packaged into aluminum and Kraft paper. Semi-liquid foods were made into pastes or purees and packaged in aluminum tubes with polystyrene extensions that helped squeeze out the food. Early space packaging prioritized containment over preservation but today, packaging must also ensure a long shelf-life for missions to Mars and beyond.

Food packaging on Project Mercury

One such packaging commonly used for space food is retort pouches. They are lightweight and are able to serve as a barrier between the food and the outer environment, making them highly suitable for space food packaging. This form of packaging is used for foods that are irradiated or heated.

Retort packaging

Future forms of space food packaging currently being developed are nanomaterial-based which have the potential to fit all criteria of being lightweight, high-strength, and protecting food against outside influence, extending shelf-lives by 3-5 years. One nanomaterial in development is a form of cellulose produced by bacteria, used as a protective film over space foods that forms a barrier against moisture and oxygen, increasing the shelf-life of foods. This material also has a porous structure, which enables it to be filled with antimicrobial agents, further preventing food deterioration.

Bacterial cellulose

Perception of Flavours

The way humans perceive flavour from food comes from both taste and smell. The no-gravity environment in space causes the fluids inside astronaut’s bodies to shift leading to blockages in their nasal passages and reducing their ability to smell and therefore perceive flavour. Due to this limitation, certain condiments have been used to give food a stronger flavour. Hot sauces, BBQ, and soy sauce, as well as honey, have all been used in space to strengthen flavours.

Chris Hadfield adding hot sauce to a burrito on the ISS

As of late, astronauts perform food evaluations and are able to sample a variety of foods from a menu months before their flight.

Food Production In Space

Producing food in space is essential for a long-duration mission, like a round trip to Mars, which could take over three years. Since gravity, soil, and sunlight are limited or absent, astronauts rely on controlled-environment agriculture (CEA). Examples of these are hydroponics (growing in nutrient-rich water), aeroponics (mist-based growth), and bioreactors for microalgae and fungi. These systems recycle water, minimize waste, and reduce resupply needs.

Hydroponics research and practical system

Aeroponics research and practical system

NASA’s veggie experience on the ISS demonstrated successful cultivation of red romaine lettuce and other crops under LED lighting, marking a key step toward sustainable space farming and indicating that plants can grow in microgravity.

ISS grown red romaine lettuce

For future Martian greenhouses, using regolith (Martian soil) poses challenges. Native Martian soil contains perchlorates, which are toxic to humans and plants, requiring pre-treatment before use.

Hypothetical Mars soil before and after treatment

Looking ahead, researchers are exploring multi-trophic systems including microalgae, insects, and cellular agriculture to create close-loop food ecosystems, turning spacecraft into self-sufficient ecosystems.

Beyond the Physical

Food in space serves functions beyond physical sustenance. In confined, high stress environments like the International Space Station (ISS), food fosters emotional comfort and social connection. Celebratory meals for birthdays or cultural holidays are common and boost crew morale. In fact, space agencies have incorporated culturally diverse foods, such as Russian borsch and French chocolates, into menus to acknowledge the varied cultural backgrounds of astronauts.

As missions extend to Mars and beyond, the emotional role of food will become even more crucial. Crews may spend many more years away from Earth, making sensory familiarity and personalized meals important. Studies have shown that food in space can help maintain mental well-being by reducing stress and strengthening interpersonal bonds among crew members. Thus, future space food systems must consider psychological and cultural factors in addition to nutritional needs and technological feasibility.

STS-98 Pilot Kenneth D. Cockrell is preparing breakfast burritos for his crewmates	Expedition 53 crewmembers (left to right) Mark T. Vande Hei, Sergei N. Ryazanski, Aleksandr A. Misurkin, Paolo A. Nespoli, Joseph M. Acaba, and Randolph J. Bresnik show off the pizzas they created onboard ISS
Expedition 50 astronaut Pesquet enjoys macarons delivered for his birthday	Expedition 53 crewmembers (left to right) Mark T. Vande Hei, Sergei N. Ryazanski, Aleksandr A. Misurkin, Paolo A. Nespoli, Joseph M. Acaba, and Randolph J. Bresnik show off the pizzas they created onboard ISS

Key Findings

• Space food has evolved from purees and cubes to diverse, shelf-stable meals tailored for nutrition, taste, and microgravity.
• Processing methods like freeze-drying, thermostabilization, irradiation, and high-pressure treatment ensure safety, shelf-life, and compactness.
• Advanced packaging (like retort pouches and nanomaterials) prevents spoilage and supports long missions.
• Microgravity dulls smell, reducing taste perception. Astronauts use bold condiments and undergo food preference testing pre-flight.
• Food boosts morale as shared meals, cultural dishes, and celebrations help support mental health in space.
• Sustainable systems like hydroponics, bioreactors, and 3D food printing aim to reduce Earth's resupply needs and enable Mars missions.

Exam Question

A common method of space food packaging uses retort pouches, which are made of three layers consisting of polypropylene, aluminum foil, and polyester. How do these materials extend the shelf-life of space foods to the minimum required amount of 5 years? (Select all that apply).

1. The aluminum foil protects the food from light and gases, which can deteriorate the food
2. The polyester layer is a printable surface, allowing designs to be easily put onto the packaging
3. The polypropylene layer protects the food from the zero-gravity space environment, which can deteriorate the food
4. The polyester layer protects the food from physical stress, which can deteriorate the food
5. Retort packaging is flexible and lightweight, making it suitable for long-term space missions

This question should be on the exam because it gives students a chance to connect concepts regarding food deterioration and preservation with a new scenario. By answering this question correctly, students can show that they have an understanding that light, gases, and physical stress directly contribute to the extension of shelf-life in foods.