What do astronauts eat in space to stay healthy?

January 12, 2026 •

3 min read

Astronauts can lose up to 20% of their muscle mass and bone density during a long mission due to microgravity. This is why the question of what do astronauts eat in space to stay healthy is critically important, with their diet meticulously planned to counteract these physiological changes.

Quick Summary

To remain healthy in microgravity, astronauts consume a diet meticulously designed by food scientists, featuring shelf-stable meals that combat bone and muscle loss while ensuring balanced nutrition and psychological well-being.

Key Points

Counteracting Microgravity: Astronaut diets are specially formulated to combat bone density loss and muscle atrophy caused by weightlessness, often supplemented with extra calcium and Vitamin D.
Diverse and Nutritious Menu: Modern space food includes a wide variety of meals, from freeze-dried favorites like mac & cheese to international cuisine, ensuring balanced nutrition and high morale.
Advanced Food Processing: Techniques like freeze-drying, thermostabilization, and irradiation ensure food is nutritious, safe, and has a long shelf life without refrigeration.
Crumbless Design: To prevent floating debris from damaging sensitive equipment, items like tortillas are preferred over bread, and condiments like salt and pepper are in liquid form.
Psychological Benefits: Beyond physical health, a varied and tasty menu, including occasional fresh produce, provides significant psychological benefits for astronauts during long missions.
Addressing Taste Alterations: Because microgravity can dull an astronaut's sense of taste, spicy condiments like hot sauce are often popular choices.

Overcoming the Challenges of Space Dining

Eating in space is a complex science, balancing nutritional needs with the unique challenges of a microgravity environment. In space, fluids shift towards the upper body, mimicking a head cold and dulling astronauts' senses of taste and smell. This, combined with the physiological stress of spaceflight, necessitates a diet that is not only packed with nutrients but also palatable and varied enough to boost morale. Space food systems have evolved significantly from the early days of pureed tubes to today's diverse menu, which includes comfort foods from different cultures.

The Science of Space Food Preservation

NASA and other space agencies use a variety of preservation techniques to ensure food is safe, lightweight, and has a long shelf life without refrigeration.

Freeze-Drying (Rehydratable foods): This process removes 97% of a food's water content, making it incredibly light and compact. Foods like shrimp cocktail or vegetables are vacuum-sealed, and astronauts inject hot or cold water to rehydrate them before eating.
Thermostabilization: Similar to commercial canned food, this method involves heat-treating food to destroy microorganisms and sealing it in flexible pouches. Meals such as meatloaf and ravioli can be eaten directly from the pouch after being warmed in a conduction oven.
Natural and Intermediate Moisture Foods: These include ready-to-eat items like nuts, cookies, and dried fruits, which have low water content to inhibit microbial growth. Tortillas are a popular choice as they produce no crumbs, which could otherwise float and interfere with equipment.
Irradiated Foods: Meats and some dairy products are treated with ionizing radiation to kill bacteria, extending their shelf life while minimizing packaging.

Nutritional Strategies for Astronaut Health

In microgravity, the human body undergoes significant changes, including bone demineralization and muscle atrophy. Astronaut diets are specially formulated to mitigate these effects.

Macronutrient Balance: Diets are tailored to provide a balanced intake of carbohydrates (50–55%), protein (0.8 g/kg), and fat (25–35%) to meet energy needs, support muscle maintenance, and aid metabolism. Extra energy is provided for extravehicular activities (EVAs).
Mineral and Vitamin Supplementation: High doses of calcium and vitamin D are essential to counteract bone loss. Recent studies also suggest that diets rich in antioxidants like vitamins C and E help combat the oxidative stress caused by radiation exposure in space.
Enhanced Diet Protocols: NASA's HERA analog missions have shown that a diet rich in fruits, vegetables, fish, and omega-3 fatty acids can improve cholesterol levels, cognitive function, and microbiome stability, highlighting the benefits of a diverse, nutrient-dense menu.

Challenges and Innovations in Space Food

Beyond basic nutrition, food must also be safe, easy to handle, and appealing to astronauts during extended missions. For instance, condiments like salt and pepper must be in liquid form to prevent them from floating away and potentially damaging sensitive equipment. Packaging is also key, with flexible, lightweight pouches and single-serving containers used to minimize waste and storage space. Food scientists constantly innovate, with research ongoing into creating food with up to a five-year shelf life for future Mars missions. Technologies like 3D printing of nutritious fungal protein are also being explored.

Earth Food vs. Space Food Comparison Table


Feature	Earth Food	Space Food
Preparation	Cooking, baking, refrigeration	Rehydration, heating in ovens, ready-to-eat
Shelf Life	Days to weeks (fresh), months (preserved)	Months to several years (shelf-stable)
Packaging	Varied (glass, plastic, paper, cardboard)	Flexible, vacuum-sealed pouches and cans
Nutritional Focus	Freshness, variety, taste	Density, stability, targeted nutrient intake
Physical Properties	Subject to gravity (crumbs, spillage)	Engineered to prevent crumbs and spills

The Future of Astronaut Dining

As missions extend further into deep space, reliance on resupply missions from Earth will be impractical. This has spurred research into new food production methods for long-duration travel, such as growing crops in space and developing on-demand food manufacturing systems. A balanced and appealing diet is vital not only for physical health but also for the psychological well-being of crew members, helping them cope with the confinement and stress of isolation. The evolution of space food demonstrates a deep understanding of the human body's needs in the most extreme environment, ensuring astronauts have the fuel to continue exploring. You can learn more about the latest innovations in space nutrition by visiting the official NASA Space Food Systems website.

Frequently Asked Questions

In microgravity, astronauts experience bone and muscle mass loss, while fluids shift to the upper body, causing a stuffy nose sensation that dulls their sense of taste. The diet is designed to mitigate these physiological changes.

Most space food is packaged in flexible, vacuum-sealed pouches or cans that are lightweight and compact. This prevents crumbs and liquids from escaping and damaging equipment.

Flour tortillas are among the most popular food items. They are versatile and do not produce crumbs, making them safe for consumption in microgravity.

Yes, some fresh foods like fruits, vegetables, and lettuce are delivered to the International Space Station periodically and must be consumed quickly. Growing fresh crops on the ISS also provides psychological benefits.

Beverages are rehydrated from a powder inside a sealed pouch. Astronauts use a straw with a one-way valve to prevent the liquid from floating out in microgravity.

An astronaut's daily caloric intake can range from 1,900 to 3,200 calories, determined by food scientists based on their weight, gender, and specific mission needs.

Space food is prepared in a galley using water injectors to rehydrate freeze-dried meals and a conduction oven to warm thermostabilized dishes. Traditional cooking methods are not possible in space.