Why Is Space Food Dried?

Space travel poses inherent challenges, including limited storage space and zero gravity, which make normal food preparation and consumption impossible. Freeze-dried food requires little preparation. It has other desirable characteristics, including light weight and easy transportability.

History

• In 1938, Nescafe invented freeze-drying to store coffee. During World War II, freeze-drying preserved blood plasma and medications without refrigeration. Early freeze-dried foods for space travel included powders and small cubes that crumbled and floated away. They were also hard to rehydrate, and the astronauts disliked eating from squeeze tubes

Preservation by Freeze-Drying

• A freeze-drying machine forms small instead of large ice crystals, thus limiting damage to the cell structure of the food. A vacuum then completely dries the food by forcing the water in the ice to vaporize. The switch to airtight packaging improved the quality of the contents and made them easier to reconstitute.

Improvement of Space Food

• The Gemini crews had a menu that included freeze-dried shrimp cocktail, chicken and vegetables and pudding. Astronauts had hot water for the first time, which facilitated meal preparation and improved taste. The crews could also use spoons to eat from special plastic containers.

Preparation Time

• The space shuttle menus include freeze-dried beef stroganoff, stews, chicken teriyaki, tortillas and rice pilaf, all precooked. Astronauts reconstitute the food packets at a needle-equipped station or heat them in an electric warmer. The contents don't float away and cleanup is minimal. Future crews can use any extra stored food packets. They have a shelf life of at least 2 years.

Nutrition and Taste

• The combination of freeze-drying and better packaging has resulted in more food choices, which also taste much better while providing the Recommended Dietary Allowances of nutrients for each crew member. Freeze-dried food retains most of its nutrients and has intense flavor.