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21st CENTURY EXPLORER
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Why do astronauts eat tortillas instead of bread?
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WHY DO ASTRONAUTS EAT TORTILLAS INSTEAD OF BREAD?

Subject Matter Expert: Scott Smith and Vickie Kloeris

Food is a basic need. Having enough food while traveling has always been a problem for explorers. In addition to having enough to eat, explorers also need ways to package and store food. What can be done to make sure the food won’t spoil? Early explorers dried and stored food in cool places. They also used sealed containers.

Some of these same methods are still being used to store food onboard the space shuttle and the International Space Station.

Originally, all foods eaten by astronauts in space were in the form of bite-sized cubes, freeze-dried food, or semi-liquids inside toothpaste-type tubes. Sound tasty? As space missions continued, the food became “better” in variety, taste, and texture. The choices continue to grow. Astronauts can now choose from more than 70 different kinds of foods and 20 different beverages.

What kinds of foods make good space food? Of course taste is important, but foods are also chosen for their nutritional value. Space food must also be easy to package and store.

Space food is grouped into several different categories. Foods may be rehydrated or freeze-dried, like “astronaut ice cream.” If a little bit of water is left in the food to keep it soft, like dried fruit, the food is categorized as “containing intermediate moisture.” Some foods may be in their natural form, ready to eat right out of the package, like bite-sized crackers and nuts.

Other foods are processed once they’re packaged, such as irradiated and thermostabilized foods. Both processes help sterilize foods. Food that is irradiated is sterilized by radiation, like smoked turkey. Thermostabilized foods, like grilled chicken for fajitas, are sterilized with heat to destroy bacteria.

Astronauts get to taste-test foods before their space mission. With such a variety of foods, space shuttle astronauts may choose different foods for every meal during the mission. An average space shuttle mission lasts seven days. Astronauts on the International Space Station may have to repeat meals on their 30-day menu for their 4--6 month mission.

The reduced gravity of space also affects the way foods are packaged and served. In space, foods that crumble when eaten are avoided. Crumbs and liquids can damage equipment or be accidentally inhaled by astronauts as they float inside the spacecraft. Space is no place for a peanut butter and jelly sandwich. The breadcrumbs from the sandwich can cause trouble. Peanut butter on its own, though, is okay. Sticky food can be eaten with a fork or spoon.

NASA has used flour tortillas on the space shuttle since the 1980s. These special tortillas are designed to take the place of crumbly bread. Picture trying to make a sandwich with two slices of bread. In space, you’d need three hands to do it. Tortillas work great and are a favorite with the astronauts. And …on the ISS, they still taste good after being stored for up to 18 months! Add some picante sauce and hot sauce, and you’ve created fajitas, one of the astronauts’ favorite meals.

Packing food for a trip to Mars will offer even greater challenges. A space flight to Mars will keep astronauts away from Earth for 2 to 3 years. How will food be supplied? Growing and processing food is one option. Researchers believe that the best plants for a long mission are soy, peanuts, potatoes, tomatoes, and wheat. These choices are not only good sources of food but also contain oils that can be used with other foods. They can also be processed into a variety of other food products such as flour and soy milk cheese. Scientists are studying and carefully choosing which plants to grow in a spacecraft.

Food is not only a basic need but a comforting reminder of home. Scientists continue to increase space food choices and look for the best foods for a long-duration flight. Many types of food currently eaten by astronauts are very similar to what you eat on Earth.

It’s important that all crew members have food that keeps them healthy and happy. Astronauts traveling in space are no different than you or me when it comes to needing tasty and nutritious food.

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