07/09/2021
What Is Space foods?
From the beginning of space travel, diets and nutrition, food preservation methods, food packaging methods, food processing methods etc. have evolved greatly. This article summarizes how food systems have evolved from history, current situation and how this can be developed for future explorations.
In the early days of the space programs, Project Mercury became more important as the Mercury astronauts contributed to the development of space food. They tested the physiology of chewing, drinking, and swallowing of solid and liquid foods in a microgravity environment. These astronauts found themselves eating bite-sized cubes, freeze-dried foods, and semi-liquids in aluminum toothpaste-type tubes. The tube foods offered many challenges to new food developments and new food packaging. The food was unappetizing, and there were problems when they tried to rehydrate the freeze-dried foods. First, a method of removing the food from the tube was needed. A small straw was placed into the opening. This allowed the astronauts to squeeze the contents from the tube directly into their mouths. This aluminum tube packaging often weighed more than the food it contained. Because of this, a lightweight plastic container was developed for future flights. During the later Mercury test flights, bite-sized foods were developed and tested where the cubes could be rehydrated by saliva secreted in the mouth as food was chewed. Also the cubes were coated with an edible gelatin to reduce crumbling. These foods were vacuum-packed into individual serving-sized containers of clear, four-ply, laminated plastic films for storage. This packaging provided protection against moisture, loss of flavor, and spoilage.
The major advancements in food items during the Gemini period were more variety and improved packaging. Adequate nutrient intake became a health concern with extended space flights in the Gemini program. Each crew member was supplied with 0.58 kilograms of food per day. Some examples of the food flown on Gemini missions included grape and orange drinks, cinnamon toasted bread cubes, fruit cocktail, chocolate cubes, turkey bites, apple-sauce, cream of chicken soup, shrimp cocktail, beef stew, chicken and rice, and turkey and gravy. Mainly freeze-drying techniques were used. To rehydrate the freeze-dried food, water was injected into the package through the nozzle of a water gun. The other end of the package had an opening in which the food could be squeezed out of the package into the astronauts’ mouth. After the meal is completed, germicidal tablets were placed inside the empty package to inhibit microbial growth on any leftovers. The advantages of freeze-dried foods were having similarities in appearance (including color, taste, shape, and texture) to the original food item, lightweight, longer shelf life and ability to store at room temperature.
The preparation, handling, and consumption of space foods during the Mercury and Gemini missions provided valuable experience for the further development of space foods for future space flights. The Apollo program used food packages similar to those used on Gemini, but the varieties of foods were considerably different. Some of the foods consumed on Apollo were coffee, bacon squares, cornflakes, scrambled eggs, cheese crackers, beef sandwiches, chocolate pudding, tuna salad, peanut butter, beef pot roast, spaghetti, and frankfurters. Rehydratable foods were encased in a plastic container referred to as the spoon bowl. Water was injected into the package through the nozzle of a water gun. After the food was rehydrated, a pressure-type plastic zipper was opened, and the food was removed with a spoon. The moisture content allowed the food to cling to the spoon, making eating more like that on Earth. Another new package, the wet pack or thermostabilized flexible pouch, required no water for rehydration because water content was retained in the food. There were two types of thermostabilized containers: a flexible pouch of a plastic and aluminum foil laminate and a can with a full panel pullout lid. A disadvantage of the canned products was the added weight, which was approximately four times that of rehydratable food. With these new pack-ages, Apollo astronauts could see and smell what they were eating as well as eat with a spoon for the first time in space.
The dining experience on Skylab was unlike any other space flight. The Skylab laboratory had a freezer, refrigerator, warming trays, and a table. Eating a meal on Skylab was more like eating a meal at home. Foods consisted of products such as ham, chili, mashed potatoes, ice cream, steak and asparagus. The supply of food onboard was sufficient to feed three astronauts for approximately 112 days. The menu was designed to meet each individual astronauts daily nutritional requirements based on age, body weight, and anticipated activity and each astronauts’ caloric intake was 2,800 calories a day. Skylab foods were packaged in specialized containers. The rehydratable beverages were packaged in a collapsible accordion-like beverage dispenser. All other foods were packaged in aluminum cans of various sizes or rehydratable packages. To prepare meals, the Skylab crew placed desired food packages into the food warmer tray. This was the first device capable of heating foods during space flight.
For the Space Shuttle program, a more Earth-like feeding approach was designed by updating previous food package designs and hardware items. Food variety expanded to 74 different kinds of food and 20 kinds of beverages. A standard Shuttle menu is designed around a typical 7-day Shuttle mission. Astronauts may substitute items from the approved food list to accommodate their own tastes or even design their own menus, but these astronaut-designed menus are checked by dietitians to ensure that they provide a balanced supply of nutrients. Rigid square rehydratable packages were being used but they became problematic on longer missions. Packages made of a lighter flexible material were developed then which is made of flexible plastic and have a valve for inserting water. In addition, a trash compactor was developed to reduce the volume of the trash. On the Shuttle, food is prepared at a galley. This modular unit contains a water dispenser and an oven. The water dispenser which can dispense hot, chilled, or ambient water is used for rehydrating foods, and the galley oven is used to warm foods to the proper serving temperature. A meal tray is used as a dinner plate. The tray attaches to the astronaut’s lap by a strap or can be attached to the wall. Eating utensils consist of a knife, a fork, a spoon, and a pair of scissors to open food packages.
The International Space Station (ISS) becomes operational on a full-time basis. Food and other supplies are re-supplied every 90 days by the Multi-Purpose Logistics Module (MPLM). Most of the food planned for the ISS are frozen, refrigerated, or thermostabilized. Similar to the Space Shuttle, the ISS beverage package is made from a foil and plastic laminate to provide a longer product shelf life. Water mixes with the drink powder already in the package through an adapter which is used to add water and it also holds the drinking straw for the astronauts. The food package is made from a microwaveable material. The top of the package is cut off with a pair of scissors, and the contents are eaten with a fork or spoon. The astronauts use a special tray to hold their food during preparation and eating. These trays are different from those used on the Space Shuttle because they (ISS) have a table available; the Space Shuttle does not.
When talk about the future of space foods, the transit food system will be similar to the International Space Station food system with the exception that products with three- to five-year shelf lives will be needed. Once crewmembers arrive on the surface and establish living quarters, they can start growing crops. Possible crops that could be grown and harvested include potatoes, soybeans, wheat, peanuts, dried beans, lettuce, spinach, tomatoes, herbs, carrots, radishes, cabbage and rice. Once the crops are processed into edible ingredients, cooking will be done in the spacecraft’s galley to make the food items and most of the diets will become vegetarian without the dairy products. Disposal of used food packaging will be an issue since there will be no Progress vehicles. So Packaging materials will be used that have less mass but sufficient barrier properties for oxygen and water.
Thus, with the day to day breakthroughs in food science and technology, space foods are bound to change further, giving astronauts a similar food experience to Earth.
