9.2.2.2 The following document was updated on 02-21-89 and contains 4541 characters. FOOD Background, 1-3 Concepts Eating is essential to survival. The food astronauts take into space must be lightweight require little storage space be nutritious be convenient to use need no refrigeration Dehydrated Foods for Space Travel Foods are dehydrated to meet weight restrictions for the Space Shuttle liftoff. They are later rehydrated in orbit when they are ready to be eaten. Water used for rehydration comes from the Shuttle's fuel cells. The fuel cells produce electricity by combining hydrogen and oxygen, resulting in water. Since water is an available by-product from the fuel cells, it is possible to send food in a dried form for later rehydration. More than a hundred different food items, such as cereals, spaghetti, scrambled eggs, and strawberries, go through this dehydration/rehydration process. When a strawberry is freeze-dried, it remains full-size in outline, with its color, texture, and quality intact. It can be rehydrated with saliva as it is chewed or by adding water to the package. Twenty varieties of drinks, including tea and coffee, are also dehydrated for use in space travel. But pure orange juice or whole milk cannot be included. If water is added to dehydrated orange crystals, there is no rehydration mixture--just orange "rocks" in water. If whole milk is rehydrated, the dried milk does not dissolve properly. It floats around in lumps and has a disagreeable taste. So skim milk must be used. Back in the l960s, General Foods developed a synthetic orange juice called Tang, which could be used in place of orange juice. Other Foods for Space Travel Shuttle food items are brought aboard in several different forms: NATURAL FORM Examples are graham crackers, pecan cookies, peanut butter, candy, gum THERMOSTABILIZED Cooked at moderate temperatures and sealed in cans. Examples are tuna fish, canned fruit in heavy syrup. IRRADIATED Preserved by exposure to ionizing radiation. Examples are meat and bread. INTERMEDIATE MOISTURE PROCESS Removing part of the water. Examples are dried apricots, pears, peaches Salt and pepper are packaged in liquid form because crystals would float around the cabin. You may want to mention that tobacco and liquor are barred from the Shuttle. Packaging Food for Space All food in space must be packaged in individual serving portions that allow easy manipulation in the weightless environment of an orbiting spacecraft. Packages can be off-the-shelf thermostabilized cans, flexible pouches, or semirigid containers. Food Preparation The variety of food carried into orbit is so broad that crew members enjoy a seven-day menu cycle. A typical dinner might consist of a shrimp cocktail, steak, broccoli, rice, fruit cocktail, chocolate pudding, and grape drink. To prepare the meal, the mission specialist chef takes a big plastic overwrap out of the food locker. The package is attached to a worktable. Inside the overwrap are four smaller plastic overwraps, each holding a complete meal of seven separate containers. Using a hollow needle attached to the hot water outlet, the chef injects a prescribed amount of water through a narrow passageway into the plastic bowls of dehydrated broccoli and rice. The chef kneads the packages through their flexible plastic tops and secures them in the oven along with the four precooked steaks. The steaks are packaged in flexible aluminum-backed plastic bags, called flex-pouches. The heat in the oven is 82 degrees Celsius, which does not harm the plastic containers. A fan circulates air so that the food is heated evenly. While these items warm in the oven, the mission specialist takes four trays from the galley and attaches them by magnets or clamps to a portable dining table hooked to the lockers. The mission specialist then adds cold water through the hollow needle to rehydrate the bowls of shrimp, chocolate pudding, and grape drink. A plastic straw with a clamp on it is inserted into the passageway of the grape drink. These cold items, along with the cans of fruit cocktail, the silverware, and a can opener, are assembled on the trays and held by magnets or Velcro tape. When the heated foods are ready, it is dinner time.