The Space Shuttle Food System

Дата канвертавання26.04.2016
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The Space Shuttle Food System

NASA's Space Shuttle has opened a new era in space travel. The Shuttle takes off as a rocket, orbits the Earth as a spacecraft, and lands as an airplane. Missions on the Shuttle can last from one to 30 days for crews of two to seven astronauts.

To meet the nutritional needs of Shuttle crews, a new food system centers around a galley that has been installed on the mid-deck of the Orbiter's cabin. The galley is a modular unit that can be removed for special flight missions that require extra interior space. It features hot and cold water dispensers, a pantry, an oven, food serving trays, a personal hygiene station, a water heater, and auxiliary equipment storage areas. The galley does not have a freezer as in Skylab, nor a refrigerator.

Preparation of a meal on the Shuttle is started by a crewmember 30 to 60 minutes before mealtime. A full meal for a crew of four can be set up in about five minutes. Heating and reconstitution of the food takes an additional 20 to 30 minutes. The "chef" removes complete meal packages from storage and makes the necessary preparation before serving. Food needing rehydration is given hot or cold water in premeasured amounts. Water for rehydration is given hot or cold water in premeasured amounts. Water for rehydration comes from the Orbiter's fuel cells that produce electricity by combining hydrogen and oxygen gas. Since water is a useable biproduct from the fuel cells, much weight can be saved by sending up food in a dried form for rehydration in space. To simplify food packaging a new rehydratable food pack design is used. The bottom of the package is an injection-molded, high density polyethylene base. A thermoformed flexible lid made of plastic film covers the top. To add water, a large gauge hollow needle is inserted through a septum in the base.

Food needing heating is placed in a forced air convection oven, a new feature for space flight. The maximum temperature of the oven is 82 degrees C (180 degrees F) and it can hold temperatures at 65 degrees C (150 degrees F) for an extended period. The oven can heat containers of different sizes and shapes.

Beverage containers for the Shuttle are identical to the packages for rehydratables. A polyethylene straw is inserted through the same septum that is used for injecting water. When not in use, a clamp closes the straw.

While the astronauts are eating, food containers are held in a food tray that is attached to a table in mid-deck, to the astronaut's lap while seated, or attached to a wall. Eating utensils consist of a knife, fork, spoon, and a pair of scissors for cutting open packages. Food can be seasoned with serving-sized packets of mustard, catsup, mayonnaise, hot sauce, and liquified salt and pepper. Following the meal, food containers are discarded and the utensils and serving trays are cleaned with "wet wipes."

Food System Constraints

The primary objective in designing a food system for the Space Shuttle is to provide food that is safe and nutritious, light in weight and compact, and is packaged in a convenient form that allows easy manipulation in the weightless environment of an orbiting spacecraft. To achieve this objective requires a careful consideration of three important factors: biological, operational, and engineering. Under each factor are many constraints that affect the final choice of food and how it is packaged.

The biological factor in food design requires the food to be both safe and nutritious. It should also appeal to the crew's sensory preferences. The food must be easy to inject and digest and not cause any hygiene or gastroenterological problems.

The operational factor relates both to the food and the nature of its packaging. The package must be light in weight (engineering factor) but provide for protection and stability of the food in storage for periods that might last well over 30 days. Food must be easy to prepare and require little crew attention. Easy disposal of waste food and used packaging material is another constraint.

The engineering factor has to do with not only the weight of the food and packaging but how compact it is for storage. Thirty day missions of the Shuttle will require large amounts of food. The food and packaging must survive the temperature pressure, acceleration, and vibration of a Shuttle flight. Still another constraint is the quantity of water needed for rehydration.

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