FOOD AND WATER Water on the space shuttle
A lot of the water consumed on the space shuttle and space station is recycled.The (WRS) Water Recycling System will reclaim waste waters from the Space Shuttle's fuel cells, from urine, from oral hygiene and hand washing, and by condensing humidity from air. It may sound disgusting but water leaving the space station's purification's machines will be cleaner than what most of us drink on earth. Without such careful recycling 40,000 pounds per year of water from Earth would be required to resupply a minimum of four crewmembers for the life of the station.
"The water that we generate is much cleaner than anything you'll ever get out of any tap in the United States," says Layne Carter, a water-processing specialist. We have practically ultra-pure water by the time our water is purified.
The water purification machines on the Space Shuttles cleanse water in a three-step process. The first step is a filter that removes particles and debris. Second, the water passes through the "multi-filtration beds," which contain substances that remove organic and inorganic impurities. And finally, the "catalytic oxidation reactor" removes volatile organic compounds and kills bacteria and viruses. Once the water is purified, astronauts do everything possible to use it efficiently. On the space shuttle the water pressure may be around half of what it is in a typical household. They don't use faucets on the Shuttle. It's much more efficient. If you're an astronaut, you'll wet the wash cloth with a spray nozzle and then use the cloth to wash your face and hands.
Even with great efforts to conserve and recycle the water in space there will gradually be a lose of water because of inefficiencies in the life support system. If a Space Station has lost water it is replaced by carrying it over from the Shuttle. The Shuttle produces water as its fuel cells combine hydrogen and oxygen to create electricity.
Astronauts eat three meals a day- breakfast, lunch, and dinner. Specially trained people called nutritionist make sure the food has a balanced supply of vitamins and minerals.
Calorie requirements differ for astronauts. For instance, a small woman would require only about 1900 calories a day, while a large man would require about 3,200.
The space shuttle's kitchen is called the galley. The galley serves many purposes. An astronaut can prepare, rehydrate, heat, and store food in the galley. There is an oven and rehydration station in the galley. Of course there is no refrigerator. There are about 100 different food items and about 50 different beverages for the astronauts to choose from.
The rehydration system mixes directly with food and beverage packages to rehydrate them and to provide drinking water for the crewmembers. To rehydrate any food item, the food package is connected to a dispenser needle. A lever arm is located in front of the needle, and while the dispenser needle is poked into the food package, the lever arm activates the "limit" switch which locks into the package so water can be dispensed. A volume switch is used to select the volume of water to be dispensed by the rehydration station. The astronaut can choose hot or cold water to rehydrate each food. Ketchup, mayonnaise, and mustard are provided. Salt and pepper are available in a liquid form. This is because astronauts can not sprinkle salt and pepper on their food in space. The salt and pepper would simply float away. There is a danger they could clog air vents, contaminate equipment, or get stuck in an astronauts eyes, mouth or nose. The first U.S. astronaut to eat in space was John Glenn in April 1962. He ate applesauce packaged in an aluminum tube.
After the water is dispensed inside the container, a waiting period has to pass before the food can be eaten. While the water is rehydrating the food many astronauts kneed the container to spread water more evenly throughout the container.
The oven in the galley is divided into two compartments. The upper compartment is designed for heating at least 14 (rigid) rehydratable food containers. The lower compartment is designed to accept up to 7 flexible packages. A switch turns on and off three oven fans. These fans circulate warm air over a heat sink, providing forced convection heating for the ridged packages. The flexible packages are held against the heat sink by three springloaded plates, and are warmed by conduction. The oven has a heating range of 160-185 degrees Fahrenheit. Each food item flown on board the Shuttle comes with its own cooking instructions.
The main reason NASA uses dehydrated food system on board the Shuttle is because dehydrated food reduces the weight of the carried food items. Engineers plan each pound of weight during lift-off. About 50% of all food items consumed on board the shuttle are dehydrated. The water used to rehydrate the food comes from the fuel cells. The shuttle's fuel cells convert hydrogen and oxygen to electricity with water as a by-product.
Some astronauts say their sense of taste changes in space. It varies from not tasting the same to a complete dislike for a previously liked food or beverage.
There is a lot of planning that goes into preparing food for a Shuttle. Of course, there has to be enough food, the food must be stored properly and nonperishable to avoid spoilage. There must be enough water on board for rehydrating and an oven for warming the food. Astronauts must throw their packages away in a trash compactor inside the space shuttle when they are done eating.