One important difference between space and ground is that it is microgravity or weightless environment in space. The astronauts' living environment in space is very different from the living environment on the ground. What kind of situation is the astronaut living in and living in the closed cabin of a spacecraft isolated from the outside world? What do the astronauts eat in space? How to sleep? How to go to the toilet?
1 How the astronauts drink water in space
In the microgravity environment of space, you must never use a cup to drink water, because in the microgravity conditions, water does not flow down, so the water will not automatically flow into the mouth when the cup is inverted. Drinking water in space is generally sucked by a straw. The beverage container has a water injection hole at one end. The astronaut uses a plastic pipette to insert the water injection hole to drink.
2 How do the astronauts eat in space?
In the early days of space flight, some scientists speculated that people may have difficulty swallowing under microgravity conditions, and foods that are eaten may stick to the throat and swallow. Later practice proved that these conjectures were wrong, that it was not difficult for people to eat in space and there was no problem with swallowing. Because people swallow food by muscles, they have little to do with gravity. And according to the astronaut, swallowing food under microgravity seems to be easier than on the ground.
Under microgravity conditions, food can be easily removed from open containers using plain cutlery, especially sticky sauces, thick soups and juices, puddings, and cuts, which are easier to remove with spoons and forks. As long as you are careful, you can use the spoon to remove it and send it to the entrance without floating or spilling halfway. However, if food is not souped or sticky, it may float or fly around. In addition, if the food contains too much vegetable oil and the oil floats on the surface, the oil droplets may splash out. The researchers also found that using spoons to take food under microgravity is more reliable than using forks. For example, using a spoon to hold milk, if the spoon is shaken from side to side under microgravity, the milk will not be shaken out; but if it is on the ground, the milk will be shaken to the ground. Experts believe that this is because the movement of liquids under the conditions of microgravity is mainly controlled by surface tension, cohesion and adhesion; on the ground, it is mainly controlled by the gravity of the earth.
Early space foods were pasty foods such as apple sauce, beef sauce, pureed vegetables and meat dishes. These pastes are packaged in plastic bags. At one end of the bag, there is a feeding tube. The plastic bag is squeezed by hand and the food passes through the feeding tube and squeezes the inlet. In addition to paste foods, there are "rehydration" foods that can be eaten with water, and "a bite-to-eat" food that can be eaten. According to reports from the astronauts, the texture of paste-like foods is not good; "rehydration" foods are not easy to soften after adding water; foods like toothpaste-like packaging are disgusting; "a bite-eaten" food will spurt many crumbs in the process of eating, not only It can contaminate the surrounding equipment and it may also inhale into the lungs, causing serious consequences.
Later, space foods have been greatly improved, and their varieties and tricks have greatly increased. The astronauts' menu has more than 80 kinds of foods and beverages, including foods such as ham, frankfurter, beef with sauce, chicken nuggets, and sauce. Meatballs, lemon pudding, banana pudding, sugar peaches, assorted jams, peanut butter, beef stew, sausage patty, meat sauce macaroni, bacon applesauce, fruit flavored cereal, corn chips, bacon pieces, chocolate pudding , fruit cakes, small snacks, flavored candy bars, jellies, dried peaches, dried apricots and dried pears, beverages are lemon juice, grape juice, orange juice, apple juice, cherry juice, strawberry juice, black coffee, lemon tea, and instant breakfast and many more.
The Chinese astronauts are also very rich in food. Apart from a wide variety of fish, canned meat, and bread, there are also Chinese dishes such as fish-flavored pork and gongbaoji, which are more delicious than western foods. Dehydrated rice, curry rice and other staples are packed in book-size silver-gray bags. There are a variety of dishes and you can eat seafood such as prawns. As Chinese astronauts love to drink tea, in addition to regular beverages such as orange juice, fashionable modern drinks such as iced tea and green tea are also readily available. Researchers also prepared strawberries, apples, bananas, peaches and other fruits for the astronauts. In order to facilitate preservation, the water was removed at a low temperature and processed into freeze-dried fruits. Although the fruit has become "dried fruit," the taste and color are still good.
3 What are the types of space food?
There are roughly two types of space foods: one is food eaten by astronauts during normal flight in space, and the other is food eaten in special circumstances.
Space foods eaten under normal flight conditions are:
One is ready-to-eat food. It is something that can be eaten without the need for reprocessing, such as a medium-moisture, bite-sized, compression-molded, or coated dry food.
The second is rehydration food. This kind of food is a freeze-dried food, which occupies a large proportion in space food because it is light and small when it is sent to space. However, it must be reconstituted before eating. In its packaging bag, there is a one-way inlet valve for rehydration, and it can be eaten after rehydration.
The third is thermally stable food. Such foods are heat-sterilized soft packs and canned hard-packed foods. It has been proved by space flight that it is perfectly feasible to use plain cutlery to take food from open containers under weightless conditions. This kind of food also accounts for a large proportion of aerospace foods, such as about 80% of food in the Soviet "Salyut 6" space station.
Fourth, frozen and frozen foods. This type of food is brought into space on the ground and it is ready to eat after it is melted.
The fifth is radiation food. It is a radiation-sterilized food that has been used infrequently in the United States space shuttle flight.
Six is ​​a natural food. Such foods are untreated foods on the ground, such as fresh fruits, vegetables, bread, jams and spices.
Seven is a rehydration beverage (ie, granules or soft solid beverages). It needs to be dissolved in space to make cold or hot drinks. On the packaging, the United States used a rehydration beverage bag in the early days, and later switched to a folded plastic bottle and a square refill bag to suck it with a straw.
Special space foods include:
One is spare food. It refers to the foods eaten in the event of an extension of flight in exceptional circumstances, the same type as before.
The second is emergency food. This kind of food refers to the food that the astronauts must wear when wearing a space suit in the event of an aircraft malfunction, such as aluminum tube-packed semi-solid jam, vegetable puree, and meat emulsion. Emergency foods also include when the astronauts landed, they landed far away from human smoke and waited for food during the rescue.
The third is food that needs to be eaten during extravehicular activities. It refers to food stored in a solid or semi-solid, fluid feeder in the collar portion of the helmet for temporary astronauts to drink during long-term extravehicular activities.
4 How to choose space food
The selection of space foods should follow the following basic principles: First, the nutrition structure should be suitable for the nature of the astronauts and the nutrition should be comprehensive. Second, food quality standards are higher than the national standard. In the case of meeting the standards, the key is to ensure the consistency of food quality so as to avoid problems after the astronauts eat. Again, food tastes the same as ordinary people. Finally, the food consumed by the astronauts must be kept for three days in order to track the reactions of the astronauts after eating. In addition, aerospace foods must meet the requirements of astronaut physiological changes under weightless conditions, be able to provide adequate quality protein and calcium and appropriate calcium and phosphorus ratios and vitamin D; fat content of space foods in early flight should not be too high, so as not to aggravate space motion sickness Symptoms; To prevent dysfunction of the cardiovascular system, it is necessary to limit the supply of sodium in aerospace foods and ensure the supply of potassium.
All space foods need to be carefully selected according to these basic principles. If the ground foods meet the standards, they can also be directly adopted or processed into space foods. For example, the main raw material for instant green tea that is consumed by the astronauts after a meal is the National Torch Plan Project, a highly active bifidus factor-promoting intestinal bacteria called stachyose developed by Xi'an Dapeng Biotechnology Co., Ltd. Special nutritional sources. It was adopted after many physical, chemical and microbiological analyses and tastings by astronauts. The most fundamental is that it can assure the astronomers' physical health and increase their physical fitness.
5 Can astronauts drink beer in space?
Astronauts can enjoy a lot of drinks in space, including coffee, cocoa, orange juice, apple juice, cherry juice, grape juice, grapefruit juice and various fruit juice drinks. Chinese astronauts love to drink tea. They also specially prepared iced tea and green tea for them. However, these are rehydration drinks that can only be drunk after adding water. In the space kitchen, 71°C hot water and 10°C cold water are also provided for astronauts to drink.
Although there are plenty of space drinks, there is no beer, which is a pity for foreign astronauts.
To brewing beer in space, you must first solve three problems: First, in the microgravity conditions, wort can not ferment? Second, because there is no buoyancy, the foam will not float to the surface of the beer. How does the beer carbonize? Third, whether or not space beer can produce the right amount of bubbles?