BEIJING, Oct. 13 (Xinhuanet) -- Oxygen, water and food are three crucial elements to sustain human life. For the two astronauts aboard China's Shenzhou-6 spacecraft, these vital supplies are well guaranteed in space.

　　Fu Lan, former designer of spacecraft environment control and life ensurence for China's manned space project, said that each ofthe two astronauts consumes 0.9 kg of oxygen and exhales around one kg of carbon dioxide each day.

　　Oxygen in a spacecraft is generally kept as highly-condensed gas, liquid gas or in other compounds. Oxygen in Shenzhou-6 is condensed in special steel bottles.

　　An astronaut drinks about 2.5 kg of water every day in orbit. But for long space flight, water recycling and regeneration technology is vital.

　　The two astronauts have three meals a day, 5 to 6 dishes for each meal, including rice, beef balls and dehydrated vegetables. Each day, one astronaut eats 0.6 kg food that produces 2,800 kilocalories.

　　Different from the ground, astronauts in micro-gravity space are more easily to lose appetite and thirstiness. Fu said nutrition experts have been trying to make space food more delicious.