Do you want to be an astronaut in the future? Every year on April 24, it's Space Day of China. It's a day to celebrate China's 1 in space exploration (探索). Ever since Yang Liwei made 2 to space in 2003, about 20 Chinese astronauts have been to space.
In space, astronauts face many problems. There is 3 gravity (重力). For example, the gravity on the moon is only 1/6 of that on the earth. So their bodies become much lighter in space. 4 , being away from family and friends for a long time can make them feel 5 . What's more, if something goes wrong 6 , they have to work fast and try to fix it by themselves. That's 7 astronauts have to be smart, strong, and ready for any 8 before they can go to space.
To make sure that Chinese astronauts finish their work and 9 to Earth safely, eight kinds of training are set. Apart from (除了) physical training, astronauts also 10 science knowledge and mock (模拟) training. Before they can go to space, they 11 like this for at least three and a half years.
Among the training subjects, the 12 part is the underwater training. It's difficult but helps astronauts 13 the weightless environment in space. Astronauts need to wear diving suits (潜水服) that weigh more than 100 kilos and stay underwater for six hours at a time. Moving around in the water with such a 14 suit is really tiring. One astronaut, Nie Haisheng, even lost 2 kilos 15 one underwater training exercise.
