What's a spacewalk? Any time an astronaut gets out of a spacecraft(航天器) while in space, it is called a spacewalk. Astronautsgo on spacewalks for many reasons. For example, experiments can be placed on theoutside of a spacecraft. This lets scientists learn how being in space affects(影响) different things. By going on spacewalks, astronauts can also fix thingsinstead of bringing them back to the earth to fix.
When astronautsgo on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits,astronauts have the oxygen(氧气) they needto breathe and the water they need to drink. To keep the astronauts and the spacecraftsafe, the astronauts must leave and go back to the spacecraft through a specialdoor. When on a spacewalk, astronauts use safety tethers to stay close to theirspacecraft. Tethers are like ropes, connect the spacewalkers with the spacecraft.They keep astronauts from floating(漂 浮) away into space.Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFERis worn like a backpack. It helps an astronaut move around in space.
How doastronauts train for spacewalks? One way is by going for a swim. Floating in spaceis a lot like floating in water. Astronauts practice spacewalks underwater in ahuge special swimming pool. For every one hour they will spend on a spacewalk, astronautsneed to train seven hours in the pool. Another way astronauts practice for a spacewalkis by using virtual reality(虚拟现实). It looksand feels just like a spacewalk.
Today,only three countries have finished spacewalks independently. They are Russia, theUnited States and China. The first person to go on a spacewalk in the world wasAlexei Leonov from Russia. Zhai Zhigang is the first Chinese astronaut to go ona spacewalk. The world record of spacewalks is held by Russian astronaut AnatolySolovyev. He has been on 16 spacewalks and spent more than 82 hours outside in space.
