The International Space Station

This month, astronauts are celebrating 20 years of living in space. People have been living on the International Space Station since 2000 - but how do they do it? And what do they do there? Briefing Questions What is the International Space Station? The first people to go into space only went up for short trips to see what it was like. Today, they can spend months living and working in space. They stay on a large spacecraft that orbitsThe curved path of an object around a sun, star or planet. Earth. The International Space Station, known as the ISS, was built by lots of different countries, and astronauts from all over the world have lived there. This Friday (20 November) marks 20 years of humans living in space. How do you become a crew member? Before each mission, astronauts train for being in space. They spend hours learning in a classroom as well as handling space equipment. Because astronauts feel weightless on board the ISS, they have to prepare for the sensation. For this, they use a huge water tank. Wearing modifiedTo modify is to change or alter something in some way. spacesuits, astronauts work with life-sized models of the ISS. What do the astronauts do once they arrive? Living on the ISS means working as part of a close team. The astronauts on board are all scientists who spend their days carrying out experiments. They grow plants and check how life in zero gravityThe feeling of weightlessness. This happens when there is no gravity – the force we feel on Earth that pulls us towards the centre of the planet. affects the human body. Another important part of their job is to make sure the Space Station is in perfect working order. Sometimes, there are problems outside, so they go on spacewalksWhen an astronaut moves about outside a spacecraft in outer space. to do the repairs. Is normal life difficult? Eating and sleeping may be normal activities on Earth, but in space they become much more complicated. In space, objects are weightless - even people! Astronauts have sleeping bags attached to the walls so they don't float away while in bed. Meals are different, too. They come in special packages with straws that astronauts suck to eat or drink. The water is recycled from the astronauts' breath, but all food is sent from Earth. In 2001, a pizza company even "delivered" a pizza in a rocket. How does living in space affect people's bodies? Most astronauts experience space sickness soon after arriving. Body fluids rise to the head, giving people a cold, stuffy nose and a puffy face. The lack of gravity also means that the body does not have to work very hard. Astronauts have to exercise to stop their muscles getting too weak. They have specially made treadmills and weights that work in zero gravity. What else is different? Living on the space station has lots of mental challenges. Crew members are on board for long periods of time - at least six months. Even though the astronauts can spend time with each other, they miss their friends and families. Many of them also say they miss weather, like wind and rain. By making notes about how they feel living in space, the crew can prepare for future trips when astronauts travel much further away - for example to the Moon or Mars.KeywordsOrbits - The curved path of an object around a sun, star or planet.