When astronauts sleep in space, they are zipped into sleeping bags which are then attached to the walls of their spacecraft. This keeps them from floating around in their sleep.
Space stations are large orbiting satellites that stay in space for years at a time.
Crews of astronauts take turns living and working in them. They usually stay for several weeks or months. Some have stayed for as long as a year. Skylab was designed to be a laboratory for astronauts and an airport for spacecraft. Three different crews of astronauts spent a total of more than 3,000 hours doing experiments while aboard Skylab .