How do you sleep in space?
Astronauts sleep in sleeping bags. Most astronauts have a small sleep station that includes room for some personal items and a computer. The sleeping bag is attached to a wall to prevent them floating around.
Sleeping areas must have a constant airflow, otherwise the astronauts end up in a bubble of their own exhaled CO2.
In the photo above, notice how the astronaut's arms float in front of him as he sleeps.