Astronauts do live in the International Space Station while working on space but eventually those astronauts do return to earth after completing their work and mission in space.
The International Space Station allows the Astronauts and people in them to survive while in space and have a place to poop and pee etc.
The International Space Station crew lives and works on the International Space Station while it's traveling at a speed of around 5 miles per second which is pretty fast.
Amazingly the living and working space in the International Space Station is even larger than a six bedroom house and has six sleeping quarters, two bathrooms, a gym, and a 360-degree view bay window.
So the astronauts in the ISS are pretty comfortable while up there in space.