How the scientist of space stay at space?
They stay in something called a- 'Low Earth Orbit'. This is a space between earth and outer space.
There isn't enough Gravity for them to be pulled to earth, and not enough to be pulled our to space so they stay orbiting arounf the Earth. In a Shuttle obvcourse.
The International Space Station was assembled in space and is designed to stay there. It is meant as a place of research and as a place for astronauts to stay in space. A space shuttle is a vehicle that can lauch from Earth into space and then return, something a space station cannot do. Space shuttles transport people and equipment to and from space.