6. fuel is needed in space to power certain things like engines.
7. It couldn't, as the lowest speed acceptable to get into space is 7.9 km per second (28,440 km per hour). This is because to break into the barrier that no longer contains oxygen, you would need to be going at an extremely fast rate.
8. It involves Newton's 3rd law. The movement requires that same thrust to be thrown back, also.
9. There is no gravity. So, basically, you just float.