Left/Right arrows - move around asteroid, rotate while flying.
Up arrow - hold it to prepare jump and control its power. Release to jump. Activate jetpack while flying.
All these actions are available for WSAD and Mouse.
Escape - cancel jump, when you holding Up button, otherwise go to main menu.
If you want to overview the level, move your mouse cursor over the screen border and scroll it in any direction.
See the Game Guide