Space Walk description

The game simulates space walk.
In the game you play as a astronaut, who has lost in the space. Rocks are coming to you again and again. You need to control your space suit to avoid the rocks, in order to keep you alive as long as possible.
There are 3 operations to control the space suit:
Accelerate: usually this means go straight, but when you are moving or turning, it isn't. You need to composite the current velocity with a new linear velocity towards the astronaut's head.
Turn clockwise: this make the astronaut rotate to the clockwise direction, and it also give an vertical velocity.
Turn counterclockwise: opposite to turn clockwise.
The game is built on a physics engine. The gravity is set to zero, so that to make it like the situation in space. A little physics might help playing the game.