Is it possible to turn your spaceship around in space, or can you only turn but keep going forward?

If you mean can you turn the ship around and then start going in another direction (opposite or even different) the answer is - yes you can do it, but you can't do it instantaneously, and really whether or not you could do it would depend on how much energy you had available to do what you want to do.

This is very much like a car going down the freeway. You can change the direction by turning the steering wheel, but if you managed to turn the car around 180 degrees to face the direction you came (without wrecking!), you would continue to go in the direction you were traveling before you turned (you would now seem to be going backward) until you applied enough engine power to kill your first velocity and change it to the new direction.

This is directly related to Newton's first law of gravitation (Inertia). It basically states that an object in motion tends to remain in motion (in the same direction and speed) until a force is applied to change it.

In the case of a rocket ship (using Newton's third law - any reaction produces an equally strong, and oposite reaction, which is why a rocket works in space without anything to "push" against), it would be impossible to just "turn around" and go in the opposite direction because the amount of energy involved at the speeds a spaceship would be traveling would be so great that the ship could not carry enough fuel to change the speed sufficiently.

You would need a spaceship that has an "inertialess" drive to function. Basically that means that it would have to have some way to cancel the force that had been built up accelerating to move it in another direction. Unfortunately, there is no such thing as an inertialess drive (at least, with our current understanding and physics such a thing is impossible).

You can turn around quite easily. However, unless you apply thrust, the spaceship will continue in its original direction and speed (except that you will now be looking backwards -- a bit like a car on ice that gets spun around).

In fact, one cheap way to change course is to turn the space craft sideways and blast the rocket just long enough to change the course by the required amount of degrees. At no time during the process is the spacecraft actually facing the way it is going.

http://www.space-shuttle-mission.com/forum/index.p...

Yes, space shuttle, with it's OMS control systems, can do more than just turning around.