[ODE] Controlling a spaceship

[Darío Mariani]

Hello:
  I'm trying to build a (sort of) spaceship and I'm having trouble
controlling it. I would like to use forces and not to alter the
position, orientation or velocity directly, and make it simple to
maneuver (do not mind if I have to apply a "magic" force).
  I made several tries with no luck, and do not know how to ask it to
"uncle" google (do not find the proper wording).
  A little more info, the ship will be in a more or less stable
situation (a velocity vector and no rotation) and a steering vector
will be given to it (to move to a destination or avoid an obstacle).
  Does anyone have any ideas or have some links that could help me?
  Thanks,

                      Darío