Hi! Yes, those keys definitely angle your ship. This affects everything. The game is fully 3d, and your gun always faces forward. If you angle up or down, the projectiles will also move in the exact direction you're facing. So if you face too high or too low, your projectiles will either fly over, or under, the satellite you're aiming for. This is also the case for picking up debris. If you're not aiming for it, you will pass over or under it and not pick it up. You have to make sure that you keep adjusting your pitch angle to point directly at either the debris or the satellite.
Hope that helps a bit.