afaik, any VTOL with thruster attached can enter space.
You can depart from anywhere on the planet. Special keys? Not really. Simply use the "move up" hotkey you probably already have for the VTOL, and keep going up until you get the message that you are about to enter space (iirc, around 900m elevation)
Once in space, it takes a while to get used to the difference in flying. R still works, or the forward/back arrows. The difference is that your "turn left" and "turn right" actually rotate the ship on it's center axis. Maybe I am explaining this badly, but try it as soon as you get into space. You will see what I mean. Oh, and when you leave the planet, you arrive at space station, so you are in a safe zone.
Actual turning, going "up" and "down" are controlled by the mouse. The front of the ship will move in the direction of mouse movement.