You have to be weight-conscious - make things as light as possible. If I remember right, it took this much to send a fairly small spacecraft into a free return trajectory: Actually, it was a small craft sent to escape velocity, intended as an entry vehicle for some yet-to-be-added planet. Also, struts are your friend =P I would like to, eventually, make a whole tech tree\'s worth of parts. Higher tech levels would, naturally, make it easier to fly longer distances.