Originally Posted by LuceBianchi
A ship in space would need fuel to start moving, to stop moving, and to change course, (as well as support life) but not to *continue* moving, or stay in space (except for unstable orbits, as mentioned above). (Except for FTL travel. *Something* has to bend physics to your will, dammit.)
A ship in space needs power to keep the air blowers working, otherwise people would smother in their own carbon dioxide, or they'd have to keep moving around and waving their arms to keep the gases mixed. Also, for air recycling, water recycling, etc.