ORBITER is an extremely sophisticated and realistic non-commercial space flight simulator. It does for space what Microsoft Flight Simulator does for air and Microsoft Train Simulator does for rails. It excels even in its basic "out of the box" form, but what make it really superior are the wide variety of custom addons. Realistic and futuristic spacecrafts, rockets, flight instruments, autopilots… Orbiter provides excellent documentation and programming API for developing your own addons!
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