Orbiter - Space Flight Simulator Version:. v. 100830. A free and realistic space flight simulation program for the Windows PC. Slideshow image * Launch the Space Shuttle from Kennedy Space Center and rendezvous with the International Space Station. * Recreate historic flights with addon spacecraft packages: Mercury, Gemini, Apollo, Vostok and more. * Plan interplanetary slingshots and tour the solar system with futuristic space craft. * Design your own rockets, or download addons created by other users. * Learn about the concepts of space flight and orbital mechanics by playing and experimenting.