Kerbal Space Program (KSP) is a spacecraft simulation game for Mac, Linux or Windows. Players build, launch, and pilot spacecraft and airplanes through a fictional 8 planet star system.
Kerbal Space Program (KSP) is a sandbox spacecraft simulation game where players build, launch, and control spacecraft and aircraft, and manage a space program as a whole.
There are three game modes to play in: sandbox, science and career. In the sandbox mode, all parts are unlocked from the start and there is no cost to build rockets or planes, allowing for player experimentation. In the science mode, parts are unlocked through a tech tree with science points, which can be earned through performing experiments and taking crew reports. In both cases, overall goals are player defined, and could include such activities as landing a Kerbonaut on the Mun and returning him safely to Kerbin, or exploring the other planets in the star system the Kerbals call home. The third mode, career mode, adds contracts, funds (in-game currency) and reputation. Contracts can be simple, like testing a rocket part (although often under strict conditions), or gathering specific science at specific locations, or more complex, like building space stations in orbit, outposts on planets or moons, or recovering stranded Kerbals. You can gain funds and reputation by completing contracts, and sometimes even science points.
KSP is developed by Squad, and used the early access sales model prior to the full 1.0 release on April 27, 2015, with post release development for features and bug fixes ongoing. The current version is available for purchase on their website or Steam platform, while an older version is available as a demo containing limited parts and celestial objects.
KSP also has an active modding community who develop new parts and plugins, and can be found on the official forums, on Curse, and other unofficial community sites. An officially hosted community wiki is extremely resourceful for new and experienced players alike.