Kerbal Space Program is a simulation game in which players build and control their own space-going vessels. From a large array of parts players can build their own rockets and space planes and launch them from a fictional Earth inhabited by Kerbals. In space players can undertake other ventures such as building space stations, space ships or land on other celestial bodies. The game features a realistic physics system and as a result steep learning curve that will test the player's knowledge of physics and will to reach space.
The game features multiple game modes including a career mode in which the player can earn money by going on missions to slowly build up his or her funds for more exciting adventures and researching new technologies. In the sandbox mode the player can build whatever he or she wishes. Science mode allows the player to go on specific missions without having to bother about funds and reputation.