Kerbal Space Program (KSP) is a space flight simulation video game developed by Squad and published by Private Division for Microsoft Windows, macOS, Linux, PlayStation 4, and Xbox One. In the game, players direct a nascent space program, staffed and crewed by green humanoid aliens known as "Kerbals". The game features a realistic orbital physics engine, allowing for various real-life orbital maneuvers such as Hohmann transfer orbits and orbital rendezvous.
The first public version was released digitally on Squad's Kerbal Space Program storefront on 24 June 2011, and joined Steam's early access program on 20 March 2013. The game was released out of beta on 27 April 2015. Kerbal Space Program has support for user-created mods that add new features. Popular mods have received support and inclusion in the game by Squad. People and agencies in the space industry have taken an interest in the game, including NASA, the European Space Agency, and Peter Beck, CEO and CTO of Rocket Lab.In May 2017, Squad announced that the game was purchased by video game company Take-Two Interactive, who will help support Squad in keeping the console versions up-to-date alongside the personal computer versions. An Enhanced Edition was released on the Xbox One and PlayStation 4 in January 2018, and set to be release in 2021 for PlayStation 5 and Xbox Series X/S by Private Division, a publishing subsidiary of Take-Two Interactive. Two expansions for the game have been released as downloadable content: Making History in March 2018 and Breaking Ground in May 2019. A sequel, Kerbal Space Program 2, has been announced for a 2022 release.