Kerbal Space Program is a space flight simulation and engineering sandbox where players design, build, and launch rockets crewed by the accident-prone green Kerbals. Getting anything off the ground means grappling with real orbital mechanics, aerodynamics, and rocket science basics.

Missions range from simple test flights to full interplanetary expeditions, and much of the appeal comes from watching carefully engineered creations succeed spectacularly or fail even more spectacularly.