Kerbal Space Program Xkcd Chart

Players can create rockets, aircraft, spaceplanes, rovers, and other craft from a provided set of components. Once built, the craft can be launched by players from the KSC launch pad or runway, or other launch pads and runways around Kerbin, in an attempt to complete player-set or game-directed missions while avoiding partial or catastrophic failure (such as lack of fuel or structural failure). Players control their spacecraft in three dimensions with little assistance other than a stability system called “SAS” to keep their rocket oriented. Provided it maintains sufficient thrust and fuel, a spacecraft can enter orbit or even travel to other celestial bodies. To visualize vehicle trajectory, the player must switch into map mode; this displays the orbit or trajectory of the player vehicle, as well as the position and trajectory of other spacecraft and planetary bodies. These planets and other vehicles can be targeted to view information needed for rendezvous and docking, such as ascending and descending nodes, target direction, and relative velocity to the target. While in map mode, players can also access maneuver nodes to plan out trajectory changes in advance.