An ejection seat is a system used to rescue the pilot of an airplane in an emergency. Usually, the seat is propelled from the plane by explosives or rockets. Once off the plane, the ejection seat's descend is controlled by using a parachute. Here is a video showing an ejection seat test mission conducted by the USAF. There are very few missions requiring years of planning and preparation, only to be accomplished in less than six seconds. There are even fewer facilities where such a mission can take place. The Holloman High Speed Test Track (HHSTT) is a facility that enables test scientists and engineers to meet both of the above criteria. Tests on the track provide data on problems that cannot be solved by other ground test means. The tests are conducted by securing the ejection seat to a rocket-propelled sled and launching the sled to a speed identical to that of which a pilot will encounter in an actual flight.