The test engine developed for NASA's X-33 spacecraft, a small-scale prototype of a proposed reusable launch vehicle (RLV) that was to replace the space shuttle. The X-33, however, was cancelled in 2001. The Aerospike engine had a variable nozzle system to compensate for different altitudes. Rocketdyne Propulsion and Power, part of the Boeing Company, developed and assembled it.
Subjects: Astronomy and Astrophysics.