The Minotaur IV HAPS launch system is derived from the Peacekeeper ICBM. The first three stages are taken directly from decommissioned Peacekeeper missiles. A fourth stage, the Orion-38, is taken from the Pegasus family of air-launched rockets. A fifth stage, consisting of a hydrazine-powered motor called HAPS, increases orbital insertion accuracy and allows additional orbital maneuvering.