The Minotaur I, or just Minotaur is an American expendable launch system derived from the Minuteman II missile. It is used to launch small satellites for the US Government, and is a member of the Minotaur family of rockets produced by Orbital Sciences Corporation.Minotaur I rockets consist of the M55A1 first stage and SR19 second stage of a decommissioned Minuteman missile. The Orion 50XL and Orion 38, from the Pegasus rocket, are used as third and fourth stages.