The North American Aviation AGM-28 Hound Dog was a supersonic, jet propelled, air-launched cruise missile. The Hound Dog missile was first given the designation B-77, then redesignated GAM-77, and finally as AGM-28. The Hound Dog was conceived as a temporary stand-off weapon for the B-52 Stratofortress bomber, to be used until the GAM-87 Skybolt air-launched ballistic missile was available. Instead, the Skybolt missile was cancelled within a few years, and the Hound Dog was deployed for 15 years until the missile was replaced by newer weapons, including the SRAM missile and the AGM-86 Air-Launched Cruise Missile.