In the late 1950s, the U.S. Air Force started a series of advanced strategic missile projects under the designation Weapon System WS-199A. One of the projects studied under the 199A umbrella was Martin's "Bold Orion" air-launched ballistic missile (ALBM) for the B-47 Stratojet, based on the rocket motor from the Sergeant missile. Twelve test launches were carried out between 26 May 1958 and 13 October 1959, but these were generally unsuccessful and further work as an ALBM ended. The system was then modified with the addition of an Altair upper stage to create an anti-satellite weapon with a range. Only one test flight of the anti-satellite mission was carried out, making a mock attack on the Explorer 6 at an altitude of . To record its flight path, the "Bold Orion" transmitted telemetry to the ground, ejected flares to aid visual tracking, and was continuously tracked by radar. The missile successfully passed within of the satellite, which would be suitable for use with a nuclear weapon, but useless for conventional warheads.