An active repeater communications satellite. The vehicle failed during liftoff. August 18, 1960 at 19:58 UTC · Launch Failure Thor DM-21 Ablestar — United States Air Force, to Low Earth Orbit Space Launch Complex 17B, Cape Canaveral SFS, FL, USA The world's 74th orbital launch attempt, and 20th of 1960. Data: Launch Library 2, The Space Devs. Image via The Space Devs.