Explorer 15 was instrumented to study the artificial radiation belt produced by the Starfish high-altitude nuclear burst of July 1962. The backup payload for Explorer 14 was modified and used for Explorer 15. October 27, 1962 at 23:15 UTC · Launch Successful Thor Delta A — United States Air Force, to Elliptical Orbit Space Launch Complex 17B, Cape Canaveral SFS, FL, USA The world's 210th orbital launch attempt, and 68th of 1962. Data: Launch Library 2, The Space Devs.