Relay 2, although principally a communications satellite, carried particle experiments designed to map the trapped radiation belt. January 21, 1964 at 21:14 UTC · Launch Successful Thor Delta B — United States Air Force, to Elliptical Orbit Space Launch Complex 17B, Cape Canaveral SFS, FL, USA The world's 296th orbital launch attempt, and 3rd of 1964. Data: Launch Library 2, The Space Devs.