The KH-4 (Keyhole-4) was fourth version in the Corona-program to build an optical reconnaissance satellite. June 2, 1962 at 00:31 UTC · Launch Successful Thor DM-21 Agena-B — United States Air Force, to Low Earth Orbit Space Launch Complex 1W, Vandenberg SFB, CA, USA The world's 171st orbital launch attempt, and 29th of 1962. Data: Launch Library 2, The Space Devs. Image by USAF via The Space Devs.