The KH-4 (Keyhole-4) was fourth version in the Corona-program to build an optical reconnaissance satellite. KH-4 13 carried the RM 4 radiometer payload (identical to RM 3) for background measurements for the MIDAS program. September 29, 1962 at 23:34 UTC · Launch Successful Thor Agena D — United States Air Force, to Low Earth Orbit Space Launch Complex 2W, Vandenberg SFB, CA, USA The world's 200th orbital launch attempt, and 58th of 1962. Data: Launch Library 2, The Space Devs. Image by USAF via The Space Devs.