The DSAP-1 (Defense Satellite Application Program Block 1) satellites series, also known as P-35, was the first series of military meteorologal satellites of the USA. June 18, 1964 at 04:56 UTC · Launch Successful Thor SLV-2 Agena D — United States Air Force, to Sun-Synchronous Orbit Space Launch Complex 1W, Vandenberg SFB, CA, USA The world's 331st orbital launch attempt, and 38th of 1964. Data: Launch Library 2, The Space Devs. Image by USAF via The Space Devs.