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. March 18, 1965 at 04:43 UTC · Launch Successful Thor MG-18 — United States Air Force, to Sun-Synchronous Orbit Space Launch Complex 10W, Vandenberg SFB, CA, USA The world's 418th orbital launch attempt, and 25th of 1965. Data: Launch Library 2, The Space Devs.