Transit navigation satellite equipped with nuclear power. September 28, 1963 at 20:22 UTC · Launch Successful Thor DM-21 Ablestar — United States Air Force, to Polar Orbit Space Launch Complex 2E, Vandenberg SFB, CA, USA The world's 273rd orbital launch attempt, and 49th of 1963. Data: Launch Library 2, The Space Devs. Image via The Space Devs.