Mercury-Atlas 4 was an uncrewed suborbital test flight of the Mercury program. September 13, 1961 at 14:04 UTC · Launch Successful Atlas LV-3B — National Aeronautics and Space Administration, to Low Earth Orbit Space Launch Complex 14, Cape Canaveral SFS, FL, USA The world's 126th orbital launch attempt, and 33rd of 1961. Program: Mercury Data: Launch Library 2, The Space Devs. Image via The Space Devs.