First successfully launched American satellite. It was the first spacecraft to detect the Van Allen Radiation Belt. February 1, 1958 at 03:47 UTC · Launch Successful Juno-I — Army Ballistic Missile Agency, to Low Earth Orbit Launch Complex 26A, Cape Canaveral SFS, FL, USA The world's 4th orbital launch attempt, and 1st of 1958. Data: Launch Library 2, The Space Devs. Image by NASA (NASA Image and Media Guidelines) via The Space Devs.