An American satellite in order to study the Van Allen radiation belts and the effects of nuclear explosions upon these belts. July 26, 1958 at 15:00 UTC · Launch Successful Juno-I — Army Ballistic Missile Agency, to Medium Earth Orbit Launch Complex 5, Cape Canaveral SFS, FL, USA The world's 15th orbital launch attempt, and 12th of 1958. Data: Launch Library 2, The Space Devs. Image by NASA (NASA Image and Media Guidelines) via The Space Devs.