Jupiter-C carried the first successful American artificial earth satellite, Explorer 1, into orbit on January 31, 1958. Jupiter-C launched additional Explorer satellites on March 26 and July 26, 1958.

Jupiter-C, or Juno 1, is a modified version of the Redstone Ballistic Missile and a direct descendant of the V-2 (A-4) rocket developed in Germany during the second World War.

The vehicle’s main stage is powered by a rocket engine burning liquid oxygen and a hydrazine mixture. The second and third stages are contained in the “tub” on the nose of the rocket. Both use scaled-down Sergeant solid-propellant rockets: eleven in the second stage and three in the third. A final Sergeant motor is attached to the base of the satellite to provide the velocity necessary to place the vehicle in orbit. An electric motor spun the entire “tub” prior to launch and during the climb into space in order to stabilize the satellite.

The Jupiter-C was built by the U.S. Army Ballistic Missile Agency.