[Illustration: 67. Jupiter-C launches the first American satellite,
January 31, 1958.]
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.