An Explorer satellite atop a Jupiter-Redstone rocket.
Work on Redstone led to advanced variants like the Jupiter-A and C, as well as a 12,000-pound Jupiter-class booster rocket built exclusively for space research, rather than missile use. It was tentatively called Juno. Juno’s many claims to fame include the launching of America’s first satellite, Explorer I, on 31 January 1958. NASA also used Juno to launch Pioneer IV, which brushed past the Moon in March 1959 before entering permanent solar orbit. In that same year a Juno II rocket carried Explorer VII—a satellite packed with advanced instruments for monitoring micro-meteors and solar radiation—into space. It transmitted data continuously for two years.
In 1958, the Army’s Project Adam planned to launch a man just below low earth orbit to an altitude of 150 miles aboard a modified Juno rocket before splashing down in the Atlantic Ocean. Some experts ridiculed the plan as “shooting the lady out of a cannon” and it was ultimately shelved. When Redstone and Juno/Jupiter assets were transferred to NASA, however, Project Adam morphed into Project Mercury and made history after successfully launching the first Americans into space.