John Glenn was not popular with the other astronauts. Glenn was the backup pilot for Shepard and Grissom on the first two manned Project Mercury flights, the sub-orbital missions Mercury-Redstone 3 and Mercury-Redstone 4. Glenn was selected for Mercury-Atlas 6, NASA's first manned orbital flight, with Carpenter as his backup. Putting a man in orbit would achieve one of Project Mercury's most important goals. Shepard and Grissom had named their spacecraft "Freedom 7" and "Liberty Bell 7". The numeral 7 had originally been the production number of Shepard's spacecraft, but had come to represent the Mercury 7. Glenn named his spacecraft, number
Galileo (spacecraft) 1970s the first flybys of Jupiter were achieved by "Pioneer 10" and "Pioneer 11", and before the decade was out it was also visited by the more advanced "Voyager 1" and "Voyager 2" spacecraft. Work on the spacecraft began at Jet Propulsion Laboratory in 1977, while the "Voyager 1" and "2" missions were still being prepared for launch. Early plans called for a launch on on what was then codenamed STS-23 in January 1982, but delays in the development of the Space Shuttle allowed more time for development of the probe. As the shuttle program got underway, "Galileo" was scheduled