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
John Glenn who had been shot at by a MiG could sit while those who had not had to stand. Glenn later wrote, "Since the days of the Lafayette Escadrille during World War I, pilots have viewed air-to-air combat as the ultimate test not only of their machines but of their own personal determination and flying skills. I was no exception." He hoped to become the second Marine jet flying ace after John F. Bolt. When Glenn complained about there not being any MiGs to shoot at, his USAF squadron mates painted "MiG Mad Marine" on his aircraft. He shot down his