NASA's First AstronautsApril 9, 1959 - NASA picks its first seven astronauts. They became known as the Mercury Seven. The astronauts were Scott Carpenter, Gordon Cooper, John Glenn, Gus Grissom, Wally Schirra, Alan Shepard, and "Deke" Slayton. All seven would fly in space. • Shepard became the first American in space (1...