March 23, 1965 marks the launch of the first manned Gemini rocket. The Gemini III spacecraft, nicknamed Molly Brown, was flown by Gus Grissom, command pilot, and John W. Young, pilot. They orbited the Earth three times. The flight demonstrated that the astronauts could change orbit, remain in space for at least two weeks, and work outside the spacecraft. They also pioneered techniques to rendezvous and dock with another spacecraft, a requirement for the successful Apollo missions to come.

Grissom was on his second flight, the first man to travel to space twice. Grissom died along with astronauts Ed White and Roger Chaffee in a fire during a pre-launch test of Apollo 1 in 1967. Young would become NASA's longest serving astronaut, flying the command module for Apollo 10 and walking on the moon during the Apollo 16 mission. He was chosen as commander of the first Space Shuttle mission, STS-1, in 1981. (NASA)

Gus Grissom and Robert Young train for the Gemini III mission.