NASA launched Gemini 12 on Nov. 11, 1966, sending astronauts Jim Lovell and Buzz Aldrin into orbit on the final flight of the Gemini program.
Before NASA could pursue its goal of sending humans to the moon, it needed crews trained in skills such as docking spacecraft in space and performing spacewalks. Earlier Gemini astronauts had difficulty with spacewalks because their spacecraft offered too few handholds, so NASA made changes for this mission. Aldrin conducted three spacewalks, spending more than five hours working outside the spacecraft without major problems.
Gemini 12 also docked successfully with an unpiloted Agena booster that launched the same day. The Agena lifted off just over 90 minutes before Lovell, the mission commander, and Aldrin. After the crew lost radar lock within 74 miles of the vehicle, Aldrin used a sextant to help Lovell rendezvous with the Agena.
During his spacewalks, Aldrin installed handrails and used foot restraints and other tools that have since become routine on orbital spacewalks. The crew also tested tools and techniques that Aldrin and other moonwalkers would later use on the lunar surface. The mission additionally tested a computer-controlled reentry technique when it returned to Earth on Nov. 15, landing Lovell and Aldrin just 3 miles from their target near their recovery ship, the USS Wasp, in the Atlantic Ocean about 600 miles east of Cape Canaveral.
Aldrin, a rookie astronaut and the first to earn a Ph.D., set a precedent by training for his spacewalk in a neutral buoyancy pool in Maryland to better simulate working in weightlessness. He did so again as the second person to walk on the moon on Apollo 11. NASA officials said in a mission overview that the approach became so successful that underwater training has become the primary spacewalk training method used by the United States, Russia and China, and that NASA's Neutral Buoyancy Laboratory in Houston is large enough to include mockups of major sections of the International Space Station, making it the largest indoor body of water in the world with 6.2 million gallons of water.
The astronauts returned to Earth after four days in space, and both men went on to join the Apollo program. Aldrin became the second person to walk on the moon during Apollo 11, and Lovell became the commander of Apollo 13. Gemini 12 closed out NASA's program of two-person space missions, but it established the fundamentals of spacewalking that Apollo astronauts would use when they walked on the moon.
