Buzz Aldrin will always be remembered as one of the first two humans to walk on the Moon during Project Apollo. In the public eye, that achievement has eclipsed his important contributions to the earlier Project Gemini. Two key goals of that program, which launched 10 two-astronaut crews in 1965 and 1966, were to perfect rendezvous and docking and learn how to work outside the spacecraft. Both were essential to the lunar landing goals of Project Apollo. Aldrin, an Air Force pilot who finished a Ph.D. on orbital rendezvous theory before he became an astronaut in 1963, played a central role in preparing the techniques for meeting up with another spacecraft. More accidentally, he also became the first astronaut to demonstrate how useful work could be done during a zero-gravity spacewalk. On Gemini XII, the very last flight in the program, he showed that, with proper handholds, footholds, and rest periods, it was possible to do something useful. This success came after astronauts on the three previous missions had problems accomplishing their tasks, in two cases becoming dangerously overheated and exhausted. Demonstrating that someone could work in a spacesuit was the one thing that needed to be accomplished before Gemini wrapped up. 

Aldrin’s presence on XII was the product of a tragic accident. In early 1966, the prime crew for Gemini IX was killed in a crash of their T-38 jet. Their backups, Thomas Stafford and Eugene Cernan, took over the mission. Their new backup crew became James Lovell and Edwin E. Aldrin Jr. (Buzz officially adopted his nickname as his legal name in 1988). Lovell and Aldrin had originally been named the backups for Gemini X, which under the usual rotation after three missions would have made them the crew of XIII—except there was no XIII. The program was capped at 12 flights. As Aldrin was acutely aware, he would not have flown in Gemini without the loss of his compatriots. And if he hadn’t, it was unlikely that he would have been on the prime crew of an early Apollo mission, and thus would not have been on the first lunar landing.

Being the backup to Gene Cernan on Gemini IX, and thus potentially filling the right-hand seat on XII, put Buzz Aldrin in the middle of training for extravehicular activity (EVA)—NASA jargon for walking in space. Cernan had an ambitious objective on IX: float into the back of the Gemini spacecraft and strap on a U.S. Air Force jetpack called the Astronaut Maneuvering Unit (AMU) and fly around. But when he finally got to make that walk on June 5, 1966, it was a disaster. Cernan found that laws of physics in weightlessness caught up with him. Without proper handholds or footholds, he thrashed around trying to do any real work. Moreover, the Gemini spacesuit, which only cooled the body through the circulation of oxygen, was overwhelmed. Cernan’s visor fogged over from his sweating and he was forced to make an emergency return to the cabin.  

Cernan’s failed EVA forced NASA’s Houston center to come to grips with its inadequate spacewalk experience and training. The only previous EVA, Edward White’s on Gemini IV in June 1965, featured little real work and was fun. The emergency landing of Gemini VIII in March 1966 prevented David Scott from taking his EVA, which would have demonstrated that spacewalking was actually difficult. As I have written elsewhere, the primary answer came from a small contract for NASA Langley Research Center. Environmental Research Associates, a tiny company run by two partners, was experimenting with underwater training in a school pool outside Baltimore. Cernan went there in July and tried to don a model AMU in a Gemini adapter mockup. He was relieved to find that floating in “neutral buoyancy” demonstrated that many of his problems working in weightlessness were created by the medium and his inadequate equipment, as some were questioning whether the failure was just his fault. 

The Gemini program was on a hectic schedule of a launch every other month, so neither Michael Collins on Gemini X nor Richard Gordon on Gemini XI had time to incorporate underwater training for EVA. As a result, they both had difficulties, especially Gordon, who had more ambitious tasks to accomplish. He struggled to attach a tether between the Gemini XI spacecraft and the Agena rocket stage it had docked with, becoming so exhausted that he, like Cernan, had to abandon the rest of his EVA objectives. As a result, only Aldrin, who had witnessed Cernan’s pool experiments, had the time to go back to Baltimore for training and work through the procedures and equipment developed in the pool.  

Aldrin’s primary EVA objective was to repeat the AMU experiment, this time with footholds and handholds that might make donning feasible. In the school pool in Owings Mills, Maryland, Aldrin trained in September 1966 to do just that. But much to his chagrin, and that of the Air Force, NASA management canceled the AMU on Gemini XII, concerned that it was too complicated and problematic. The primary objective had to be demonstrating that work in zero-G was feasible at all before the Gemini program was over. Aldrin was instead given tasks like turning a bolt, plugging-in electrical connectors, and operating a power tool. When he returned to the pool in October, he felt that his objectives were so simple that the monkey he’d given his wife as a pet could have done them. When he was underwater one day, he let out a loud screech over the radio. When Cernan (now his backup) and the safety divers reacted with surprise, he said, “Shut up and pass me a banana.” After that, parties unknown left a constant supply of bananas in Aldrin’s Houston office.  

Buzz Aldrin and Jim Lovell finally launched on Gemini XII on the afternoon of Veteran’s Day, November 11, 1966. They immediately set about chasing the Agena target vehicle that had ascended from a nearby Cape Canaveral launch pad 90 minutes earlier. But Gemini XII’s radar could not hold a stable lock on the Agena’s transponder. Buzz, who also had the nickname “Dr. Rendezvous,” was able to demonstrate his skill with the manual backup method he had helped develop. He used a sextant to take optical sightings and employed charts to calculate the numbers to put in the computer. Lovell then knew when to fire the thrusters. The rendezvous and docking went smoothly.  

On the second day in orbit, Aldrin did a “standup” EVA, floating in the hatch opening and doing scientific experiments such as astronomical photography with an ultraviolet camera. It was a technique first tried on Gemini X and XI. That was easy. Day 3 had the real test. First, he attached a movie camera to the Gemini spacecraft, pulling himself hand-over-hand to the spacecraft's nose on a handrail added for the purpose. He used a short tether attached to his waist to restrain himself as he hooked a big tether between the spacecraft and the Agena. Unlike Gordon’s experience trying to wrap his legs around the Gemini’s nose to stay in place, Aldrin had no trouble. Then he moved to the back of the Gemini spacecraft to work on his “busy box” of tasks. Two “golden slippers”—yellow, overshoe-like foot restraints—stabilized his position. He experimented with one or two waist tethers, worked with bolts and washers, and used a tool to cut metal. Then he moved back to the Agena, where he worked another “busy box” with electrical connectors and experimented with a power screwdriver. He took prescribed rest periods between tasks. Buzz was back in his seat after 2 hours and 20 minutes without incident. The next day he did another standup EVA.

Aldrin certainly did not solve the problem of doing useful work in weightlessness by himself. Without the pioneering work in neutral buoyancy training in a school pool outside Baltimore, he and NASA would not have had the tools to do so. But he was the one who helped refine the tools and techniques and then actually demonstrated them in space. Project Gemini was able to end with that last box checked, and he, along with Lovell and Cernan and other Gemini astronauts, went to the Moon early in Apollo.

Michael J. Neufeld is the Museum’s curator for Mercury and Gemini spacecraft and for rockets and missiles up to 1945.