Triumph of the Mark One Cranium Computer: The Flight of Gemini XII (Part 1)

The nose of Gemini XII and the grandeur of Earth, as captured by Buzz Aldrin during one of his sessions of EVA. Photo Credit: NASA

The nose of Gemini XII and the grandeur of Earth, as captured by Buzz Aldrin during one of his sessions of EVA. Photo Credit: NASA

Not long after his return from the Gemini IX-A mission, astronaut Gene Cernan was summoned to Deke Slayton’s office and was asked an unusual question.

“Geno, how soon can you be ready to fly again?”

“Just say the word, Deke. When?”

“Right now. Would you be willing to jump from backup to prime? Fly [Gemini] XII with Lovell?”

The year 1966 had certainly been a dramatic one for Cernan. When it began, he and Tom Stafford confidently looked forward to flying Gemini XII—the last mission in the series—themselves. Then, with awful suddenness, the deaths of Elliot See and Charlie Bassett in February pushed them from backup to prime crew on Gemini IX. Following his return from his first spaceflight, Cernan had been given a “dead-end” assignment, with Gordon Cooper, to back up Jim Lovell and Edwin “Buzz” Aldrin on Gemini XII. Now, Slayton was offering to break his own crew-rotation system, bumping Aldrin from the mission. Cernan’s first question to Slayton was a simple one. Why?

The reason was the Astronaut Maneuvering Unit (AMU)—a U.S. Air Force-built rocket armchair which Cernan was originally supposed to test on Gemini IX-A in June 1966—whose military sponsors were pushing strongly to fly again on Gemini XII. Without giving much away, Slayton told Cernan simply that he was the best man to fly the AMU, which was probably true, but a number of contributory factors centered on Buzz Aldrin himself: a man of mathematical and engineering genius, the first astronaut to possess a doctorate, an unquestioned expert in the field of space rendezvous … and a constant worry to Slayton. Aldrin had already raised some eyebrows during his stint as Gemini IX-A’s backup pilot, when he made suggestions during Cernan’s EVA which were considered a little too adventurous in light of NASA’s limited experience.

In his autobiography, The Last Man on the Moon, Cernan hinted that Aldrin’s intelligence was tempered by a tendency to fly off at tangents and want to drastically re-engineer everything, at a time when NASA had little time to do so. Coupled with reports of his performance in the Gemini simulators, it was Slayton’s judgment that the AMU test flight should be entrusted to Cernan, rather than Aldrin. In his defense, Aldrin would blame the decision on problems experienced by both Cernan and Gemini XI’s Dick Gordon on their EVAs: exhaustion, fogged-up visors, and difficulty in performing even simple tasks. “An urgent meeting of senior officials concerned with the Gemini XII EVA,” Aldrin wrote in his memoir, Men from Earth, “was held at the end of September and … they decided arbitrarily that I stood a poor chance of putting the innovative AMU backpack to good use. They felt the risks outweighed the benefits.” For his part, Cernan accepted Slayton’s invitation and would have flown Gemini XII had not the decision been made that an AMU test was too risky. Gemini XII’s EVAs would focus instead on less dramatic evaluations of a spacewalker’s performance outside the pressurized confines of his spacecraft.

Gemini XII prime crewmen Jim Lovell (front right) and Buzz Aldrin (front left) were assigned the task of closing out Project Gemini. Behind them are backup crewmen Gene Cernan (left) and Gordon Cooper. Had it not been for the decision not to refly the risky Astronaut Maneuvering Unit (AMU), it is possible that Cernan may have flown Gemini XII in Aldrin's stead. Photo Credit: NASA

Gemini XII prime crewmen Jim Lovell (front right) and Buzz Aldrin (front left) were assigned the task of closing out Project Gemini. Behind them are backup crewmen Gene Cernan (left) and Gordon Cooper. Had it not been for the decision not to refly the risky Astronaut Maneuvering Unit (AMU), it is possible that Cernan may have flown Gemini XII in Aldrin’s stead. Photo Credit: NASA

After his selection into NASA’s third group of astronauts in October 1963, Aldrin focused initially on mission planning and was dismayed by his lengthy wait for a flight assignment. In early 1966, he and Jim Lovell were assigned as the backup crew for Gemini X … a dead-end assignment which, taking into account Slayton’s three-flight rotation policy, would have positioned them for the prime crew slot on Gemini XIII.

Unfortunately for them, Project Gemini was planned to end with Gemini XII. …

All that changed on the last day of February 1966, when Gemini IX crewmen Elliot See and Charlie Bassett were killed and their backups—Tom Stafford and Gene Cernan—were pushed into prime position. In mid-March, Lovell and Aldrin were named as the new Gemini IX backups, with a formally-unannounced (but anticipated) future assignment as the prime Gemini XII crew. For Aldrin, whose Nassau Bay backyard bordered that of the Bassett’s, it was a devastating way to receive a flight assignment. Three weeks after the accident, he and his wife, Joan, visited Jeannie Bassett to tell her the news. “I felt terrible,” he wrote, “as if I had somehow robbed Charlie Bassett of an honor he deserved.” Jeannie responded with quiet dignity and characteristic grace: her husband, she explained, felt that Aldrin “should have been on that flight all along … I know he’d be pleased.”

As the Gemini XII flight hardware was readied for launch, it was accompanied by a deadline to end the program and press on with Project Apollo, whose end goal was the first piloted landing on the Moon. Indeed, when Lovell and Aldrin walked out to Cape Kennedy’s Pad 19 on launch morning, 11 November 1966, they wore placards reading “The” and “End” on their backs. In addition to rendezvous and docking with an automated Agena target vehicle, Aldrin would perform EVAs to perfect the basics of spacewalking: removing, installing, and tightening bolts, operating connectors and hooks, stripping patches of Velcro, and cutting cables. To physically condition themselves, Aldrin and Cernan spent a considerable amount of time underwater in the neutral buoyancy tank. They wore ballasted suits, Aldrin said later, to completely neutralize their buoyancy and approximate microgravity as closely as possible. “Eventually,” he wrote in Men from Earth, “I mastered the intricate ballet of weightlessness. Your body simply had to be anchored, because if it wasn’t, flexing your pinkie would send you ass-over-teakettle. And you don’t want to do that dangling at the end of an umbilical cord 160 miles above Earth.”

With a recognized background in orbital rendezvous mechanics, Buzz Aldrin's work was instrumental in the successful docking between Gemini XII and its Agena target. He also participated in several periods of EVA. Photo Credit: NASA

With a recognized background in orbital rendezvous mechanics, Buzz Aldrin’s work was instrumental in the successful docking between Gemini XII and its Agena target. He also participated in several periods of EVA. Photo Credit: NASA

Plans to launch on 9 November were abandoned when a malfunctioning power supply in the Titan II rocket’s secondary autopilot reared its head, and Lovell and Aldrin were recycled to fly two days later. The morning of the 11th dawned fine and clear, and the Agena and its Atlas launch vehicle set off promptly from the Cape’s Pad 14 at 2:08 p.m. EST. During insertion into space, an anomaly was noted in the target’s propulsion system and plans to boost Gemini XII into a higher orbit were abandoned. Strapped inside their tiny cabin, both astronauts could clearly hear the Atlas’ thunderous roar. At 3:46:33 p.m., it was their turn. “There was no noise at first,” Aldrin wrote, “but then a growing rumble began as the spacecraft rolled through its pre-programmed maneuver, twisting to the proper south-east launch trajectory.” Steadily, the Titan II accelerated, “like a subway train,” Aldrin recalled, and as they climbed ever higher the sky steadily darkened to pitch black. Inside their suits both men felt their limbs rise and their toes lift to touch the tops of their boots. It felt almost as if they were stretching their feet, but not quite. They were weightless.

Once established in their 100 x 170 mile (160 x 270 km) orbit, Lovell and Aldrin set to work on their checklists, preparing for rendezvous and docking with the Agena some three orbits—and a little over four hours—into the mission. At around 5:11 p.m. they made their first attempt at radar contact with the target and were surprised when the computer responded with the desired digits. “Houston,” radioed a jubilant Aldrin, “be advised we have a solid lock-on … two hundred thirty-five point fifty nautical miles.”

Jim Lovell and Buzz Aldrin roar into orbit, atop their Titan II booster from Cape Kennedy's Pad 19 on 11 November 1966. Photo Credit: NASA

Jim Lovell and Buzz Aldrin roar into orbit, atop their Titan II booster from Cape Kennedy’s Pad 19 on 11 November 1966. Photo Credit: NASA

However, the astronauts’ success proved short-lived. As they circularized their orbit to align themselves “behind” and “below” the Agena, high above North America, Gemini XII’s radar began giving intermittent readings. It was at this stage that Aldrin’s years of rendezvous work came to the fore: he broke out the intricate charts and reverted to what he called the “Mark One Cranium Computer”—the human brain. In Men from Earth, Aldrin vividly described the hours-long effort: As Lovell piloted Gemini XII, he labored over the charts, barely able to see the closely-printed data, occasionally aware of the passage of orbital daytime into nighttime and vice-versa.

It paid off. Four hours into the mission, Lovell eased the spacecraft’s nose into the Agena’s docking collar and announced, somewhat nonchalantly, “Houston, we are docked.” The response from the ground, delivered with similar excitement, was a simple “Roger.” The potentially serious failure of the rendezvous radar had been overcome by human brainpower and flying abilities. Should a similar contingency occur during a rendezvous situation in orbit around the Moon, Lovell and Aldrin’s work had at least proved that workarounds could be achieved. They had also used barely 280 pounds (127 kg) of their fuel supply in one of the project’s most economical rendezvous efforts.

For the fourth time in eight months, a Gemini was securely linked to an Agena, and Lovell and Aldrin became the second crew to practice undocking and redocking exercises. One attempt by Lovell during orbital darkness caused the docking latches to “hang up,” producing a rather disturbing grinding sound, but he was able to “rock” Gemini XII free without damage. A few minutes later, they switched roles and Aldrin redocked them onto the target. All seemed to be moving exceptionally smoothly as the astronauts prepared for a four-day mission which would establish itself as a fitting end for Project Gemini and carried excited hope for Project Apollo and the voyage to the Moon.

 

The second part of this article will appear tomorrow.

 

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