Triumph of the Mark One Cranium Computer: The Flight of Gemini XII (Part 2)

Buzz Aldrin participates in a session of extravehicular activity (EVA) in November 1966. Although his activities broke little new ground, Aldrin successfully demonstrated the intricacies of EVA, ahead of Project Apollo. Photo Credit: NASA

Buzz Aldrin participates in a session of extravehicular activity (EVA) in November 1966. Although his activities broke little new ground, Aldrin successfully demonstrated the intricacies of EVA, ahead of Project Apollo. Photo Credit: NASA

Almost four decades ago, on 11 November 1966, astronauts Jim Lovell and Edwin “Buzz” Aldrin rocketed into orbit aboard Gemini XII to complete a four-day mission which would demonstrate many of the capabilities that NASA would someday need for the first piloted landing on the Moon. As noted in yesterday’s history article, the astronauts completed a flawless rendezvous and docking with an Agena target vehicle. Original plans, laid out before launch, had called for a reboost to high altitude, but this had to be abandoned eight minutes after the Agena lifted-off when its engine suffered a momentary decay in thrust chamber pressures and a drop in turbine speed. Instead, the astronauts were directed to turn their attention to solar eclipse photography; this task had been a scheduled part of their mission had they launched on 9 November, but the two-day delay caused it to be dropped. Now that the Agena reboost had been cancelled, it was reinstated, thanks to the input of Gemini XII Experiments Advisory Officer James Bates. 

The inclusion of Bates’ recommendation marked a shift in operations, with the scientists’ representative, for the first time, being allowed to participate as a member of the flight control team in the main Mission Control room. Moreover, it was determined that the Agena’s secondary propulsion system had enough power to orient the spacecraft for an eight-second photographic pass at the proper time. At 10:51 p.m. EST, a little over seven hours into the mission, Lovell duly fired the target’s smaller engines to reduce the combination’s velocity by 42 feet/sec (13 meters/sec). The adjustment was successful and, after their first sleep period, the astronauts were advised to perform a second firing. Sixteen hours after launch, they reported seeing the eclipse “right on the money,” cutting a swath across South America from north of Lima down to the southernmost tip of Brazil.

At first, it had seemed to the disgruntled crew that the second Agena burn might throw out the remainder of their schedule and adversely affect the start of Aldrin’s first EVA. It did not, and at 11:15 a.m. on 12 November, some 20 minutes before orbital sunset, Aldrin cranked open his hatch and pushed his helmeted head outside. “The hatch rose easily,” he wrote in his memoir, Men from Earth, “and I rose with it, floating above my seat, secured to the spacecraft by short oxygen inflow and outflow umbilical hoses.” Years later, he would vividly describe the immensity of the Universe all around him, remember the absence of any sense of speed, and recall the curvature of Earth.

Demonstrating the cramped nature of the Gemini spacecraft, this view of Gemini XII shows Jim Lovell and Buzz Aldrin in what became their orbital home for four days in November 1966. Photo Credit: NASA

Demonstrating the cramped nature of the Gemini spacecraft, this view of Gemini XII shows Jim Lovell and Buzz Aldrin in what became their orbital home for four days in November 1966. Photo Credit: NASA

Aldrin quickly set to work on his first task: dumping a small bag of used food pouches, which he watched slowly tumble away like a top, straight “above” him. Next, he moved on to quickly attach cameras onto brackets to photograph star fields on ultraviolet film and retrieved a micrometeoroid package, which he passed to Lovell. Unlike Cernan and Gordon, he did not overheat, thanks partly to regularly scheduled rest breaks of two minutes apiece, and he returned inside Gemini XII at 1:44 p.m. after 2.5 hours.

His real work had yet to begin. The mission’s second period of EVA, which got underway at 10:34 a.m. on 13 November, required Aldrin to move away from the spacecraft on a 29.5-foot (9-meter) tether. He set up a movie camera to allow flight controllers to monitor his performance, then moved to Gemini XII’s nose and affixed a waist restraint strap to the docking adaptor. Next, he removed a tether from the Agena’s nose and snapped it onto the Gemini, connecting the two vehicles for a gravity gradient exercise scheduled for later in the mission. He then maneuvered himself to the rear of the spacecraft and slipped his boots into a pair of foot restraints nicknamed “golden slippers.” These, coupled with two small waist tethers, kept him anchored securely, and Aldrin was able to satisfactorily complete a number of tool-handling and dexterity tests.

“Back in the buoyancy pool,” he wrote later, “I had torqued bolts and cut metal dozens of times—what I used to call ‘chimpanzee work’—and I had no problem with these chores in space. Someone even put a bright yellow paper Chiquita Banana sticker at my busy box.” He was even able to wipe Lovell’s window (who asked him to change the oil, too) before returning to the cabin after two hours outside. Back on Earth, Aldrin would claim that he had personally solved many of the problems of EVA, arousing criticism among the other astronauts, including  Gene Cernan, who felt that his tasks were nowhere near as difficult as theirs. “Quite frankly,” Cernan wrote in his autobiography, The Last Man on the Moon, “we said he was only working a monkey board. Draw your own conclusions.”

Stunning perspective of Florida, the Bahamas and Cuba, captured by the Gemini XII astronauts. Photo Credit: NASA

Stunning perspective of Florida, the Bahamas, and Cuba, captured by the Gemini XII astronauts. Photo Credit: NASA

Shortly after Aldrin’s return inside Gemini XII, the men completed their evaluation of the tether by undocking from the Agena. The tether tended to remain slack, although they believed that slow gravity gradient stabilization was achieved. “Within minutes,” wrote Aldrin, “the two vehicles had stabilized without the aid of thrusters.” After two full orbits connected in this fashion, they finally fired an explosive squib to jettison the tether at 7:37 p.m. on 13 November.

Aldrin’s record-breaking 5.5 hours of cumulative EVA experience concluded the following day, 14 November, when he ventured outside at 9:52 a.m. for a second stand-up period, lasting 55 minutes. He dumped unneeded equipment overboard, together with a sack containing his umbilical tether and two rubbish bags, and took one last lingering look at Earth below him: the vast land mass of Indochina … and thought of his friend, Sam Johnson, with whom he had undergone flight training and who was at that very moment a prisoner of war somewhere in North Vietnam.

Lovell and Aldrin’s four-day mission had brought Project Gemini to a spectacular ending and demonstrated rendezvous, docking, gravity gradient tethered operations, and the ability of skilled human pilots to calculate a rendezvous with sextants and charts and a slide rule and pencil. Such human skills, using, in Aldrin’s own words, the Mark One Cranium Computer, had relaxed managers’ concerns about the viability of astronauts being able to perform a manual rendezvous, if necessary, in orbit around the Moon.

Jim Lovell (right) and Buzz Aldrin greet the crew of the U.S.S. Wasp after their epic four-day space voyage. Photo Credit: NASA

Jim Lovell (right) and Buzz Aldrin greet the crew of the U.S.S. Wasp after their epic four-day space voyage. Photo Credit: NASA

A re-entry controlled completely by the computers brought Gemini XII into the Atlantic, barely 2.9 miles (4.8 km) from its target impact point, at 2:21 p.m. on 15 November. Within 30 minutes of splashdown, Lovell and Aldrin were safely aboard the aircraft carrier U.S.S. Wasp. The only unexpected event during re-entry had come at the onset of peak G loads, when a pouch containing books, filters, and equipment broke free from the sidewall and landed on Lovell’s lap. By this time, both men had unstowed the D-rings for their ejection seats and Lovell fought the urge to catch the pouch, lest he accidentally grab and pull the ring. “I didn’t want to see myself punching out right at this high heating area,” he said later.

With the safe return of Lovell and Aldrin to Earth, many of the procedures needed to get to the Moon and back had been thoroughly tested. EVA suits had been used for extended periods, and five astronauts had completed useful tasks outside. Unlike Alexei Leonov’s swim in the void 20 months earlier, Lovell and Aldrin had actually begun to demonstrate an astronaut’s ability to really work in space. It provided the closest analogue yet attained of what working on the lunar surface might be like. Rendezvous, despite its complexity, had been completed with seemingly effortless ease by six Gemini crews … and Lovell and Aldrin’s work had shown it could be done without the aid of radar.

In a very real sense, Gemini XII helped lay the final cornerstone for the work which Apollo crews would one day need in their voyages to the Moon. With a little more than three years remaining before the late President John F. Kennedy’s deadline of boots in the lunar dust by 1970, the heat was cranking up for NASA to get started on Project Apollo, with the first mission into Earth orbit planned for early 1967. Those next few years would begin with the hideous tragedy of Apollo 1, but NASA and its remarkable workforce would respond with magnificent resilience to achieve their exalted goal.

 

This is part of a series of history articles, which will appear each weekend, barring any major news stories. Next week’s article will focus on Apollo 12, which performed humanity’s second manned landing on the Moon in November 1969.

 

 

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1 comment to Triumph of the Mark One Cranium Computer: The Flight of Gemini XII (Part 2)

  • Wonderfully written two-part series on Gemini 12. The program was brilliantly planned and executed by the scientists, engineers and the astronauts leading to mankind’s first excursion to another world.