Sunday, November 20, 2016

50 Years Ago: Gemini 12 Ends Program with Success

Gemini 12 lifts off on the Titan rocket.
This last week marks the 50th anniversary of the successful conclusion of the Gemini space program. On November 11, 1966, the last two astronauts to fly in the Gemini space craft began a mission to resolve some of the troubles encountered during EVAs. 

Aldrin (L) and Lovell (R) standing in a Gemini training capsule.
The commander of Gemini 12 was Jim Lovell, veteran Navy pilot, who had last flown on the Gemini 7 with Frank Borman. That flight was notable for it's 14-day endurance mission (estimated to be the time astronauts would live in space going to the Moon and returning home). Gemini 7 was also part of the first actual rendezvous in space, with Gemini 6A. Making his first trip into space, was rookie Gemini pilot Edwin "Buzz" Aldrin. Aldrin had been a combat pilot in the Korean War. He then attended MIT where he obtained a Doctorate in Science in Astronautics, starting his work on advanced space rendezvous calculations. Eventually he would earn the nickname, "Dr. Rendezvous."

Launch of Gemini 12's partner, the Agena target vehicle on board an Atlas rocket.

The mission started with the launch of an Altas rocket from pad 14 at Cape Canaveral. The plan on this mission was for the Gemini 12 to follow behind, catch up to the Agena, then dock with it. It was planned for Aldrin to perform several EVAs including a spacewalk out to the Agena. They would use the Agena's engines to boost the pair into a higher orbit, and then perform a separation followed by a tethered spacecraft experiment as had been done on previous Gemini missions. During the insertion into orbit, however, there was a slight malfunction in the motor, and it was decided after docking that the boost to higher orbit would not be attempted. After the mission, an attempt was made to control the engine from the ground, and it did not activate in any case.

View from close to the pad of the successful launch.
Th launch of the Titan carrying Gemini 12 took place about 90 minutes later, to enable the crew to approach the Agena from about an orbit behind. Liftoff took place from Pad LC-19. During the moment of staging as the rocket first stage was jettisoned, engineers noticed a rupture in the first stage oxidizer tank. Gemini 12 reached orbit and proceeded with catching up to the Agena and docking with it the next day, November 12. There was a failure in the rendezvous radar, and the docking was then performed manually.
Picture by Aldrin of the nose of the Gemini docked with the Agena Target Vehicle.
View of Aldrin outside the Gemini spacecraft.
Aldrin then exited the Gemini for his tethered spacewalk. This Gemini mission differed from previous missions in that extra handholds had been placed on the spacecraft and Agena, which would give Aldrin an advantage in moving and maneuvering between the craft. Also, before the mission, Aldrin had made much use of training preparations using a swimming pool to practice techniques he would use for this mission. These techniques would become standard practice for astronauts from now on.
Photo by Lovell of Aldrin performing a stand-up experiment during the second EVA.
During the first EVA of over 2 hours, Aldrin proved that the extra practice and handholds made a huge difference in relieving a spacewalker from extra duress and exhaustion. He retrieved a micro-meteorite shield from the Agena, and performed other experiments while moving about, including a trip to the rear of the Gemini service module. In his second EVA, he stayed in the Gemini hatch and performed further experiments there, including additional photography and extended tool techniques. After the second EVA, the spacecraft undocked for the tethered ship activity. 
View of the tethered Agena target vehicle and tether.
The Gemini 12 backed off a bit from the Agena and began maneuvering into a slow spin around the Agena. Similar to previous attempts, most of the time the tether did not stay tight but the experiment was considered a success. The tether was then released and the Gemini backed off to a safer distance.
Aldrin took this picture of the Gemini's nose during the third EVA.


Aldrin made a third, stand-up EVA the next day on the 14th. He took more pictures and performed a few more experiments. While the previous EVAs had each been over 2 hours, this was a shorter one for 55 minutes. When he closed the hatch, it was the last time a Gemini space suit would be used in an EVA, From here on out, EVAs would use Apollo - era designs.

Helicopter Point-of-view of Lovell being hoisted up from the recovered Gemini. This is a good view of the flotation "collar" that Navy frogmen would place around the capsule to stabilize it during recovery.
Gemini 12 performed perfect re-entry procedures and came back home on November 15. They splashed down only 5 kilometers off-target, and were televised from the recovery ship USS Wasp. The astronauts were taken up to a helicopter and flew back to the carrier.  Upon their safe return, Gemini Space Program space activities had ended. It was time for Apollo.
Aldrin and Lovell receive a happy welcome back on board USS Wasp. Both men would fly into space again, with Lovell making two more Apollo missions.

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