Gemini X was the eighth manned mission and the fourth rendezvous mission of the Gemini Program. The Gemini Atlas-Agena Target Vehicle was launched from Complex 14, Cape Kennedy, Florida, at 3:39:46 p.m. e.s.t. on July 18, 1966. The Gemini Space Vehicle was launched from Complex 19, Cape Kennedy, Florida, at 5:20:27 p.m. e.s.t, on July 18, 1966, with Astronaut John W. Young as the Command pilot and Astronaut Michael Collins as the Pilot. The flight was successfully concluded on July 21, 1966, when the spacecraft was landed within sight of the prime recovery ship at 70:46:39 ground elapsed time. The flight crew elected to be retrieved by helicopter and were on the deck of the prime recovery ship approximately 28 minutes after landing.
Gemini established that radiation at high altitude was not a problem. After docking with their Agena booster in low orbit (Agena #5005 in the photos above), Young and Collins used it to climb another 763.8 kilometers to meet with the dead, drifting Agena left over from the aborted Gemini VIII flight — thus executing the program's first double rendezvous.
With no electricity on board the second Agena, the rendezvous was accomplished with eyes only — no radar. After the rendezvous, Collins space-walked over to the dormant Agena at the end of a 15.24 meter tether, making Collins the first person to meet another spacecraft in orbit. He retrieved a cosmic dust-collecting panel from the side of the Agena, but returned no pictures of his close encounter; in the complicated business of keeping his tether clear of the Gemini and Agena, Collins' Hasselblad camera worked itself free and drifted off into orbit.
Gemini 10 was designed to achieve the objectives planned for the last two missions—rendezvous, docking and EVA. As well as this it was also hoped to dock with the Agena Target Vehicle from the Gemini 8 mission. This Agena's battery power had failed many months earlier and this would demonstrate the ability to rendezvous with a dormant object. It would be also the first mission to fire the Agena's own rocket, allowing them to reach higher orbits.
The Agena launched perfectly for the second time, after problems had occurred with the targets for Gemini 6 and 9. Gemini 10 followed 100 minutes later and entered into a $159.9 \times 268.9$ kilometres (167.1 mi) orbit. They were 1,800 kilometres (1,100 mi) behind the Agena.
Collins discovered that he was unable to use the sextant for navigation as it did not seem to work as expected. At first he mistook airglow as the real horizon when trying to make some fixes on stars. Then the image didn't seem right. He tried another instrument that they had on board but this was not practical to use at it had a very small field of view.
The spacecraft crew fortunately had a backup in the form of the computers on the ground. They made their first burn to put them into a 265 by 272 kilometres orbit. However Young didn't realise that during the next burn he had the spacecraft turned slightly which meant that they introduced an out of plane error. This meant two extra burns were necessary, and by the time they had docked with the Agena, 60% of their fuel had been consumed. It was decided to keep the Gemini docked to the Agena as long as possible as this would mean that they could use the fuel on board the Target Vehicle for attitude control.
The first burn of the Agena engine they made was 80 seconds long and put them in a 294 by 763 kilometres orbit. This was the highest a person had ever been (until the next mission when Gemini 11 went to over 1,000 kilometres (620 mi)). This burn was quite a ride for the crew. Because the Gemini and Agena docked nose to nose, the forces experienced were "eyeballs out" as opposed to "eyeballs in" for a launch from Earth. The crew took a couple of pictures when they reached apogee but were more interested in what was going on in the spacecraft — checking the systems and watching the radiation dosage meter.
After this they had their sleep period which lasted for eight hours and then they were ready for another busy day. First order of business was to make a second burn with the Agena engine to put them into the same orbit as the Gemini 8 Agena. This was at 20:58 UTC on 19 July and lasted 78 seconds and took 105 metres per second off their speed, putting them into a 294 by 382 kilometres (237 mi) orbit. They made one more burn of the Agena to circularise their orbit to 377.6 kilometres (234.6 mi).
It was now time for the first of two EVAs on Gemini 10. This was to be just a standup EVA, where Collins would 'stand' in the open hatch and take some photographs of stars as part of experiment S-13. They used a 70 mm general purpose camera to image the Southern Milky Way in ultraviolet. After orbit sunrise, Collins then photographed a colour plate on the side of the spacecraft (MSC-8) to see whether film reproduced colours accurately in space. They reentered the spacecraft six minutes early when they both found their eyes were irritated. After repressurising they ran the oxygen at high rates and flushed the environment system.
Young and Collins were both tired after the exercise of the EVA and slept well on their second 'night' in space. The next 'morning' they started preparing for the second rendezvous and another EVA.
After undocking from their Agena they thought they sighted the Gemini 8 Agena. It however turned out to be their own Agena 5.5 kilometres (3.4 mi) away, while their target was 176 kilometres (109 mi) away. It wasn't until just over 30 kilometres (19 mi) away that they saw it as a faint star. After a couple more correction burns they were station keeping 3 metres away. They found the Agena to be very stable and in good condition.
48 hours and 41 minutes into the mission, the second EVA began. Collins' first task was to retrieve a Micrometeorite Collector (S-12) from the side of the spacecraft. This he accomplished with some difficulty (similar to that encountered by Eugene Cernan on Gemini 9A). However the collector floated out of the cabin some time later during the EVA and was lost.
He next travelled over to the Agena. He tried to grab onto the docking cone but found this impossible as it was smooth and had no grip. He used a nitrogen-propelled Hand-Held Maneuvering Unit to move himself towards the Gemini and then back to the Agena. This time he was able to grab hold of some wire bundles and retrieved the Micrometeorite Collector (S-10) from the Agena. He decided against replacing it as he could lose the one he had just retrieved.
His last task on this EVA was to test out the gas gun. However this stopped working and meant they finished the EVA after only 25 minutes. It took the crew eight minutes to close the hatch as they had some difficulty with the 50 feet (15 m) of umbilical cord. It was jettisoned along with the chestpack used by Collins an hour later when they opened the hatch for the third and final time.
The last day of the mission was short and retrofire came at 70 hours and 10 minutes into the mission. They landed only 5.6 kilometres (3.5 mi) away from the intended landing site and were recovered by the USS Guadalcanal.
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| Photo S66-45770_G10-M. Clouds over water. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46111_G10-S. Agena #5005, Side view, Range 30M or 98ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46116_G10-S. Agena #5005, Side view, Range 20M or 65ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46122_G10-S. Agena #5005, Side view, Range 14M or 46ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46124_G10-S. Agena #5005, Side view, Range 15M or 49ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46126_G10-S. Agena #5005, Side view, Range 8.5M or 28ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46132_G10-S. Agena #5005, Docking adapter turning toward spacecraft, Range 7.6M or 25 ft. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46249_G10-S. Docked with Agena #5005, excellent view of Agena display panel, glow from Agena P.P.S. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46260_G10-S. Docked with Agena #5005, excellent view of Agena display panel. Credit: NASA/JSC/Arizona State University |
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| Photo S66-46269_G10-S. Inside Gemini, Major Michael Collins. Credit: NASA/JSC/Arizona State University |
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| Scheme of docking between Gemini X spacecraft (left) and Agena Target Vehicle, from NASA's Gemini Program Mission Report GEMINI X (August 1966). Credit: NASA |
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| Color design of the emblem of the Gemini 10 space flight. Roman numeral indicates the tenth flight in the Gemini series. The two spacecraft and their orbital paths symbolize the rendezvous and docking mission of the Gemini and Agena. Credit: NASA |
Sources:
- Sp-168 Exploring Space With A Camera, Section Three (2/2), [174] Man's Ventures Into Space, NASA History
- Gemini 10, Wikipedia
- March to the Moon, Project Gemini, NASA / Arizona State University
- Gemini Program Mission Report, Gemini 10 (PDF)
- NASA Gemini 10 press kit - July 15, 1966 (PDF)
