Gemini 9A (officially Gemini IX-A) was a 1966 manned spaceflight in NASA's Gemini program. It was the 7th manned Gemini flight, the 13th manned American flight and the 23rd spaceflight of all time (includes X-15 flights over 100 km).
Mission Insignia
Mission Statistics
Mission:Gemini IX-A
Number of Crew Members: 2
Launch:June 3, 1966
13:39:33.335 UTC
Cape Canaveral LC19
Landing:June 6, 1966
3:22:28 UTC
25 13.8' N, 136 0' E
Duration:3 days, 20 min, 50 seconds
Orbits: 47
Distance:2,020,741 km


The crew for Gemini 9A was Thomas Stafford (Commander) and Eugene Cernan (Pilot). Stafford had flown once before on Gemini 6A. The reason he flew so soon, was that he and Cernan were actually the backup crew. The original crew, Elliott See and Charles Bassett were both killed when their plane crashed into the very building were the spacecraft was being built on on February 28, 1966.


The original Gemini 9 mission was intended to be a repeat of the shortened Gemini 8 mission. The crew would dock with an Agena Target Vehicle and perform an EVA. But once again the Agena caused problems like it had on Gemini 6. Once again the Agena exploded during launch, but this time there was an alternative.

The augmented target docking adapter or the ATDA had been designed and built by McDonnell, the manufacturers of the Gemini spacecraft. It was basically a short cylinder with a docking cone on the front. It had all the systems that the Gemini would need for rendezvous but lacked a propulsion unit. It was built using already tested equipment and launched using the Atlas-SLV3 rocket.

As well as the docking there was also a planned EVA by Cernan. The plan was for him to move to the rear of the spacecraft and strap himself into the Air Force's Astronaut Maneuvering Unit. This was the first 'rocket pack' and a predecessor of the Manned Maneuvering Unit used by Shuttle astronauts in the 1980s. It had its own propulsion, stabilization system, oxygen and telemetry for the biomedical data and systems. It used hydrogen peroxide for propellant.


Launch Attempts

The first launch attempt of Gemini 9A was on
June 1. The ATDA had launched perfectly into a 298 kilometre orbit, though telemetry from it indicated that the launched shroud had failed to open properly. But the Gemini spacecraft was not able to launch the same day as planned. At T-3 minutes, the ground computers could not contact the Gemini computers for some reason and the 40 second launch window opened and closed without the launch.

The second launch attempt went perfectly with the spacecraft entering into orbit. With this launch, Stafford could stay that the had been strapped into a spacecraft six times ready for launch.


There first burn was 49 minutes after launch. They added 22.7 metres per second to their speed which put them in a 160 to 232 kilometres orbit. Their next burn was designed to correct phase, height, and out-of-plane errors. They pointed the spacecraft 40° down, and 3° to the 'left'. The burn added 16.2 metres per second to their speed and put them in a 274 by 276 kilometres orbit, closing at 38 metres per second on the ATDA.

The first radar readings were when they were 240 km away and they had a solid lock at 222 km. Their first sight came 3 hours and 20 minutes into the mission when they were 93 km way. They noted that they could see the flashing lights on the ATDA designed to aid identification from a distance. This made them hope that the launch shroud had in fact been jettisoned and that the telemetry was wrong.

As they got closer they found that in fact the shroud had half come off. Stafford described "It looks like an angry alligator out here rotating around". He asked if maybe he could use the spacecraft to open the 'jaws' but the ground decided against it.

The ADTA as seen by the Gemini 9A crew
The crew described that the shrouds explosive bolts had fired but a two neatly taped lanyards were holding the shroud together. It was decided that it would be too dangerous for an astronaut to cut the lines, as there were too many sharp edges around.

The reason for the laynards was soon discovered. Douglas built the shroud, but Lockheed attached it to the rocket, while McDonnell built the ATDA. A Douglas engineer had made a practise run with the McDonnell crew but didn't give them instructions on the final procedures which involved the laynards. The McDonnell crew had the Douglas instructions for this procedure which said, "See blueprint", but there was no blueprint. So the McDonnell technicians decided to tape down the loose laynards as it seemed like the sensible thing to do.

The crew then did some planned rendezvous practice that involved them moving away from the ATDA by firing their thrusters and then practising approaching from below the target. They then got some much needed food and rest.

On the second day of the mission, they again approached the ATDA, this time from above. Once they were stationkeeping along side, they were given permission for their EVA. But they were tired and Stafford didn't want to waste fuel keeping himself near the ATDA during the EVA when there was little they could do with it. So it was decided to postpone the EVA until the third day.


On this third day, the second ever EVA by an American started at just after orbital sunrise. It was planned that Cernan would spend 167 minutes outside the spacecraft--twice around the world.

Cernan found the going tough. Every movement that he made caused a reaction, and even though there were handholds installed on the spacecraft after the comments of Ed White after his EVA on Gemini 4, Cernan found it hard to control himself. Even the umbilical was annoying and hard to control.

He finally reached the rear of the spacecraft and began to check and prepare the AMU. This took longer than planned due to lack of hand and foot holds. He was unable to get any leverage which made it hard to turn valves or basically anything that involved moving. All this was made worse when after sunset, his faceplate fogged up.

At this point Cernan decided that there was alot of risk in continuing the EVA. He couldn't see very well and had found that he could not move very well. He would have to disconnect himself from the umbilical that attach him to the Gemini (though would still be attached by a longer thinner lead), after he had connected himself to the AMU. But when he had finished with the AMU he would somehow have to take the thing off with one hand, while the other held onto the spacecraft. So he decided to cancel the rest of the EVA, with Stafford and Mission Control concurring.

He managed to move himself back to the cockpit and Stafford held onto he legs to give a rest. After trying to remove a mirror mounted to the side of the spacecraft, his suit cooling system overheated and his faceplate fogged up completely, meaning he couldn't see. He and Stafford managed to get the hatch closed and repressurised. Cernan had spent 128 minutes outside the spacecraft.

As well as the rendezvous and EVA, the other major objective of the mission was to carry out seven experiments. The only medical experiment was M-5, which measured the astronauts reactions to stress by measuring the intake and output of fluids before, during and after the flight.


There were two photography experiments. S-1 hoped to image the Zodiacal Light during a EVA, but this was changed to inside the spacecraft after the problems encoutered by Cernan. And S-11 involved the astronauts trying to image the Earth's airglow in the atomic oxygen and sodium light spectra. They took 44 pictures as part of this experiment with three being of actual airglow.

S-10 had hoped to retrieve a Micrometeorite Collector from the ATDA, though this failed after they were unable to dock with it. They were able to image it though during there close approaches. Instead they were able to recover the collector from the Gemini spacecraft (S-12). D-12 also failed as it was an investigation of controlling the AMU.

The last experiment was D-14 which was UHF/VHF Polarization. This was an extendable antenna mounted on the adapter section at the rear of the spacecraft. It was hoped to obtain information about communication through the ionosphere. Six trials of this were performed but the antenna was broken by Cernan during his EVA.


The day of the EVA was also their last in space. On their 45th revolution of the Earth, they fired the retrofire rockets that slowed them down so that they would reenter. This time the computer worked perfectly, meaning they landed only 700 metres from the planned landing site and were close enough to see the prime recovery ship, the USS Wasp.

After the mission it was decided to set up a Mission Review committee. Their job was to make sure that the objectives planned for each mission were realistic and whether they had a direct benefit for Apollo.


The Gemini 9 patch is quite simple. It is in the shape of a shield and shows the Gemini spacecraft docked to the Agena. There is a spacewalking astronaut, with his tether forming the shape of a number 9. Although the Gemini 9 mission was changed so that it docked with the ATDA, the patch was not changed. It is also not known whether Bassett and See had designed a patch for the mission as the original crew.

Capulse Location

The capusle is on display at the KSC Visitors Center, Kennedy Space Center, Florida.

External links

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Gemini 8
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Gemini 10