Gemini 8
| Mission Insignia | |
|---|---|
 | |
| Mission Statistics | |
| Mission Name: | Gemini 8 |
| Call Sign: | Gemini 8 |
| Number of Crew: | 2 |
| Launch: | March 16, 1966 16:41:02.389 UTC Cape Canaveral LC 19 |
| Agena Docking: Docked: Undocked: | March 16, 1966 22:14 UTC ~22:45 UTC |
| Landing: | March 17, 1966 03:22:28 UTC 25ð 13.8' N 136ð 0' E |
| Duration: | 10 hours 41 minutes 26 seconds |
| Distance Traveled: | ~293,206 km |
| Orbits: | 6.75 |
| Apogee: (1st orbit) | 271.9 km |
| Perigee: (1st orbit) | 159.9 km |
| Period: (1st orbit) | 88.83 m |
| Inclination: | 28.91 deg |
| Mass: | 3,789 kg |
| Crew Picture | |
 Gemini 8 crew portrait (L-R: Scott, Armstrong) | |
| Gemini 8 Crew | |
Gemini 8 (officially Gemini VIII) was a 1966 manned spaceflight in NASA's Gemini program. It was the 6th manned Gemini flight, the 12th manned American flight and the 22nd spaceflight of all time (includes X-15 flights over 100 km).
| Table of contents |
|
2 Mission Parameters 3 Objectives 4 Flight 5 Cause and Outcome 6 Insignia 7 Capsule Location 8 External links |
The main objective of Gemini 8 was to rendezvous and dock with the Agena Target Vehicle, the first ever docking in space. The other main objective was to investigate Extra-Vehicular Activity to a greater extent than on Gemini 4, when Edward White had only spent 20 minutes outside of the spacecraft. On this mission it was planned that Dave Scott would spend up to two hours outside the spacecraft.
Crew
Mission Parameters
See also
Objectives
A second major objective of the Gemini program was completed less than six hours after launch, when Neil Armstrong brought Gemini VIII within 0.9 meters of the preÃÂlaunched Agena target, then slowly docked-the first orbital docking ever. What followed, however, were some of the most hair-raising few minutes in space-program history. The Gemini VIII capsule, still docked to the Agena, began rolling continuously. Never having faced this in simulation, the crew undocked from the Agena, but the problem was a stuck thruster on the spacecraft, which now tumbled even faster, at the dizzying rate of one revolution per second. The only way to stop the motion was to use the capsule's reentry control thrusters, which meant that Armstrong and Scott had to cut short their mission and make an emergency return to Earth 10 hours after launch. They were still nauseated after splashdown, as well as disappointed: Scott had missed out on a planned space-walk. Flight
Agena
It was five months since NASA had tried to launch an Agena and Gemini. This time everything worked perfectly. The Agena put itself into a 298-kilometer circular orbit and orientated itself to the correct attitude for the docking. The Gemini spacecraft itself was put into a 160 by 272 kilometres by its modified Titan II ICBM.
| Gemini 8 | Agena Info |
|---|---|
| Agena | GATV-5003 |
| NSSDC ID: | 1966-019A |
| Mass | 3,175 kg |
| Launch Site | LC-14 |
| Launch Date | March 16, 1966 |
| Launch Time | 15:00:03 UTC |
| 1st Perigee | 299.1 km |
| 1st Apogee | 299.7 km |
| Period | 90.47 m |
| Inclination | 28.86 |
| Reentered | September 15, 1967 |
They found that at 332 kilometres from the Agena that the radar had acquired the target. At 3 hours, 48 minutes and 10 seconds into the mission they performed another burn that put them in a circular orbit 28 kilometres below the Agena. They first sighted the it when they were 140 km away and at 102 km they turned the computer onto automatic.
After Scott had instructed the Agena to turn them 90ð to the right, he noticed that for some strange reason they were in a roll. Armstrong used the Gemini's OAMS to stop the roll, but the moment he stopped using the thrusters, it started again. They immediately turned off the Agena and this seemed to stop the problem for a few minutes. Then suddenly it started again.
Scott noticed that the Gemini attitude fuel had dropped to 30% indicating that it was a problem on their own spacecraft. They would have to undock. After transferring control of the Agena back to the ground they undocked and with a long burst of translation thrusters moved away from the Agena.
It was at that point that the Gemini spacecraft began to roll even faster. It reached one revolution per second. The only thing to do was turn off the OAMS and change to the reentry control system. This would mean they would have to reenter as soon as possible but was the only thing to do if they didn't want to blackout. After steadying the spacecraft they tested each OAMS thruster in turn and found that Number 8 had stuck on.
Planes were also dispatched and the crew of one managed to see the spacecraft as it descended. Three pararescuers jumped from the plane and attached the floation collar to the capsule. Three hours after landing the Mason had the spacecraft on board.
Had Gemini 8 landed in the western Atlantic Ocean (the scheduled recovery area) as planned, the U. S. Navy Atlantic Recovery Fleet's prime recovery ship was the carrier, USS Boxer CV-21. During this time the U.S.S. Wasp (the usual Atlantic Fleet Gemini recovery carrier) was in dry dock for repairs.
The Gemini 8 mission was supported by the following U.S. Department of Defense resources; 9,655 personnel, 96 aircraft and 16 ships.
Several things changed because of this mission. The Deputy Administrator of NASA, Robert Seamans, was at a dinner when the problem arose. Afterwards, he decided that he shouldn't be at public engagements during critical points in flights.
McDonnell, the main contractor on the spacecraft also changed its procedures. Usually, its top engineers would be at Cape Kennedy for the launch, then fly to Mission Control in Houston, Texas for the rest of the mission. The problem occurred while they were still flying over the USA. It was decided from then on that they would have people in both the Cape and Houston.
No conclusive reason for the thruster sticking on was found. It was most probably caused by an electrical short, most likely due to a static electricity discarge. Even if the switch to the thruster was off, power could still flow to it. To prevent reccurrance of this problem, the system was changed, so that the thruster could be isolated.
Rendezvous and Docking
Their first burn was at 1 hour and 34 minutes into the mission, when they lowered their apogee with a 5 second burn. The second burn was at apogee of the second orbit. This time they raised their perigee by adding 15 metres per second to their speed. Their third burn made sure that they were in the same orbital plane. This time they were turned 90ð from their direction of travel and made a burn of 8 metres per second while they were over the Pacific. They then had to make a 0.8 metres per second burn after the ground controller realised that they were slightly off due to problems with the thrusters not shutting off properly.
Agena as seen from Gemini 8The Spin
There was some suspicion on the ground that the Agena attitude system was playing up and it may not have the correct program stored in it. Just before they went off contact with the ground, the crew of Gemini 7 were informed that it anything strange happened they were to turn off the Agena.Landing
It was decided to let the spacecraft reenter one orbit later so that it could land in a place that it could be reached by the secondary recovery forces. It had planned for Gemini 8 to land in the Atlantic, but that was supposed to be three days later on. So the USS Leonard Mason started to steam towards the new landing site 800 kilometres east of Okinawa and 1,000 kilometres south of Yokosuka, Japan.Cause and Outcome
Insignia
The patch was shows the whole specturm of objectives that were hoped to have been accomplished on Gemini 8. The Roman numerals at the bottom are IIVIII, with the first two II being the zodiacal symbol for Gemini and VIII being eight, the mission number. The two stars are Castor and Pollux, which are in the constellation of Gemini.Capsule Location
The capsule is on display at the Neil Armstrong Air and Space Museum, Wapakoneta, Ohio.External links
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