Gemini 6A
Mission type | Space rendezvous |
---|---|
Operator | NASA |
COSPAR ID | 1965-104A |
SATCAT no. | 1839 |
Mission duration | 1 day, 1 hour, 51 minutes, 24 seconds |
Distance travelled | 694,415 kilometers (374,954 nautical miles) |
Orbits completed | 16 |
Spacecraft properties | |
Spacecraft | McDonnell . Phrase m |
Launch mass | 3,546 kilograms (7,818 lb) |
Crew | |
Crew size | 2 |
Members | |
Start of mission | |
Launch date | December 15, 1965, 13:37:26 | UTC
Rocket | LC-19 |
End of mission | |
Recovered by | USS Wasp |
Landing date | December 16, 1965, 15:28:50 | UTC
Landing site | North Atlantic Ocean 23°35′N 67°50′W / 23.583°N 67.833°W |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth orbit |
Perigee altitude | 270 kilometers (150 nautical miles) |
Apogee altitude | 274 kilometers (148 nautical miles) |
Inclination | 28.9 degrees |
Period | 89.95 minutes |
Epoch | December 15, 1965[1] |
(L-R) Stafford, Schirra |
Gemini 6A (officially Gemini VI-A)
Gemini 6A was the fifth crewed Gemini flight, the 13th crewed American flight, and the 21st crewed spaceflight of all time (including two
Crew
Position | Astronaut | |
---|---|---|
Command Pilot | Walter M. Schirra Jr. Second spaceflight | |
Pilot | Thomas P. Stafford First spaceflight |
Backup crew
Position | Astronaut | |
---|---|---|
Command Pilot | Virgil I. Grissom[3] | |
Pilot | John W. Young |
[3] This was the prime crew of Gemini 3
Support crew
- Charles A. Bassett II (Houston CAPCOM)
- Alan L. Bean (Cape CAPCOM)
- Eugene A. Cernan(Houston CAPCOM)
- Elliot M. See Jr. (Houston CAPCOM)
Mission parameters
- Mass: 3,546 kilograms (7,818 lb)
- Perigee: 161 kilometers (100 miles)
- Apogee: 259.4 kilometers (161.2 miles)
- Inclination: 28.97°
- Period: 88.7 min
Stationkeeping with GT-7
- Start: December 15, 1965 19:33 UTC
- End: December 16, 1965 00:52 UTC
- Duration: 5 hours, 19 minutes
Objective
The original Gemini 6 mission, scheduled for launch on October 25, 1965, at 12:41 pm EDT, had a planned mission duration of 46 hours 47 minutes, completing a total of 29 orbits. It was to land in the western Atlantic Ocean south of Bermuda.
The mission was to include four dockings with the
Original mission plans also included the first live television coverage of the recovery of a US spacecraft at sea from the recovery ship, the US aircraft carrier Wasp. The Wasp was fitted with ground station equipment by
Original mission canceled
On October 25, 1965, Schirra and Stafford boarded their Gemini 6 craft to prepare for launch. Fifteen minutes later, the uncrewed
Agena | GATV-5002 |
---|---|
Mass | 3,261 kilograms (7,189 lb), 7800 lbs. |
Launch site | LC-14 |
Launch date | October 25, 1965 |
Launch time | 15:00:04 UTC |
Exploded | 15:06:20 UTC |
Revised mission
After reviewing the situation, NASA decided to launch an alternate Gemini 6A mission, eight days after the launch of Gemini 7, which was scheduled as a 14-day long-duration mission in December. Gemini 6A would perform the first rendezvous of two spacecraft in orbit, using Gemini 7 as the target, though they would not dock. The crews also discussed the possibility of Stafford performing an EVA from 6A to 7, swapping places with Gemini 7 pilot Jim Lovell, but the commander of Gemini 7, Frank Borman, objected, pointing out that it would require Lovell to wear an uncomfortable EVA suit on a long-duration mission.[8]
Flight
This section needs additional citations for verification. (December 2019) |
First launch attempt
The first attempt to launch the 6A mission (second attempt for Gemini spacecraft No. 6) was on December 12, 1965, at 9:54 a.m. EST.[6] All went well right up to ignition; the engines ignited, but after about 1.5 seconds they abruptly shut down. Since the lift-off clock had started in the spacecraft, mission rules dictated that Wally Schirra, as the commander, had to immediately pull the D-ring between his knees and activate the ejection seats,[9] carrying the astronauts away from the disaster that would be the result of a fully fueled Titan II falling back onto LC-19. However, Schirra did not feel any movement and knew that the booster had not lifted, so he decided not to abort. His quick thinking probably saved the mission as the reliability of the Gemini ejector seats was questionable; the astronauts could have been badly injured from high g-forces as the seats had to launch them at least 800 feet, which was deemed a safe distance from an exploding Titan II.
In addition, the cabin interior had been soaking in pure oxygen for hours. Tom Stafford, in a NASA oral history in 1997, later recalled:
So it turns out what we would have seen, had we had to do that, would have been two Roman candles going out, because we were 15 or 16 psi, pure oxygen, soaking in that for an hour and a half. You remember the tragic fire we had at the Cape. (...) Jesus, with that fire going off and that, it would have burned the suits. Everything was soaked in oxygen. So thank God. That was another thing: NASA never tested it under the conditions that they would have had if they would have had to eject. They did have some tests at China Lake where they had a simulated mock-up of Gemini capsule, but what they did is fill it full of nitrogen. They didn't have it filled full of oxygen in the sled test they had.[10]
Even if the astronauts had not been injured or killed, ejection would ruin the spacecraft and delay the mission for months.
After the Stage I engines ignited and shut down, fuel (
However, the electrical plug turned out to not be the only problem with the booster. Examination of telemetry also showed that the Titan actually began experiencing thrust decay before the plug dropped out. Engine No. 1 was unaffected and nearly reached 100% thrust at shutdown, while Engine No. 2 never transitioned to in-flight performance levels. Engineers spent all night combing through the first stage, but failed to find any cause for the thrust decay. Eventually however, one technician identified the problem, which was a plastic dust cover inside the gas generator that had been carelessly left inside when the booster was assembled months earlier at the Martin-Marietta plant, blocking the flow of oxidizer. The cover was removed and the Titan II cleared for another launch attempt.
Had the inadvertent electrical disconnect not occurred, the abort sensing system would have sent a shutoff command to the Titan at T+2.2 seconds due to the loss of Engine No. 2 chamber pressure. Since launcher release and liftoff would take place at T+3.2 seconds, a pad fallback still would not have occurred in this scenario and the astronauts would have been safe.[11]
Second attempt and rendezvous
The Titan's batteries were replaced and the fuel prevalves, which had opened, were removed and it was decided to launch without them. The second attempt to launch the 6A mission (third attempt for Gemini spacecraft No. 6) was successful on December 15 at 8:37:26 a.m. EST. All went well through launch and ascent; first stage cutoff occurred at T+160 seconds and second stage cutoff at T+341 seconds. Spacecraft separation occurred at T+361 seconds and the crew entered a 100-by-161-mile (161 by 259 km) orbit.
The plan called for the rendezvous to take place on the fourth orbit of Gemini 6. Their first burn came 94 minutes after launch when they increased their speed by 5 meters (161⁄2 feet) per second. Due to their lower orbit they were gaining on Gemini 7 and were only 730 miles, (or 1,175 kilometers), behind. The next burn was at two hours and eighteen minutes when Gemini 6A made a phase adjustment to put them on the same orbital inclination as Gemini 7. They now only trailed by 300 miles (483 km).
The radar on Gemini 6A first made contact with Gemini 7 at three hours and fifteen minutes when they were 434 kilometers (270 mi) away. A third burn put them into a 168-by-170-mile (270 by 274 km) orbit. As they slowly gained, Schirra put Gemini 6A's computer in charge of the rendezvous. At five hours and four minutes, he saw a bright star that he thought was Sirius, but this was in fact Gemini 7.
After several more burns, the two spacecraft were only 130 feet (40 meters) apart. The burns had only used 112 lbs. (51 kilograms) of propellant on Gemini 6A, leaving plenty for some fly-arounds. During the next 270 minutes, the crews moved as close as one foot (30 centimeters), talking over the radio. At one stage the spacecraft were stationkeeping so well that neither crew had to make any burns for 20 minutes.
Schirra said that because there is no turbulence in space, "I was amazed at my ability to maneuver. I did a fly-around inspection of Gemini 7, literally flying rings around it, and I could move to within inches of it in perfect confidence".[12] As the crew sleep periods approached, Gemini 6A made a separation burn and slowly drifted more than 30 kilometers (19 mi) from Gemini 7. This ensured that there would not be any accidental collisions while the astronauts slept.[13]
A Christmas surprise
The next day, before reentry,[13] the crew of Gemini 6A had a surprise:
...this is Gemini VI. We have an object, looks like a satellite going from north to south, up in a polar orbit. He's in a very low trajectory traveling from north to south and has a very high climbing ratio. It looks like it might even be a ... Very low. Looks like he might be going to reenter soon. Stand by one ... You might just let me try to pick up that thing.[14]
At that point, the sound of "Jingle Bells" was heard played on an eight-note Hohner "Little Lady" harmonica and a handful of small bells.[15][16] The Smithsonian Institution claims these were the first musical instruments played in space[17] and keeps the instruments on display.
Reentry
Gemini 6A fired its retro-rockets and landed within 18 kilometers (11 miles) of the planned site in the Atlantic Ocean northeast of
The Gemini 7 and 6A missions were supported by the following U.S. Department of Defense resources: 10,125 personnel, 125 aircraft and 16 ships.[citation needed]
Insignia
Walter Schirra explained the patch in the book All We Did Was Fly to the Moon:
The Gemini 6 patch is hexagonal in shape, reflecting the mission number; and the spacecraft trajectory also traces out the number "6". The Gemini 6 spacecraft is shown superimposed on the "twin stars" Castor and Pollux, for "Gemini". I designed the patch to locate in the sixth hour of celestial right ascension. This was the predicted celestial area where the rendezvous should occur (in the constellation Orion). It finally did occur there.
The original patch had called the flight GTA-6 (for Gemini-Titan-Agena) and showed the Gemini craft chasing an Agena. It was changed when the mission was altered to depict two Gemini spacecraft.
Spacecraft location
The spacecraft is currently on display at the
Before being moved to Oklahoma, the spacecraft was displayed at the
See also
- Splashdown (spacecraft landing)
References
This article incorporates public domain material from websites or documents of the
- ^ McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved March 23, 2014.
- ^ Hacker, Barton C.; Grimwood, James M. (September 1974). "Chapter 11 Pillars of Confidence". On the Shoulders of Titans: A History of Project Gemini. NASA History Series. Vol. SP-4203. NASA. p. 239. Archived from the original on 2010-01-13. Retrieved 2013-09-26. With Gemini IV, NASA changed to Roman numerals for Gemini mission designations.
- ^ a b "Gemini 6 Back-up Crew". NASA. March 23, 2008. Retrieved January 6, 2018.
- ^ "Here Is The Condensed Flight Plan For Gemini 6", Williamson, WV Daily News, Oct 25, 1965
- ^ "Live TV From Wasp For Gemini-6 Flight,", Pittsburgh Post-Gazette, Oct 22, 1965
- ^ a b "Gemini 6". www.astronautix.com. Archived from the original on 2016-12-28. Retrieved 2024-04-04.
- ^ "Gemini 6 Space Shot Fails", Glasgow Herald, Oct 26, 1965
- ^ "Toughest Space Assignment Yet By Gemini, They'll Try It Twice", Ocala Star-Banner, Oct 29, 1965
- ^ "Gemini Ejection Seat". space1.com. Retrieved 2018-06-28.
- ^ Stafford, Thomas P. (October 15, 1997). "Thomas P. Stafford Oral History". Johnson Space Center Oral History Project (Interview). Interviewed by William Vantine.
- ^ "Launch Vehicle No. 6 Flight Evaluationx | PDF | Project Gemini | Space Rendezvous".
- ^ Agle, D. C. (September 1998). "Flying the Gusmobile". Air & Space.
- ^ )
- ^ "Gemini VI Voice Communications" (PDF). NASA. p. 116, timestamp 23:57:30.
- ^ "NASA Mum on 'Jingling'". The Palm Beach Post. December 17, 1965. Retrieved April 1, 2023 – via newspapers.com.
- YouTube
- ^ Smithsonian magazine, December 2005
- ^ Pearlman, Robert (July 31, 2018). "Museum Move Reunites Historic Gemini 6 Spacecraft with its Pilot". Space.com. Retrieved July 31, 2018.
External links
- NASA Gemini 6 press kit for cancelled mission - Oct 20, 1965
- NASA Gemini 7/Gemini 6 press kit - Nov 29, 1965
- Gemini 6 Mission Report (PDF) - October 1965 cancelled mission
- Gemini 6/Agena target vehicle 5002 systems test evaluation (PDF) December 1965
- The short film Proud Conquest : Gemini VI and VII is available for free viewing and download at the Internet Archive.
- Spaceflight Mission Patches
- http://www.collectspace.com/news/news-092703a.html
- Color newsreel footage documenting the cancelled mission of October 1965 (1965) from British Pathé (Record No:41116) at YouTube