Science Fair Project Encyclopedia
|McDonnell Gemini spacecraft|
Gemini spacecraft in orbit.
|Crew:||two; cmd pilot, pilot|
|Height:||18.6 ft||5.67 m|
|Diameter:||10 ft||3.05 m|
|Volume:||90 ft3||2.55 m3|
|Reentry module:||4,372 lb||1,983 kg|
|Retrograde module:||1,303 lb||591 kg|
|Equipment module:||2,815 lb||1,277 kg|
|Total:||8,490 lb||3,851 kg|
|Retros (solid fuel) x 4:||2,500 lbf ea||11.12 kN|
|Reentry Control System (N2O4/MMHH) x 16:||25 lbf ea||111 N|
(N2O4/MMHH) x 2:
|85 lbf ea||378 N|
(N2O4/MMHH) x 6:
|100 lbf ea||445 N|
(N2O4/MMHH) x 8:
|25 lbf ea||111 N|
|Endurance:||14 days||206 orbits|
|Apogee:||250 miles||402 km|
|Perigee:||100 miles||160 km|
|Spacecraft delta v:||728 ft/s||222 m/s|
|Gemini spacecraft diagram|
Gemini spacecraft diagram (NASA)
|McDonnell Gemini Spacecraft|
Project Gemini was the second human spaceflight program in which the United States of America sent humans into space, between Projects Mercury and Apollo, during the years 1963-1966. Its objective was to develop techniques for advanced space travel, notably those necessary for Apollo, whose objective was to land men on the Moon. Gemini missions involved extravehicular activity and orbital maneuvers including rendezvous and docking.
Gemini was originally seen as a simple extrapolation of the Mercury program, and thus early on was called Mercury Mark II. The final program had little in common with Mercury and was in fact superior to even Apollo in some ways. (See Big Gemini.) This was mainly a result of its late start date, which allowed it to benefit from much that had been learned by that time on the Apollo project (which, despite its later launch dates, was actually begun before Gemini).
Its primary difference from Mercury was that the earlier spacecraft had all systems other than the reentry rockets sited within the capsule, nearly all of which had to be accessed through the astronaut's hatchway, while Gemini had many power, propulsion, and life-support systems in a detachable module like a huge bowl; many components in the capsule itself were reachable each through its own small access door. The original intention was for Gemini to use a paraglider instead of a parachute, and the crew to be seated upright controlling the forward motion of the craft before its landing. To facilitate this, the parachute cord does not just attach to the nose of the craft; there is an additional attachment point for balance near the heat shield. This cord is covered by a strip of metal between the doors. Early, short-duration missions had their electrical power supplied by batteries; later endurance missions had the first fuel cells in manned spacecraft.
The "Gemini" designation comes from the fact that each spacecraft held two men, as "gemini" in Latin means "twins". Gemini is also the name of the third constellation of the Zodiac and its twin stars, Castor and Pollux.
Unlike Mercury, which could only change its orientation in space, the Gemini capsule could alter its own orbit. It could also dock with other spacecraft--one of which, the Agena Target Vehicle, had its own large rocket engine which was used to perform large orbital changes. Gemini was the first American manned spacecraft to include an onboard computer, the Gemini Guidance Computer , to facilitate management and control of mission maneuvers.
The main contractor was McDonnell who had lost out on main contracts for the Apollo Project. McDonnell sought to extend the programme by proposing a Gemini craft could be used to fly a cislunar mission and even achieve a manned lunar landing earlier and at less cost than Apollo but these were rejected.
The Gemini program cost $5.4 billion in 1994 dollars. See NASA Budget.
The National Aeronautics and Space Administration NASA announced December 7, 1961, a plan to extend the existing manned space flight program by development of a two-man spacecraft. The program was officially designated Gemini on January 3, 1962.
The Gemini program was managed by the Manned Spacecraft Center, Houston, Texas, under direction of the Office of Manned Space Flight, NASA Headquarters, Washington, D.C, Dr. George E. Mueller, Associate Administrator of NASA for Manned Space Flight , served as acting director of the Gemini program. William C. Schneider, Deputy Director of Manned Space Flight for Mission Operations, served as Mission Director on all Gemini flights beginning with Gemini V.
The Manned Spacecraft Center Gemini effort was headed by Dr. Robert R. Gilruth, director of the Center, and Charles W. Matthews, Gemini Program Manager.
The Gemini Program was conceived after it became evident to NASA officials that an intermediate step was required between the projects Mercury and Apollo. The major objectives assigned to Gemini were:
- To subject two men and supporting equipment to long-duration flights, a requirement for projected later trips to the moon or deeper space.
- To effect rendezvous and docking with other orbiting vehicles, and to maneuver the docked vehicles in space, using the propulsion system of the target vehicle for such maneuvers.
- To perfect methods of reentry and landing the spacecraft at a pre-selected land-landing point.
- To gain additional information concerning the effects of weightlessness on crew members and to record the physiological reactions of crew members during long duration flights.
The United States Air Force had an interest in the system, and decided to use their own modification of the spacecraft as the crew vehicle for the Manned Orbiting Laboratory. To this end, one of the unmanned Gemini spacecraft was refurbished and flown again atop a mockup of the MOL, sent into space by a Titan III-M . This was the first time a spacecraft went into space twice.
The USAF also had the notion of adapting the Gemini spacecraft for trying out military applications, such as crude observation of the ground (no specialized reconaissance camera could be carried) and practicing making rendezvous with suspicious satellites. This project was called Blue Gemini . The US Air Force did not like the fact that Gemini would have to be recovered by the US Navy, so they intended for Blue Gemini eventually to use the paraglider and land on three skids, something from the original design of Gemini.
At first some within NASA welcomed sharing of the cost with the USAF, but it was later agreed that NASA was better off operating Project Gemini by itself. MOL was cancelled in 1968 and Blue Gemini too was cancelled without any use by military astronauts. .
Gemini involved 12 flights, including two unmanned flight tests of the equipment.
- Gemini III , MOLLY BROWN
March 23, 1965
04 hours, 52 minutes 31 seconds
First manned Gemini flight, three orbits.
The only major incident during the mission involved a contraband corned beef sandwich that Young had snuck on board. The crew each took a few bites before the sandwich had to be restowed. The crumbs it released could have wreaked havoc with the craft's electronics, so the crew were reprimanded when they returned to Earth. Other crews were warned not to pull the same type of stunt again.
June 03-07, 1965
4 days 1 hour 56 min 12 seconds
Included first extravehicular activity (EVA) by an American; White's "space walk" was a 22 minute EVA exercise.
August 21-29, 1965
7 days 22 hours 55 min 14 seconds
First week-long flight
First use of fuel cells for electrical power; evaluated guidance and navigation system for future rendezvous missions. Completed 120 orbits.
December 04-18, 1965
13 days, 18 hours, 35 minutes 1 seconds
When the original Gemini VI mission was scrubbed because its Agena target for rendezvous and docking failed, Gemini VII was used for the rendezvous instead. Primary objective was to determine whether humans could live in space for 14 days.
December 15-16, 1965
1 Day 1 hour 51 min 24 seconds
First space rendezvous accomplished with Gemini VII, station-keeping for over five hours at distances from 0.3 to 90 m (1 to 295 ft).
March 16, 1966
10 hours, 41 minutes 26 seconds
Accomplished first docking with another space vehicle, an unmanned Agena stage. A malfunction caused uncontrollable spinning of the craft; the crew undocked and effected the first emergency landing of a manned U.S. space mission.
June 03-06, 1966
3 days, 21 hours
Rescheduled from May to rendezvous and dock with augmented target docking adapter (ATDA) after original Agena target vehicle failed to orbit. ATDA shroud did not completely separate, making docking impossible. Three different types of rendezvous, two hours of EVA, and 44 orbits were completed.
July 18-21, 1966
2 days 22 hours 46 min 39 seconds
First use of Agena target vehicle's propulsion systems. Spacecraft also rendezvoused with Gemini VIII target vehicle. Collins had 49 minutes of EVA standing in the hatch and 39 minutes of EVA to retrieve experiment from Agena stage. 43 orbits completed.
September 12-15, 1966
2 days 23 hours 17 min 8 seconds
Gemini record altitude, 1,189.3 km (739.2 mi) reached using Agena propulsion system after first orbit rendezvous and docking. Gordon made 33-minute EVA and two-hour standup EVA. 44 orbits.
November 11-15, 1966
James A. Lovell, Jr., Edwin "Buzz" Aldrin
3 days, 22 hours, 34 minutes 31 seconds Final Gemini flight. Rendezvoused and docked manually with its target Agena and kept station with it during EVA. Aldrin set an EVA record of 5 hours, 30 minutes for one space walk and two stand-up exercises.
Gemini-Titan launches and serial numbers
The Gemini-Titan launch vehicles, like the Mercury-Atlas vehicles before them, were ordered by NASA through the U. S. Air Force. The Titan II's were in reality missiles. The Air Force had a relationship with the missile manufacturers, not NASA. The Gemini-Titan II rockets were assigned U.S. Air Force serial numbers. These serial numbers were painted in four places on each Titan II. On opposite sides, at the bottom of the first stage and on opposite sides, at the bottom of the second stage. U.S. Air Force crews maintained Launch Complex 19 and prepared and launched all of the Gemini-Titan II launch vehicles.
These are the USAF serial numbers assigned to the Gemini-Titan launch vehicles. They were ordered in 1962 so the serial is "62-12XXX", but only "12XXX" is painted on the Titan II:
- 12556 - GLV-1 - Gemini 1
- 12557 - GLV-2 - Gemini 2
- 12558 - GLV-3 - Gemini 3
- 12559 - GLV-4 - Gemini 4
- 12560 - GLV-5 - Gemini 5
- 12561 - GLV-6 - Gemini 6A
- 12562 - GLV-7 - Gemini 7
- 12563 - GLV-8 - Gemini 8
- 12564 - GLV-9 - Gemini 9A
- 12565 - GLV-10 - Gemini 10
- 12566 - GLV-11 - Gemini 11
- 12567 - GLV-12 - Gemini 12
- 12568 - GLV-13 Ordered by NASA 1962, not built, cancelled July 30, 1964
- 12569 - GLV-14 Ordered by NASA 1962, not built, cancelled July 30, 1964
- 12570 - GLV-15 Ordered by NASA 1962, not built, cancelled July 30, 1964
- National Aeronautics and Space Administration
- Titan (rocket family)
- Titan II rocket
- Big Gemini
- Manned Orbiting Laboratory
- Agena Target Vehicle
- Gene Kranz, Failure is Not an Option. Factual, from the standpoint of a chief flight controller during the Mercury, Gemini, and Apollo space programs. ISBN 0743200799
- On the Shoulders of Titans: A History of Project Gemini - NASA report (PDF format)
- Project Gemini technology and operations - A chronology - NASA report (PDF fomat)
- On the Shoulders of Titans: A History of Project Gemini by Barton C. Hacker and James M. Grimwood
- John F. Kennedy Space Center - The Gemini Program
- NASA Project Gemini site
- Space history: Gemini Program space history - Gemini missions spaceflight
- Project Gemini Drawings and Technical Diagrams
- Technical Diagrams and Drawings
- Gemini familiarization Manuals (PDF).
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