 | |
| Program overview | |
|---|---|
| Country | United States |
| Organization | NASA |
| Purpose |
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| Status | Completed |
| Program history | |
| Cost |
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| Duration | 1961–1966 |
| First flight |
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| First crewed flight |
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| Last flight |
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| Successes | 10 |
| Partial failures | 2 (Gemini 8 andGemini 9A) |
| Launch site(s) | Cape Kennedy,LC-19 |
| Vehicle information | |
| Crewed vehicle(s) | Gemini capsule |
| Launch vehicle(s) | Titan II GLV |
| Part ofa series on the |
| United States space program |
|---|
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National security space |
Project Gemini (IPA:/ˈdʒɛmɪni/) was the second United Stateshuman spaceflight program to fly. Conducted after the first American crewed space program,Project Mercury, while theApollo program was still in early development, Gemini was conceived in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flewlow Earth orbit (LEO) missions during 1965 and 1966.
Gemini's objective was the development of space travel techniques to support the Apollo mission toland astronauts on the Moon. In doing so, it allowed the United States to catch up and overcome the lead inhuman spaceflight capability theSoviet Union had obtained in the early years of theSpace Race, by demonstrating mission endurance up to just under 14 days, longer than the eight days required for a round trip to theMoon; methods of performingextravehicular activity (EVA) without tiring; and theorbital maneuvers necessary to achieverendezvous anddocking with another spacecraft. This left Apollo free to pursue its prime mission without spending time developing these techniques.
All Gemini flights werelaunched fromLaunch Complex 19 (LC-19) atCape Kennedy Air Force Station in Florida. Theirlaunch vehicle was theTitan II GLV, a modifiedintercontinental ballistic missile.[note 1] Gemini was the first program to use the newly builtMission Control Center at the HoustonManned Spacecraft Center forflight control.[note 2] The project also used theAgena target vehicle, a modifiedAtlas-Agena upper stage, used to develop and practice orbital rendezvous and docking techniques.
The astronaut corps that supported Project Gemini included the "Mercury Seven", "The New Nine", and "The Fourteen". During the program, three astronauts died in air crashes during training, including both members of the prime crew for Gemini 9. The backup crew flew this mission.
Gemini was robust enough that the United States Air Force planned to use it for theManned Orbital Laboratory (MOL) program, which was later canceled. Gemini's chief designer,Jim Chamberlin, also made detailed plans forcislunar and lunar landing missions in late 1961. He believed Gemini spacecraft could fly in lunar operations before Project Apollo, and cost less. NASA's administration did not approve those plans. In 1969, Lukas Bingham proposed a "Big Gemini" that could have been used to shuttle up to 12 astronauts to the planned space stations in theApollo Applications Project (AAP). The only AAP project funded wasSkylab (the first American space station)—which used existing spacecraft and hardware—thereby eliminating the need for Big Gemini.
The constellation for which the project was named is commonly pronounced/ˈdʒɛmɪnaɪ/, the last syllable rhyming witheye. However, staff of the Manned Spacecraft Center, including the astronauts, tended to pronounce the name/ˈdʒɛmɪni/, rhyming withknee. NASA's public affairs office then issued a statement in 1965 declaring "Jeh'-mih-nee" the "official" pronunciation.[2]Gus Grissom, acting as Houstoncapsule communicator whenEd White performed his spacewalk onGemini 4, is heard on flight recordings pronouncing the spacecraft's call sign "Jeh-mih-nee 4", and the NASA pronunciation is used in the 2018 filmFirst Man.[2]
TheApollo program was conceived in early 1960 as a three-man spacecraft to followProject Mercury.Jim Chamberlin, the head of engineering at theSpace Task Group (STG), was assigned in February 1961 to start working on a bridge program between Mercury and Apollo.[3] He presented two initial versions of a two-man spacecraft, then designated Mercury Mark II, at a NASA retreat at Wallops Island in March 1961.[3] Scale models were shown in July 1961 at theMcDonnell Aircraft Corporation's offices in St. Louis.[3]
After Apollo was chartered to land men on the Moon byPresident John F. Kennedy on May 25, 1961, it became evident to NASA officials that a follow-on to the Mercury program was required to develop certain spaceflight capabilities in support of Apollo.NASA approved the two-man / two-vehicle program rechristened Project Gemini (Latin for "twins"), in reference tothe third constellation of the Zodiac with its twin starsCastor andPollux, on December 7, 1961.[3] McDonnell Aircraft was contracted to build it on December 22, 1961.[4] The program was publicly announced on January 3, 1962, with these major objectives:[5]
Chamberlin designed the Gemini capsule, which carried a crew of two. He was previously the chiefaerodynamicist onAvro Canada's CF-105 Arrow fighter interceptor program.[6] Chamberlin joined NASA along with 25 senior Avro engineers after cancellation of the Canadian Arrow program, and became head of the U.S. Space Task Group's engineering division in charge of Gemini.[6][7] The prime contractor was McDonnell Aircraft Corporation, which was also the prime contractor for theProject Mercury capsule.[8]
AstronautGus Grissom was heavily involved in the development and design of theGemini spacecraft. What other Mercury astronauts dubbed "Gusmobile" was so designed around Grissom's 5'6" body that, when NASA discovered in 1963 that 14 of 16 astronauts would not fit in the spacecraft, the interior had to be redesigned.[9] Grissom wrote in his posthumous 1968 bookGemini! that the realization ofProject Mercury's end and the unlikelihood of his having another flight in that program prompted him to focus all his efforts on the upcoming Gemini program.[10]
The Gemini program was managed by theManned Spacecraft Center, located inHouston, 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 6A.
Guenter Wendt was a McDonnell engineer who supervised launch preparations for both the Mercury and Gemini programs and would go on to do the same when the Apollo program launched crews. His team was responsible for completion of the complex pad close-out procedures just prior to spacecraft launch, and he was the last person the astronauts would see prior to closing the hatch. The astronauts appreciated his taking absolute authority over, and responsibility for, the condition of the spacecraft and developed a good-humored rapport with him.[11]
NASA selectedMcDonnell Aircraft, which had been the prime contractor for theProject Mercury capsule, in 1961 to build the Gemini capsule, the first of which was delivered in 1963. The spacecraft was 18 feet 5 inches (5.61 m) long and 10 feet (3.0 m) wide, with a launch weight varying from 7,100 to 8,350 pounds (3,220 to 3,790 kg).[12]
The Gemini crew capsule (referred to as the Reentry Module) was essentially an enlarged version of the Mercury capsule. Unlike Mercury, theretrorockets, electrical power, propulsion systems, oxygen, and water were located in a detachable Adapter Module behind the Reentry Module which would burn up on reentry. A major design improvement in Gemini was to locate all internal spacecraft systems in modular components, which could be independently tested and replaced when necessary, without removing or disturbing other already tested components.
Many components in the capsule itself were reachable through their own small access doors. Unlike Mercury, Gemini used completely solid-state electronics, and its modular design made it easy to repair.[13]
Gemini's emergencylaunch escape system did not use an escape tower powered by asolid-fuel rocket, but instead used aircraft-styleejection seats. The tower was heavy and complicated, and NASA engineers reasoned that they could do away with it as the Titan II'shypergolic propellants would burn immediately on contact. A Titan II booster explosion had a smaller blast effect and flame than on the cryogenically fueled Atlas and Saturn. Ejection seats were sufficient to separate the astronauts from a malfunctioning launch vehicle. At higher altitudes, where the ejection seats could not be used, the astronauts would return to Earth inside the spacecraft, which would separate from the launch vehicle.[14]
The main proponent of using ejection seats was Chamberlin, who had never liked the Mercury escape tower and wished to use a simpler alternative that would also reduce weight. He reviewed several films of Atlas and Titan II ICBM failures, which he used to estimate the approximate size of a fireball produced by an exploding launch vehicle and from this he gauged that the Titan II would produce a much smaller explosion, thus the spacecraft could get away with ejection seats.
Maxime Faget, the designer of the Mercury LES, was on the other hand less-than-enthusiastic about this setup. Aside from the possibility of the ejection seats seriously injuring the astronauts, they would also only be usable for about 40 seconds after liftoff, by which point the booster would be attaining Mach 1 speed and ejection would no longer be possible. He was also concerned about the astronauts being launched through the Titan's exhaust plume if they ejected in-flight and later added, "The best thing about Gemini was that they never had to make an escape."[15]
The Gemini ejection system was never tested with the Gemini cabin pressurized with pure oxygen, as it was prior to launch. In January 1967, the fatalApollo 1 fire demonstrated that pressurizing a spacecraft with pure oxygen created an extremely dangerous fire hazard.[16] In a 1997 oral history, astronautThomas P. Stafford commented on theGemini 6 launch abort in December 1965, when he and command pilotWally Schirra nearly ejected from the spacecraft:
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.[17]
Gemini was the first astronaut-carrying spacecraft to include an onboard computer, theGemini Guidance Computer, to facilitate management and control of mission maneuvers. This computer, sometimes called the Gemini Spacecraft On-Board Computer (OBC), was very similar to theSaturn Launch Vehicle Digital Computer. The Gemini Guidance Computer weighed 58.98 pounds (26.75 kg). Itscore memory had 4096addresses, each containing a 39-bitword composed of three 13-bit "syllables". All numeric data was26-bittwo's-complement integers (sometimes used asfixed-point numbers), either stored in the first two syllables of a word or in theaccumulator.Instructions (always with a 4-bitopcode and 9 bits of operand) could go in any syllable.[18][19][20][21]
Unlike Mercury, Gemini used in-flightradar and anartificial horizon, similar to those used in the aviation industry.[18] Like Mercury, Gemini used ajoystick to give the astronauts manual control ofyaw, pitch, and roll. Gemini added control of the spacecraft'stranslation (forward, backward, up, down, and sideways) with a pair of T-shaped handles (one for each crew member). Translation control enabledrendezvous and docking, and crew control of the flight path. The same controller types were also used in theApollo spacecraft.[9]
The original intention for Gemini was to land on solid ground instead of at sea, using aRogallo wing rather than a parachute, with the crew seated upright controlling the forward motion of the craft. To facilitate this, the airfoil did not attach just to the nose of the craft, but to an additional attachment point for balance near the heat shield. This cord was covered by a strip of metal which ran between the twin hatches.[22] This design was ultimately dropped, and parachutes were used to make a sea landing as in Mercury. The capsule was suspended at an angle closer to horizontal, so that a side of the heat shield contacted the water first. This eliminated the need for the landing bag cushion used in the Mercury capsule.
The adapter module in turn was separated into a Retro module and an Equipment module.
The Retro module contained four solid-fuel TE-M-385Star-13E retrorockets, each spherical in shape except for its rocket nozzle, which were structurally attached to two beams that reached across the diameter of the retro module, crossing at right angles in the center.[23] Re-entry began with the retrorockets firing one at a time. Abort procedures at certain periods during lift-off would cause them to fire at the same time, thrusting the Descent module away from the Titan rocket.
Gemini was equipped with anOrbit Attitude and Maneuvering System (OAMS), containing sixteen thrusters fortranslation control in all three perpendicular axes (forward/backward, left/right, up/down), in addition toattitude control (pitch, yaw, and roll angle orientation) as in Mercury. Translation control allowed changingorbital inclination and altitude, necessary to performspace rendezvous with other craft, anddocking with theAgena Target Vehicle (ATV), with its own rocket engine which could be used to perform greater orbit changes.
Early short-duration missions had their electrical power supplied by batteries; later endurance missions used the firstfuel cells in crewed spacecraft.
Gemini was in some regards more advanced than Apollo because the latter program began almost a year earlier. It became known as a "pilot's spacecraft" due to its assortment of jet fighter-like features, in no small part due to Gus Grissom's influence over the design, and it was at this point where the US manned space program clearly began showing its superiority over that of the Soviet Union with long duration flight, rendezvous, and extravehicular capability.[note 4] The Soviet Union during this period was developing theSoyuz spacecraft intended to take cosmonauts to the Moon, but political and technical problems began to get in the way, leading to the ultimate end of their crewed lunar program.
TheTitan II debuted in 1962 as the Air Force's second-generation ICBM to replace the Atlas. By using hypergolic fuels, it could be stored longer and be easily readied for launch in addition to being a simpler design with fewer components. The only caveat was the propellant mix (nitrogen tetroxide andhydrazine) were extremely toxic compared to the Atlas' liquid oxygen/RP-1. However, the Titan had considerable difficulty being man-rated due to early problems withpogo oscillation. The launch vehicle used a radio guidance system that was unique to launches from Cape Kennedy.
Deke Slayton, as director of flight crew operations, had primary responsibility for assigning crews for the Gemini program. Each flight had a primary crew and backup crew, and the backup crew would rotate to primary crew status three flights later. Slayton intended for first choice of mission commands to be given to the four remaining active astronauts of theMercury Seven:Alan Shepard, Grissom, Cooper, and Schirra. (John Glenn had retired from NASA in January 1964 andScott Carpenter, who was blamed by some in NASA management for the problematic reentry ofAurora 7, was on leave to participate in the Navy'sSEALAB project and was grounded from flight in July 1964 due to an arm injury sustained in a motorbike accident. Slayton himself continued to be grounded due to a heart problem.) As for Shepard, during training on the Gemini Project, his inner ear deficiency due toMenière's Disease would effectively ground him as well and keep him removed from the flight roster until he underwent corrective surgery and would not fly on Gemini at all, but return to flight withApollo 14 as Commander.
Titles used for the left-hand (command) and right-hand (pilot) seat crew positions were taken from theU.S. Air Force pilot ratings,Command Pilot andPilot. Sixteen astronauts flew on 10 crewed Gemini missions:
| Group | Astronaut | Service | Mission, prime crew position | Mission, backup crew position |
|---|---|---|---|---|
| Astronaut Group 1 | Gordon Cooper | USAF | Gemini 5 Command Pilot | Gemini 12 Command Pilot |
| Virgil "Gus" Grissom | Gemini 3 Command Pilot | Gemini 6A Command Pilot | ||
| Walter M. Schirra | USN | Gemini 6A Command Pilot | Gemini 3 Command Pilot | |
| Astronaut Group 2 | Neil Armstrong | Civilian[note 5] | Gemini 8 Command Pilot | Gemini 5 Command Pilot |
| Gemini 11 Command Pilot | ||||
| Frank Borman | USAF | Gemini 7 Command Pilot | Gemini 4 Command Pilot | |
| Charles "Pete" Conrad | USN | Gemini 5 Pilot | Gemini 8 Command Pilot | |
| Gemini 11 Command Pilot | ||||
| Jim Lovell | USN | Gemini 7 Pilot | Gemini 4 Pilot | |
| Gemini 12 Command Pilot | Gemini 9A Command Pilot | |||
| James McDivitt | USAF | Gemini 4 Command Pilot | — | |
| Thomas P. Stafford | Gemini 6A Pilot | Gemini 3 Pilot[note 6] | ||
| Gemini 9A Command Pilot | ||||
| Ed White | Gemini 4 Pilot | Gemini 7 Command Pilot | ||
| John Young | USN | Gemini 3 Pilot | Gemini 6A Pilot | |
| Gemini 10 Command Pilot | ||||
| Astronaut Group 3 | Edwin "Buzz" Aldrin | USAF | Gemini 12 Pilot | Gemini 9A Pilot |
| Eugene Cernan | USN | Gemini 9A Pilot | Gemini 12 Pilot | |
| Michael Collins | USAF | Gemini 10 Pilot | Gemini 7 Pilot | |
| Richard F. Gordon | USN | Gemini 11 Pilot | Gemini 8 Pilot | |
| David Scott | USAF | Gemini 8 Pilot | — | |
| Astronauts selected but did not fly | ||||
| Astronaut Group 1 | Alan Shepard | USN | Gemini 3 Command Pilot[note 7] | — |
| Astronaut Group 2 | Elliot See | Civilian[note 8] | Gemini 9 Command Pilot[note 9] | Gemini 5 Pilot |
| Astronaut Group 3 | William Anders | USAF | — | Gemini 11 Pilot |
| Charles Bassett | Gemini 9 Pilot[note 9] | — | ||
| Alan Bean | USN | — | Gemini 10 Command Pilot | |
| Clifton Williams | USMC | — | Gemini 10 Pilot | |
In late 1963, Slayton selected Shepard and Stafford for Gemini 3, McDivitt and White for Gemini 4, and Schirra and Young for Gemini 5 (which was to be the first Agena rendezvous mission). The backup crew for Gemini 3 was Grissom and Borman, who were also slated forGemini 6, to be the first long-duration mission. Finally Conrad and Lovell were assigned as the backup crew forGemini 4.
Delays in the production of the Agena Target Vehicle caused the first rearrangement of the crew rotation. The Schirra and Young mission was bumped to Gemini 6 and they became the backup crew for Shepard and Stafford. Grissom and Borman then had their long-duration mission assigned to Gemini 5.
The second rearrangement occurred when Shepard developedMénière's disease, an inner ear problem. Grissom was then moved to command Gemini 3. Slayton felt that Young was a better personality match with Grissom and switched Stafford and Young. Finally, Slayton tapped Cooper to command the long-duration Gemini 5. Again for reasons of compatibility, he moved Conrad from backup commander of Gemini 4 to pilot of Gemini 5, and Borman to backup command of Gemini 4. Finally he assigned Armstrong andElliot See to be the backup crew for Gemini 5.The third rearrangement of crew assignment occurred when Slayton felt that See wasn't up to the physical demands of EVA on Gemini 8. He reassigned See to be the prime commander of Gemini 9 and put Scott as pilot of Gemini 8 andCharles Bassett as the pilot of Gemini 9.
The fourth and final rearrangement of the Gemini crew assignment occurred after the deaths of See and Bassett when their trainer jet crashed, coincidentally into a McDonnell building which held their Gemini 9 capsule in St. Louis. The backup crew of Stafford and Cernan was then moved up to the new prime crew of Gemini 9A. Lovell and Aldrin were moved from being the backup crew of Gemini 10 to be the backup crew of Gemini 9. This cleared the way through the crew rotation for Lovell and Aldrin to become the prime crew of Gemini 12.
Along with the deaths of Grissom, White, andRoger Chaffee in the fire ofApollo 1, this final arrangement helped determine the makeup of the first seven Apollo crews, and who would be in position for a chance to be the first to walk on the Moon.
In April 1964 and January 1965, two Gemini missions were flown without crews to test systems and the heat shield. These were followed by 10 flights with crews in 1965 and 1966. All were launched by Titan II launch vehicles. Some highlights from the Gemini program:
Rendezvous in orbit is not a straightforward maneuver. Should a spacecraft increase its speed to catch up with another, the result is that it goes into a higher and slower orbit and the distance thereby increases. The right procedure is to go to a lower orbit first, which increases relative speed, and then approach the target spacecraft from below and decrease orbital speed to meet it.[24] To practice these maneuvers, special rendezvous and docking simulators were built for the astronauts.[25]
| Mission | LV serial No | Spacecraft Nº | Command Pilot | Pilot | Mission dates | Launch time | Duration |
|---|---|---|---|---|---|---|---|
| Gemini 1 | GLV-1 12556 | SC1 | Uncrewed | Uncrewed | 8–12 April 1964 | 16:00UTC | 03d 23h1 |
| First test flight of Gemini; spacecraft was intentionally destroyed during re-entry 1: The mission duration was 4h 50m, sufficient to achieve all of the mission aims in three orbits; the spacecraft remained in orbit for 3d 23h. | |||||||
| Gemini 2 | GLV-2 12557 | SC2 | Uncrewed | Uncrewed | 19 January 1965 | 14:04 UTC | 00d 00h 18m 16s |
| Suborbital flight to test heat shield | |||||||
Gemini 3 | GLV-3 12558 | SC3 | Grissom | Young | 23 March 1965 | 14:24 UTC | 00d 04h 52m 31s |
| First crewed Gemini flight, three orbits. | |||||||
Gemini IV | GLV-4 12559 | SC4 | McDivitt | White | 3–7 June 1965 | 15:16 UTC | 04d 01h 56m 12s |
| Included firstextravehicular activity (EVA) by an American; White's "space walk" was a 22-minute EVA exercise. | |||||||
Gemini V | GLV-5 12560 | SC5 | Cooper | Conrad | 21–29 August 1965 | 14:00 UTC | 07d 22h 55m 14s |
| First week-long flight; first use of fuel cells for electrical power; evaluated guidance and navigation system for future rendezvous missions. Completed 120 orbits. | |||||||
Gemini VII | GLV-7 12562 | SC7 | Borman | Lovell | 4–18 December 1965 | 19:30 UTC | 13d 18h 35m 01s |
| When the original Gemini VI mission was scrubbed because the launch of the Agena docking target failed, Gemini VII was used as the rendezvous target instead. Primary objective was to determine whether humans could live in space for 14 days. Completed 206 orbits. | |||||||
Gemini VI-A | GLV-6 12561 | SC6 | Schirra | Stafford | 15–16 December 1965 | 13:37 UTC | 01d 01h 51m 24s |
| Rescheduled from October to rendezvous with Gemini VII after the original Agena Target Vehicle launch failed. First space rendezvous accomplished, station-keeping for over five hours at distances from 1 to 300 feet (0.30 to 91 m). First musical instruments played in space; crew played "Jingle Bells" on a harmonica and a ring of small bells as part of a jocularSanta Claus sighting.[26][27] | |||||||
Gemini VIII | GLV-8 12563 | SC8 | Armstrong | Scott | 16–17 March 1966 | 16:41 UTC | 00d 10h 41m 26s |
| Accomplished first docking with another space vehicle, an uncrewed Agena Target Vehicle. While docked, a Gemini spacecraft thruster malfunction caused near-fatal tumbling of the craft, which, after undocking, Armstrong was able to overcome; the crew effected the first emergency landing of a crewed U.S. space mission. | |||||||
Gemini IX-A | GLV-9 12564 | SC9 | Stafford | Cernan | 3–6 June 1966 | 13:39 UTC | 03d 00h 20m 50s |
| Rescheduled from May to rendezvous and dock with theAugmented Target Docking Adapter (ATDA) after the original Agena Target Vehicle launch failed. The ATDA shroud did not completely separate, making docking impossible (right). Three different types of rendezvous, two hours of EVA, and 44 orbits were completed. |  | ||||||
Gemini X | GLV-10 12565 | SC10 | Young | Collins | 18–21 July 1966 | 22:20 UTC | 02d 22h 46m 39s |
| First use of the Agena Target Vehicle's propulsion systems. The spacecraft also rendezvoused with the Agena Target Vehicle from Gemini VIII. Collins had 49 minutes of EVA standing in the hatch and 39 minutes of EVA to retrieve experiments from the Agena. 43 orbits completed. | |||||||
Gemini XI | GLV-11 12566 | SC11 | Conrad | Gordon | 12–15 September 1966 | 14:42 UTC | 02d 23h 17m 09s |
| Gemini record altitude withapogee of 739.2 nautical miles (1,369.0 km)[28] reached using the Agena Target Vehicle propulsion system after first orbit rendezvous and docking. Gordon made a 33-minute EVA and two-hour standup EVA. 44 orbits. | |||||||
Gemini XII | GLV-12 12567 | SC12 | Lovell | Aldrin | 11–15 November 1966 | 20:46 UTC | 03d 22h 34m 31s |
| Final Gemini flight. Rendezvoused and docked manually with the target Agena and kept station with it during EVA. Aldrin set an EVA record of 5 hours and 30 minutes for one space walk and two stand-up exercises, and demonstrated solutions to previous EVA problems. 59 orbits completed | |||||||
TheGemini-Titan II launch vehicle was adapted by NASA from the U.S. Air ForceTitan II ICBM. (Similarly, theMercury-Atlas launch vehicle had been adapted from the USAFAtlas missile.) The Gemini-Titan II rockets were assigned Air Force serial numbers, which were painted in four places on each Titan II (on opposite sides on each of the first and second stages). USAF crews maintained Launch Complex 19 and prepared and launched all of the Gemini-Titan II launch vehicles. Data and experience operating the Titans was of value to both the U.S. Air Force and NASA.
The USAF serial numbers assigned to the Gemini-Titan launch vehicles are given in the tables above. Fifteen Titan IIs were ordered in 1962 so the serial is "62-12XXX", but only "12XXX" is painted on the Titan II. The order for the last three of the 15 launch vehicles was canceled on July 30, 1964, and they were never built. Serial numbers were, however, assigned to them prospectively:12568 - GLV-13;12569 - GLV-14; and12570 - GLV-15.
From 1962 to 1967, Gemini cost $1.3 billion in 1967 dollars ($9.07 billion in 2023[29]).[1] In January 1969, a NASA report to the US Congress estimating the costs for Mercury, Gemini, and Apollo (through the first crewed Moon landing) included $1.2834 billion for Gemini: $797.4 million for spacecraft, $409.8 million for launch vehicles, and $76.2 million for support.[30]
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A number of detailed Gemini models and mockups are on display:[51]
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McDonnell Aircraft, the main contractor for Mercury and Gemini, was also one of the original bidders on the prime contract for Apollo, but lost out toNorth American Aviation. McDonnell later sought to extend the Gemini program by proposing a derivative which could be used to fly acislunar mission and even achieve a crewed lunar landing earlier and at less cost than Apollo, but these proposals were rejected by NASA.
A range of applications were considered for Advanced Gemini missions, including military flights, space station crew and logistics delivery, and lunar flights. The Lunar proposals ranged from reusing the docking systems developed for the Agena Target Vehicle on more powerful upper stages such as the Centaur, which could propel the spacecraft to the Moon, to complete modifications of the Gemini to enable it to land on the lunar surface. Its applications would have ranged from crewed lunar flybys before Apollo was ready, to providing emergency shelters or rescue for stranded Apollo crews, or even replacing the Apollo program.
Some of the Advanced Gemini proposals used "off-the-shelf" Gemini spacecraft, unmodified from the original program, while others featured modifications to allow the spacecraft to carry more personnel, dock with space stations, visit the Moon, and perform other mission objectives. Other modifications considered included the addition of wings or a parasail to the spacecraft, in order to enable it to make a horizontal landing.
Big Gemini (or "Big G") was another proposal by McDonnell Douglas made in August 1969. It was intended to provide large-capacity, all-purpose access to space, including missions that ultimately used Apollo or the Space Shuttle.
The study was performed to generate a preliminary definition of a logistic spacecraft derived from Gemini that would be used to resupply an orbiting space station. Land-landing at a preselected site and refurbishment and reuse were design requirements. Two baseline spacecraft were defined: a nine-man minimum modification version of the Gemini B called Min-Mod Big G and a 12-man advanced concept, having the same exterior geometry but with new, state-of-the-art subsystems, called Advanced Big G.[52] Three launch vehicles-Saturn IB,Titan IIIM, andSaturn INT-20 (S-IC/S-IVB) were investigated for use with the spacecraft.
The Air Force had an interest in the Gemini system, and decided to use its own modification of the spacecraft as the crew vehicle for theManned Orbital Laboratory. To this end, the Gemini 2 spacecraft was refurbished and flown again atop a mockup of the MOL, sent into space by aTitan IIIC. This was the first time a spacecraft went into space twice.
The USAF also thought of adapting the Gemini spacecraft for military applications, such as crude observation of the ground (no specialized reconnaissance camera could be carried) and practicing making rendezvous with suspicious satellites. This project was calledBlue Gemini. The USAF 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 airfoil and land on three skids, carried over 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 Gemini by itself. Blue Gemini was canceled in 1963 bySecretary of DefenseRobert McNamara, who decided the NASA Gemini flights could conduct necessary military experiments. MOL was canceled by Secretary of DefenseMelvin Laird in 1969, when it was determined that uncrewedspy satellites could perform the same functions much more cost-effectively.
This article incorporatespublic domain material from websites or documents of theNational Aeronautics and Space Administration.
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