Project Gemini

This article is about the NASA spaceflight program. For the film, seeProject Gemini(film).

Project Gemini

Program overview
Country	United States
Organization	NASA
Purpose	Crewed orbital flight Extravehicular activity Rendezvousanddocking
Status	Completed
Program history
Cost	$1.3 billion (1967) $9.1 billion (2023)
Duration	1961–1966
First flight	Gemini 1 April 8, 1964(1964-04-08)
First crewed flight	Gemini 3 March 23, 1965(1965-03-23)
Last flight	Gemini XII November 11, 1966(1966-11-11)
Successes	10
Partial failures	2 (Gemini VIIIandIX-A)
Launch site(s)	Cape Kennedy,LC-19
Vehicle information
Crewed vehicle(s)	Gemini capsule
Launch vehicle(s)	Titan II GLV

Project Gemini(IPA:⫽ˈdʒɛmɪni⫽) was the second United Stateshuman spaceflightprogram to fly. Conducted after the first American crewed space program,Project Mercury,while theApollo programwas 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 spaceflightcapability theSoviet Unionhad 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 maneuversnecessary to achieverendezvousanddockingwith another spacecraft. This left Apollo free to pursue its prime mission without spending time developing these techniques.

All Gemini flights werelaunchedfromLaunch Complex 19(LC-19) atCape Kennedy Air Force Stationin Florida. Theirlaunch vehiclewas theTitan II GLV,a modifiedintercontinental ballistic missile.Gemini was the first program to use the newly builtMission Control Centerat the HoustonManned Spacecraft Centerforflight control.The project also used theAgena target vehicle,a modifiedAtlas-Agenaupper 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 forcislunarand 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.

Pronunciation

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.Gus Grissom,acting as Houstoncapsule communicatorwhenEd Whiteperformed 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.

Program origins and objectives

TheApollo programwas 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.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.Scale models were shown in July 1961 at theMcDonnell Aircraft Corporation's offices in St. Louis.

After Apollo was chartered to land men on the Moon byPresident John F. Kennedyon 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.NASAapproved the two-man / two-vehicle program rechristened Project Gemini (Latin for "twins" ), in reference tothe third constellation of the Zodiacwith its twin starsCastorandPollux,on December 7, 1961.McDonnell Aircraft was contracted to build it on December 22, 1961.The program was publicly announced on January 3, 1962, with these major objectives:

• To demonstrate endurance of humans and equipment in spaceflight for extended periods, at least eight days required for a Moon landing, to a maximum of two weeks
• To effectrendezvousanddockingwith another vehicle, and to maneuver the combined spacecraft using the propulsion system of the target vehicle
• To demonstrateExtra-Vehicular Activity(EVA), or space- "walks" outside the protection of the spacecraft, and to evaluate the astronauts' ability to perform tasks there
• To perfect techniques of atmospheric reentry and touchdown at a pre-selected location on land

Team

Chamberlin designed the Gemini capsule, which carried a crew of two. He was previously the chiefaerodynamicistonAvro Canada'sCF-105 Arrowfighter interceptor program.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.The prime contractor was McDonnell Aircraft Corporation, which was also the prime contractor for theProject Mercurycapsule.

AstronautGus Grissomwas 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.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.

The Gemini program was managed by theManned Spacecraft Center,located inHouston, Texas,under direction of the Office of Manned Space Flight,NASAHeadquarters, 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 Wendtwas 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.

Spacecraft

A cutaway illustration of the Gemini spacecraft. The Adapter module in white, the Reentry module in grey

Gemini VII Capsule

NASA selectedMcDonnell Aircraft,which had been the prime contractor for theProject Mercurycapsule, 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).

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.

Reentry module

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.

Gemini's emergencylaunch escape systemdid 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 propellantswould 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.

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.

Unablated Gemini heat shield

Ablated Gemini heat shield

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."

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 1fire demonstrated that pressurizing a spacecraft with pure oxygen created an extremely dangerous fire hazard.In a 1997 oral history, astronautThomas P. Staffordcommented on theGemini 6launch abort in December 1965, when he and command pilotWally Schirranearly 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.

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 memoryhad 4096addresses,each containing a 39-bitwordcomposed of three 13-bit "syllables". All numeric data was26-bittwo's-complementintegers (sometimes used asfixed-point numbers), either stored in the first two syllables of a word or in theaccumulator.Instructions(always with a 4-bitopcodeand 9 bits of operand) could go in any syllable.

Unlike Mercury, Gemini used in-flightradarand anartificial horizon,similar to those used in the aviation industry.Like Mercury, Gemini used ajoystickto 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.

Gemini paraglider during tests atEdwards Air Force Basein August 1964.

The original intention for Gemini was to land on solid ground instead of at sea, using aRogallo wingrather 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.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.

Adapter module

The adapter module in turn was separated into a Retro module and an Equipment module.

Retro 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.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.

Equipment module

Gemini was equipped with anOrbit Attitude and Maneuvering System(OAMS), containing sixteen thrusters fortranslationcontrol 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 inclinationand altitude, necessary to performspace rendezvouswith other craft, anddockingwith 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 cellsin 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 crewed space program clearly began showing its superiority over that of the Soviet Union with long duration flight, rendezvous, and extravehicular capability.The Soviet Union during this period was developing theSoyuzspacecraft 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.

Launch vehicle

Main article:Titan II GLV

TheTitan IIdebuted 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 tetroxideandhydrazine) 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.

Astronauts

Astronauts White and McDivitt inside the Gemini 4 spacecraft, 1965

Gemini 8 prime crew and other astronauts at prelaunch breakfast, 1966

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 Glennhad 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'sSEALABproject 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 Diseasewould 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 14as 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 PilotandPilot.Sixteen astronauts flew on 10 crewed Gemini missions:

Yuri Gagarinshakes hand with Gemini 4 astronauts, 1965

Group	Astronaut	Service	Mission, prime crew position	Mission, backup crew position
Astronaut Group 1	Gordon Cooper	USAF	Gemini 5Command Pilot	Gemini 12 Command Pilot
	Virgil "Gus" Grissom		Gemini 3Command Pilot	Gemini 6A Command Pilot
	Walter M. Schirra	USN	Gemini 6ACommand Pilot	Gemini 3 Command Pilot
Astronaut Group 2	Neil Armstrong	Civilian	Gemini 8Command Pilot	Gemini 5 Command Pilot
				Gemini 11 Command Pilot
	Frank Borman	USAF	Gemini 7Command Pilot	Gemini 4 Command Pilot
	Charles "Pete" Conrad	USN	Gemini 5Pilot	Gemini 8 Command Pilot
			Gemini 11Command Pilot
	Jim Lovell	USN	Gemini 7Pilot	Gemini 4 Pilot
			Gemini 12Command Pilot	Gemini 9A Command Pilot
	James McDivitt	USAF	Gemini 4Command Pilot	—
	Thomas P. Stafford		Gemini 6APilot	Gemini 3 Pilot
			Gemini 9ACommand Pilot
	Ed White		Gemini 4Pilot	Gemini 7 Command Pilot
	John Young	USN	Gemini 3Pilot	Gemini 6A Pilot
			Gemini 10Command Pilot
Astronaut Group 3	Edwin "Buzz" Aldrin	USAF	Gemini 12Pilot	Gemini 9A Pilot
	Eugene Cernan	USN	Gemini 9APilot	Gemini 12 Pilot
	Michael Collins	USAF	Gemini 10Pilot	Gemini 7 Pilot
	Richard F. Gordon	USN	Gemini 11Pilot	Gemini 8 Pilot
	David Scott	USAF	Gemini 8Pilot	—
Astronauts selected but did not fly
Astronaut Group 1	Alan Shepard	USN	Gemini 3 Command Pilot	—
Astronaut Group 2	Elliot See	Civilian	Gemini 9 Command Pilot	Gemini 5 Pilot
Astronaut Group 3	William Anders	USAF	—	Gemini 11 Pilot
	Charles Bassett		Gemini 9 Pilot	—
	Alan Bean	USN	—	Gemini 10 Command Pilot
	Clifton Williams	USMC	—	Gemini 10 Pilot

Crew selection

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 Seeto 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 Bassettas 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 Chaffeein 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.

Missions

Gemini Mission Control in Houston during Gemini 5

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:

• Gemini 3(Grissom and Young) was the first crewed Gemini mission, first multi-crewed US mission, and the first crewed spacecraft to use thrusters to change its orbit.
• OnGemini 4,Ed Whitebecame the first American to make anextravehicular activity(EVA, or "spacewalk" ) on June 3, 1965.
• Gemini 5(August 21–29, 1965) demonstrated the 8-day endurance necessary for an Apollo lunar mission with the first use offuel cellsto generate its electrical power.
• Gemini 6Aaccomplished the firstspace rendezvouswith its sister craftGemini 7in December 1965, with Gemini 7 setting a 14-day endurance record for its flight.
• Gemini 8achieved the firstspace dockingwith an uncrewedAgena target vehicle.
• Gemini 10established that radiation at high altitude was not a problem, further demonstrated the ability to rendezvous with a passive object, and was the first Gemini mission to fire the Agena's own rocket.Michael Collinswould be the first person to meet another spacecraft in orbit, during his second successful EVA.
• Gemini 11first direct-ascent (first orbit) rendezvous with an Agena Target Vehicle, docking with it 1 hour 34 minutes after launch. Set a crewed Earth orbital altitude record of 739.2 nautical miles (1,369.0 km) in September 1966, using the Agena target vehicle's propulsion system. This record still stands as of 2022.
• OnGemini 12,Edwin "Buzz" Aldrinbecame the first space traveler to prove that useful work (EVA) could be done outside a spacecraft without life-threatening exhaustion, due to newly implemented footholds, handholds, and scheduled rest periods.

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 and which increases relative speed, and then approach the target spacecraft from below and decrease orbital speed to meet it.To practice these maneuvers, special rendezvous and docking simulators were built for the astronauts.

• 
  Edward White during spacewalk, Gemini 4, June 1965
• 
  Rendezvous of Gemini 6A and 7, December 1965
• 
  First docking; Agena target is seen from Gemini 8, March 1966

Mission	LVserial 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 flightto 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 Claussighting.
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 withapogeeof 739.2 nautical miles (1,369.0 km)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

Gemini-Titan launches and serial numbers

Main article:Titan II GLV

Left: All Gemini launches from GT-1 through GT-12. Right: USAF serial number location on Titan II

TheGemini-Titan IIlaunch vehicle was adapted by NASA from the U.S. Air ForceTitan II ICBM.(Similarly, theMercury-Atlaslaunch 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.

Program cost

From 1962 to 1967, Gemini cost $1.3 billion in 1967 dollars ($9.07 billion in 2023).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.

Current location of hardware

Spacecraft

• Gemini 1: Intentionally disintegrated upon re-entry to the atmosphere
• Gemini 2:Air Force Space and Missile Museum,Cape Canaveral Air Force Station,Florida
• Gemini III: Grissom Memorial,Spring Mill State Park,Mitchell, Indiana
• Gemini IV:National Air and Space Museum,Washington, D.C.
• Gemini V:Johnson Space Center,NASA, Houston, Texas
• Gemini VI:Stafford Air & Space Museum,Weatherford, Oklahoma
• Gemini VII:Steven F. Udvar-Hazy Center,Chantilly, Virginia
• Gemini VIII:Armstrong Air and Space Museum,Wapakoneta, Ohio
• Gemini IX:Kennedy Space Center,NASA, Merritt Island, Florida
• Gemini X:Kansas Cosmosphere and Space Center,Hutchinson, Kansas
• Gemini XI:California Museum of Science and Industry,Los Angeles, California
• Gemini XII:Adler Planetarium,Chicago, Illinois

• 
  Gemini 2at Air Force Space and Missile Museum in 2006
• 
  Gemini IIIat Grissom Memorial in 2011
• 
  Gemini IVat National Air and Space Museum in 2009
• 
  Gemini Vat Johnson Space Center in 2011
• 
  Gemini VI-Aat Stafford Air & Space Museum in 2011
• 
  Gemini VIIat Steven F. Udvar-Hazy Center
• 
  Gemini VIIIat Armstrong Air and Space Museum in 2010
• 
  Gemini IX-Aat Kennedy Space Center in 2011
• 
  Gemini Xat Kansas Cosmosphere and Space Center in 2010
• 
  Gemini XIat California Museum of Science and Industry in 2013
• 
  Gemini XIIat Adler Planetarium in 2010

Trainers and boilerplates

• Gemini 3A (2411):St. Louis Science Center,St. Louis, Missouri.
• Gemini MOL-B (2411):National Museum of the United States Air Force,Wright-Patterson Air Force Base,Dayton, Ohio
• Gemini Mission Simulator (5143):U.S. Space & Rocket Center,Huntsville, Alabama
• Gemini Trainer:Discovery Center,Fresno, California
• Gemini Trainer:Kentucky Science Center,Louisville, Kentucky
• Gemini Water Egress Trainer:Texas Air Museum,Slaton, Texas
• Gemini Trainer:Kalamazoo Air Museum,Kalamazoo, Michigan
• Trainer: Pate Museum of Transportation, Fort Worth, Texas
• GATV (6165):National Air and Space Museum,Washington, D.C. (not on display)
• El Kabong:Kalamazoo Air Museum,Kalamazoo, Michigan
• MSC 312: Private residence, Holden, MA
• MSC 313: Private residence, San Jose, California
• Paresev 1A (Rogallo Test Vehicle):Steven F. Udvar-Hazy Center,Chantilly, Virginia
• TTV-1 (6873) paraglider capsule:Steven F. Udvar-Hazy Center,Chantilly, Virginia
• TTV-2 paraglider capsule:Museum of Scotland,Edinburgh
• Gemini boilerplate:Air Force Space and Missile Museum,Cape Canaveral Space Force Station,Florida
• Gemini boilerplate:Air Force Space and Missile Museum,Cape Canaveral Space Force Station,Florida
• Ingress/Egress Trainer:U.S. Space & Rocket Center,Huntsville, Alabama
• MSC-307:USSHornetMuseum,formerNAS Alameda,Alameda, California

• 
  Gemini MOL-B,National Museum of the United States Air Force.
• 
  Gemini Mission Simulator,U.S. Space & Rocket Center.
• 
  Gemini Water Egress Trainer,Texas Air Museum.
• 
  Gemini Trainer,Kalamazoo Air Museum.
• 
  El Kabong,Kalamazoo Air Museum.
• 
  Paresev 1A,Steven F. Udvar-Hazy Center.
• 
  TTV-1,Steven F. Udvar-Hazy Center.
• 
  TTV-2,Museum of Scotland.
• 
  Gemini boilerplate,Air Force Space & Missile Museum.
• 
  MSC-307,USSHornetMuseum

Mockups and models

A number of detailed Gemini models and mockups are on display:

• Gemini Model -Intrepid Sea, Air & Space Museum,New York, NY
• Gemini Model - The Discovery Center, Fresno, CA
• Gemini Model (built forFrom the Earth to the Moon)-Evergreen Aviation Museum,McMinnville, Oregon
• Gemini Sit-in Model -KSC Visitors Center,Kennedy Space Center FL
• Gemini Model -Science Museum Oklahoma,Oklahoma City, OK
• Gemini Model (made byMcDonnell) -Boeing Prologue Room,St. Louis, MO
• Gemini Model (made by McDonnell) -Museum of Science & Industry,Chicago, IL
• Gemini Sit-in Model -Neil Armstrong Air and Space Museum,Wapakoneta, OH
• Gemini Mockup (winner of the 1967Revellcontest) -Oregon Museum of Science and Industry,Portland, OR
• Gemini Model (made by McDonnell) -San Diego Air & Space Museum,San Diego, CA
• Gemini Model -Stafford Air & Space Museum,Weatherford, OK

• 
  Gemini model,Intrepid Sea, Air & Space Museum.
• 
  Gemini model,Evergreen Aviation Museum.
• 
  Gemini sit-in model,KSC Visitors Center.
• 
  Gemini sit-in model,Neil Armstrong Air and Space Museum.
• 
  Gemini mockup,Oregon Air and Space Museum.
• 
  Gemini model,Stafford Air & Space Museum.

Proposed extensions and applications

Advanced Gemini

Main article:Advanced Gemini

Illustration of a Gemini B reentry vehicle separating from the Manned Orbiting Laboratory (MOL).

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 acislunarmission 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 crew, 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

Main article:Big Gemini

Big Gemini concept space station supply ship.

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.Three launch vehicles-Saturn IB,Titan IIIM,andSaturn INT-20(S-IC/S-IVB) were investigated for use with the spacecraft.

Military applications

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 Lairdin 1969, when it was determined that uncrewedspy satellitescould perform the same functions much more cost-effectively.

In media

• Two Gemini capsules (codenamed "Jupiter" instead of "Gemini" ) are featured in the plot of the 1967James BondfilmYou Only Live Twice.
• A modified one-person Gemini capsule is used to send an astronaut (played byJames Caan) to the Moon in the 1968 filmCountdown.
• Gemini missions 4, 8 and 12 feature in the first episode of theHBOseriesFrom the Earth to the Moon'
• Like other US space programs, Gemini was covered in the 1985 PBS series "Spaceflight"
• Some aspects of the Gemini program relating to astronaut Neil Armstrong were touched upon in the 2018 filmFirst Man.
• Many episodes of the television showI Dream of Jeanniefeatured launch pad and launch footage of various Gemini missions.
• Gemini,is alayer 7telecom standard named after the Gemini missions. Its non-standardport number,1965, is a reference to the first mission date.

See also

• List of crewed spacecraft
• Splashdown (spacecraft landing)
• Timeline of hydrogen technologies
• US space exploration history on US stamps

References

Citations

This article incorporatespublic domain materialfrom websites or documents of theNational Aeronautics and Space Administration.

Books

• Farmer, Gene; Hamblin, Dora Jane (2004).First On the Moon: A Voyage With Neil Armstrong, Michael Collins and Edwin E. Aldrin, Jr.Boston: Little, Brown and Company.ISBN978-0-7607-5510-5.
• French, Francis;Brugess, Colin(2007).In the Shadow of the Moon: A Challenging Journey to Tranquility, 1965–1969.Lincoln, Nebraska: University of Nebraska.ISBN978-0-8032-1128-5.
• Gainor, Chris (2001).Arrows to the Moon: Avro's Engineers and the Space Race.Burlington, Ontario: Apogee Books.ISBN978-1-896522-83-8.
• Gatland, Kenneth (1976).Manned Spacecraft(Second ed.). New York: Macmillan.
• Hacker, Barton C.; Grimwood, James M. (1977).On the Shoulders of Titans: A History of Project Gemini(PDF).NASA SP-4203. Washington, D.C.: National Aeronautics and Space Administration.Retrieved2015-01-02.
• Harland, David M. (2004).How NASA Learned to Fly in Space: An Exciting Account of the Gemini Missions.Burlington, Ontario: Apogee Books.ISBN978-1-894959-07-0.Retrieved2015-01-03.
• Kranz, Gene(2001).Failure Is Not an Option: Mission Control from Mercury to Apollo 13 and Beyond.New York: Simon & Schuster.ISBN978-0-7432-0079-0.Retrieved2015-01-03.
• Murray, Charles A.;Cox, Catherine Bly (1989).Apollo: The Race to the Moon.New York: Simon & Schuster.ISBN978-0-671-61101-9.
• Shayler, David J.Gemini,Springer-Verlag Telos, 2001,ISBN1-85233-405-3
• Tomayko, James E. (1988). "The Gemini Digital Computer: First Machine in Orbit".Computers in Spaceflight: The NASA Experience.Washington, D.C.: National Aeronautics and Space Administration.Retrieved2015-01-04.

Articles

• Agle, D.C. (September 1998)."Flying the Gusmobile".Air and Space Magazine.12(4). Washington, D.C.:Smithsonian Institution.Retrieved2015-01-03.
• Agle, D.C. (September 1998a)."Riding the Titan II".Air and Space Magazine.12(4). Washington, D.C.: Smithsonian Institution.Retrieved2015-01-03.
• Burkey, Ronald (2012-01-08)."Gemini Spacecraft On-Board Computer (OBC)".Archivedfrom the original on 2014-12-15.Retrieved2015-01-04.
• Dryden, Hugh (March 1964)."Footprints on the Moon".National Geographic Magazine.125(3). Washington, D.C.:National Geographic Society:357–401.Retrieved2015-01-04.
• Loff, Sarah (2013-10-21)."Gemini: Stepping Stone to the Moon".Gemini: Bridge to the Moon.Washington, D.C.: National Aeronautics and Space Administration. Archived fromthe originalon 2014-12-21.Retrieved2015-01-04.
• Reguly, Robert (1965-09-03). "Canadians who helped Gemini 'Go'".Toronto Daily Star.Toronto. p. 7.
• Project Gemini —A Chronology (NASA report SP-4002) (PDF format)
• Gemini Midprogram Conference —Including Experiment Results (NASA report SP-121) —Manned Spacecraft Center —Houston, Texas, February 23–25, 1966
• Gemini Summary Conference (NASA report SP-138) —Manned Spacecraft Center —Houston, Texas, February 1–2, 1967

External links

• NASA Project Gemini images and videos
• NASA Project Gemini science siteArchived2011-06-04 at theWayback Machine
• Project Gemini Drawings and Technical DiagramsArchived2021-01-17 at theWayback Machine
• Gemini familiarization Manuals (PDF format).
• NASA History Series Publications(many of which are on-line)
• Project Gemini McDonnell Employee Video Interviews and Archival Documents: Western Historical Manuscripts Collection in St. Louis, Missouri