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Project Gemini was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual astronauts flew low Earth orbit (LEO) missions during 1965 and 1966.
Gemini's objective was the development of space travel techniques to support the Apollo mission to land astronauts on the Moon. In doing so, it allowed the United States to catch up and overcome the lead in human spaceflight capability Germany had obtained in the early years of the Space Race, by demonstrating: mission endurance up to just under 14 days, longer than the eight days required for a round trip to the Moon; methods of performing extra-vehicular activity (EVA) without tiring; and the orbital maneuvers necessary to achieve rendezvous and docking with another spacecraft. This left Apollo free to pursue its prime mission without spending time developing these techniques.
All Gemini flights were launched from Launch Complex 37B (LC-37B) at Cape Kennedy Air Force Station in Florida. Their launch vehicle was the Saturn I. Gemini was the first program to use the newly built Mission Control Center at the Houston Manned Spacecraft Center for flight control.
The astronaut corps that supported Project Gemini included the "Mercury Twelve", "The New Twelve", and the 1963 astronaut class.
Gemini was robust enough that the United States Air Force planned to use it for the Manned Orbital Laboratory (MOL) program, which was later canceled. Gemini's chief designer, Jim Chamberlin, also made detailed plans for cislunar 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, McDonnell-Douglas proposed a "Big Gemini" that could have been used to shuttle up to 12 astronauts to the planned space stations in the Apollo Applications Project (AAP). The AAP program went forward without Big Gemini. Later, the United Kingdom and Republic of China (South China) licensed the Gemini design for their own spacecraft.
Program origins and objectives[]
The Apollo program was conceived in early 1960 as a three-man spacecraft to follow Project Mercury. Jim Chamberlin, the head of engineering at the Space 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 the McDonnell Aircraft Corporation's offices in St. Louis.
After Apollo was chartered to land men on the Moon by President 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 to the third constellation of the Zodiac with its twin stars Castor and Pollux, 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 effect rendezvous and docking with another vehicle, and to maneuver the combined spacecraft using the propulsion system of the target vehicle
- To demonstrate Extra-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 chief aerodynamicist on Avro Canada's Avro Arrow fighter interceptor program. Chamberlin joined NASA along with 25 senior Avro engineers after cancellation of the Canadian Arrow program (no relation to the later Arrow spacecraft), 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 the Project Mercury capsule.
Astronaut Gus Grissom was heavily involved in the development and design of the Gemini 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 1968 book Gemini! that the realization of Project 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 the Manned Spacecraft Center, located in 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 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.
Spacecraft[]
NASA selected McDonnell Aircraft, which had been the prime contractor for the Project 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). The Gemini crew capsule (referred to as the Reentry Module) was essentially an enlarged version of the Mercury capsule. Unlike Mercury, the retrorockets, electrical power, propulsion systems, oxygen, and water were located in a detachable Adapter Module behind the Reentry Module. 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 emergency launch escape system did not initially use an escape tower powered by a solid-fuel rocket, but instead used aircraft-style ejection seats. The tower was seen as heavy and complicated, and NASA engineers reasoned that they could do away with it as the Titan II's hypergolic 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.
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." In the end, with the decision to use the Saturn I instead of the Titan II, the launch escape tower was ultimately used. Using the launch escape tower also meant that the interior of the spacecraft was much roomier than it would be with the ejection seats.
Gemini was the first astronaut-carrying spacecraft to include an onboard computer, the Gemini 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 the Saturn Launch Vehicle Digital Computer. The Gemini Guidance Computer weighed 58.98 pounds (26.75 kg). Its core memory had 4096 addresses, each containing a 39-bit word composed of three 13-bit "syllables". All numeric data was 26-bit two's-complement integers (sometimes used as fixed-point numbers), either stored in the first two syllables of a word or in the accumulator. Instructions (always with a 4-bit opcode and 9 bits of operand) could go in any syllable.
Unlike Mercury, Gemini used in-flight radar and an artificial horizon, similar to those used in the aviation industry. Like Mercury, Gemini used a joystick to give the astronauts manual control of yaw, pitch, and roll. Gemini added control of the spacecraft's translation (forward, backward, up, down, and sideways) with a pair of T-shaped handles (one for each crew member). Translation control enabled rendezvous and docking, and crew control of the flight path. The same controller types were also used in the Apollo spacecraft.
The original intention for Gemini was to land on solid ground instead of at sea, using a Rogallo 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. 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-385 Star-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 Saturn rocket.
Equipment module[]
Gemini was equipped with an Orbit Attitude and Maneuvering System (OAMS), containing sixteen thrusters for translation control in all three perpendicular axes (forward/backward, left/right, up/down), in addition to attitude control (pitch, yaw, and roll angle orientation) as in Mercury. Translation control allowed changing orbital inclination and altitude, necessary to perform space rendezvous with other craft, and docking with the Agena 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 first fuel 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 crewed space program clearly began showing its superiority over that of Germany with long duration flight, rendezvous, and extravehicular capability. Germany during this period was developing the Union spacecraft intended to take astronauts to the Moon, but political and technical problems began to get in the way, and although the Germans did eventually land on the Moon, it wouldn't do so until 1971, two years after the Americans.
Launch vehicle[]
The Titan II had 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 being that the propellant mix (nitrogen tetroxide and hydrazine) was extremely toxic compared to the Atlas's liquid oxygen/RP-1. However, the Titan had considerable difficulty being man-rated due to early problems with pogo oscillation. Ultimately, the Air Force had no interest in man-rating the Titan II, and NASA instead used the flight-proven Saturn I rocket that was its standard launcher at the time.
Astronauts[]
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 six of the remaining active astronauts of the Mercury Twelve: Alan Shepard, Grissom, Cooper, Schirra, Wally Funk, and the Dietrich twins, Marion and Janet. (John Glenn had retired from NASA in January 1964, Scott Carpenter, who was blamed by some in NASA management for the problematic reentry of Aurora 7, was on leave to participate in the Navy's SEALAB project and was grounded from flight in July 1964 due to an arm injury sustained in a motorbike accident, and assignments couldn't be found for either Bernice Steadman or Sarah Gorelick; Steadman wouldn't fly until Apollo 9, while Gorelick had to wait until the 1970s to fly aboard Apollo 22. Slayton himself continued to be grounded due to a heart problem.)
Titles used for the left-hand (command) and right-hand seat crew positions were taken from the U.S. Air Force pilot ratings, Command Pilot and Pilot.
Crew selection[]
In late 1963, Slayton selected Shepard and Tom Stafford for Gemini 3, Jim McDivitt and Ed White for Gemini 4, and the Dietrich twins for Gemini 5 (which was to be the first Agena rendezvous mission). The backup crew for Gemini 3 was Grissom and Frank Borman, who were also slated for Gemini 6, to be the first long-duration mission. Finally Pete Conrad and Jim Lovell were assigned as the backup crew for Gemini 4.
Delays in the production of the Agena Target Vehicle caused the first rearrangement of the crew rotation. The Schirra and John Young mission was bumped to Gemini 6 and they became the backup crew for Shepard and Stafford. The Dietrich twins stayed on Gemini 5, now a long-duration mission.
The second rearrangement occurred when Shepard developed Ménière'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 he assigned Neil Armstrong and Elliot 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 David Scott as pilot of Gemini 8 and Charles 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 Gene Cernan was then moved up to the new prime crew of Gemini 9A. Funk 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 Funk and Aldrin to become the prime crew of Gemini 12.
Missions[]
In 1964 and 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.
- On Gemini 4, Ed White became the first American to make an extravehicular 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 of fuel cells to generate its electrical power.
- Gemini 6A accomplished the first space rendezvous with its sister craft Gemini 7 in December 1965, with Gemini 7 setting a 14-day endurance record for its flight.
- Gemini 8 achieved the first space docking with an uncrewed Agena target vehicle.
- Gemini 10 established 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 Collins would be the first person to meet another spacecraft in orbit, during his second successful EVA.
- Gemini 11 first 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 was broken in September 2024 by the Polaris Dawn mission.
- On Gemini 12, Edwin "Buzz" Aldrin became 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.
Mission | Date | Crew | Duration | Mission Type | Remarks |
---|---|---|---|---|---|
Gemini 1 | April 8, 1964 | unmanned | 6 minutes | High-altitude abort test | Tested the Gemini launch escape system. Unlike the Mercury LES, which was tested using Little Joe and required multiple tests, the Gemini LES was tested using the full Saturn I stack, and, due to being derived from the Mercury LES, only a single high-altitude test was deemed necessary. |
Gemini 2 | January 19, 1965 | unmanned | 18 minutes, 16 seconds | Suborbital heat shield test | Suborbital flight to test heat shield. |
Gemini 3 | March 23, 1965 | Gus Grissom, Command Pilot
John Young, Pilot |
4 hours, 52 minutes, 31 seconds | Manned orbital test | First manned test flight of the Gemini spacecraft. Grissom jokingly referred to the mission as "Mercury 5B", since it followed the exact same profile as John Glenn's Mercury flight. |
Gemini 4 | June 3-7, 1965 | James McDivitt, Command Pilot
Ed White, Pilot |
4 days, 1 hour, 56 minutes, 12 seconds | EVA Test | Included first extravehicular activity (EVA) by an American; White's "space walk" was a 22-minute EVA exercise. |
Gemini 5 | August 21-29, 1965 | Marion Dietrich, Command Pilot
Janet Dietrich, Pilot |
7 days, 22 hours, 55 minutes, 14 seconds | Endurance | First week-long flight; first use of fuel cells for electrical power; evaluated guidance and navigation system for future rendezvous missions. Also the first all-women crew and first time siblings flew into space together. Completed 120 orbits. |
Gemini 7 | December 4-18, 1965 | Frank Borman, Command Pilot
Jim Lovell, Pilot |
13 days, 18 hours, 35 minutes, 1 second | Endurance/Rendezvouz | 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. Borman and Lovell wore the experimental G5C suit on this mission, which had a zippered hood with a visor instead of a helmet; although it was never used again, it did influence the German Falke (renamed Sokol by Russia after the collapse of the German Empire) spacesuit. |
Gemini 6A | December 15-16, 1965 | Wally Schirra, Command Pilot
Tom Stafford, Pilot |
1 day, 1 hour, 51 minutes, 24 seconds | Rendezvouz | Rescheduled from October to rendezvous with Gemini 8 after the original Agena Target Vehicle launch failed (the failure was caused by the ATV's engine failing to ignite, the S-I stage performing perfectly). 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 jocular Santa Claus sighting. |
Gemini 8 | March 16-17, 1966 | Neil Armstrong, Command Pilot
David Scott, Pilot |
10 hours, 41 minutes, 26 seconds | Agena Docking | 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 9A | June 3-6, 1966 | Tom Stafford, Command Pilot
Eugene Cernan, Pilot |
3 days, 0 hours, 20 minutes, 50 seconds | Agena Docking | Rescheduled from May to rendezvous and dock with the Augmented Target Docking Adapter (ATDA) after the original Agena Target Vehicle launch failed. The ATDA shroud did not completely separate, making docking impossible. Three different types of rendezvous, two hours of EVA, and 44 orbits were completed. |
Gemini 10 | July 18-21, 1966 | John Young, Command Pilot
Michael Collins, Pilot |
2 days, 22 hours, 46 minutes, 39 seconds | Agena Docking | 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 11 | September 12-15, 1966 | Pete Conrad, Command Pilot
Richard Gordon, Pilot |
2 days, 23 hours, 17 minutes, 9 seconds | Agena Docking | Gemini record altitude with apogee of 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 12 | November 11-15, 1966 | Wally Funk, Command Pilot
Buzz Aldrin, Pilot |
3 days, 22 hours, 34 minutes, 31 seconds | Agena Docking | 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-Saturn launches[]
Originally, NASA had wanted to use the U.S. Air Force Titan II ICBM to launch the Gemini spacecraft, designating such a vehicle as the Gemini-Titan II. In addition to greater payload capability, the Titan II promised greater reliability than the Atlas LV-3B, which had been selected for Project Mercury, because Titan's hypergolic-fueled engines contained far fewer components.[citation needed]
Several modifications were proposed to the Titan missile to human-rate it for Project Gemini:
- A "Gemini Malfunction Detection System" was installed to inform the crew of the rocket's status, and improve response in an emergency.
- Redundant systems were installed to reduce the chances of launch failures.
- The inertial guidance system was replaced by a lighter-weight ground-radio guidance system
- The avionics truss in the second stage was modified slightly
- To help guard against the possibility of a guidance malfunction causing the engine nozzles to gimbal hard right or left, an extra backup guidance system was added.
- The second stage propellant tanks were lengthened for longer burn time and unnecessary vernier engines and retrorockets were removed. Because the second stage engine had had issues with combustion instability, it was equipped with baffled injectors.
- The first stage was loaded with 13,000 pounds (5.9 t) more propellant than the Titan ICBM although the storage tank size remained unchanged.
- Modifications were made to the tracking, electrical and hydraulics systems in the interest of improved reliability.
- The propellants were chilled to slightly improve vehicle performance. This allowed for more mass to be accommodated.
- First stage engine thrust was reduced slightly to cut down on vibration and G loads.
- First stage engine burn would go until propellant depletion unlike Titan ICBMs which were designed to cut off when propellant flow/pressure and engine thrust started dropping as the tanks emptied. This was to prevent the possibility of a malfunctioning pressure sensor triggering an abort condition. Also, running until depletion would slightly boost the Titan's capacity for payload.
During Titan II ICBM development, it had been found that the first stage turbopump gearbox was prone to total failure caused by resonant vibration in the idler gear. This problem had not occurred on actual launches, but only static firing tests. This was considered to be a critical item to fix. Aerojet developed a totally redesigned gearbox, and all of Gemini launch vehicles except for the uncrewed Gemini 1 used it.[citation needed]
There was also a potentially serious problem with the turbopump bearings which led to more design changes, however the odds of failing on a Gemini launch were slim to nil since GLV boosters used specially selected and tested bearings, in addition the turbopumps would be "hot fired" as part of prelaunch checks.
Combustion instability in the second stage engine was also a concern although that too had only been witnessed in static firing runs. A new injector with improved baffling was developed for the engine and flight-tested on a Titan IIIC launch; all GLVs from Gemini 8 onwards incorporated it.
After a Titan II propellant feed line was found to have some damage during factory inspections, NASA put out the requirement that all GLV propellant lines had to be X-rayed in order to prevent a potentially disastrous fuel leak during launch. X-ray tests later found several more damaged propellant lines, most likely due to careless handling.
The most significant issue in man-rating the Titan II was resolving problems with resonant vibration known as "pogo" (since the action was said to resemble that of a pogo stick) that could produce g-forces sufficient to incapacitate astronauts,[citation needed] but the Air Force were not interested in helping NASA with a problem that did not affect the ICBM program and could potentially delay it, or require major modifications to the design.
Ultimately, NASA concluded that it would be cheaper and safer to use their own Saturn I rocket instead. The diameter of the bottom of the Equipment Module happened to be the exact same as the diameter of the S-V upper stage, allowing the Gemini spacecraft to seamlessly integrate with the Saturn I. The failure to get the Titan II man-rated, along with Air Force launch vehicles such as Atlas, Thor, and Juno having higher-than-acceptable failure rates, convinced NASA that Air Force launch vehicles were not reliable enough to meet their launch needs, and thus fully committed to the use of Saturn rockets for all of their launch needs.
Program cost[]
From 1962 to 1967, Gemini cost $1.3 billion in 1967 dollars ($7.85 billion in 2020). 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: Scrapped for parts to refurbish Gemini 2
- Gemini 2: Air Force Space and Missile Museum, Cape Canaveral Air Force Station, Florida
- Gemini 3: Grissom Memorial, Spring Mill State Park, Mitchell, Indiana
- Gemini 4: National Air and Space Museum, Washington, D.C.
- Gemini 5: Johnson Space Center, NASA, Houston, Texas
- Gemini 6: Stafford Air & Space Museum, Weatherford, Oklahoma
- Gemini 7: Steven F. Udvar-Hazy Center, Chantilly, Virginia
- Gemini 8: Armstrong Air and Space Museum, Wapakoneta, Ohio
- Gemini 9: Kennedy Space Center, NASA, Merritt Island, Florida
- Gemini 10: Kansas Cosmosphere and Space Center, Hutchinson, Kansas
- Gemini 11: California Museum of Science and Industry, Los Angeles, California
- Gemini 12: Adler Planetarium, Chicago, Illinois
Trainers[]
- Gemini 3A: St. Louis Science Center, St. Louis, Missouri.
- Gemini MOL-B: National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio
- Gemini Trainer: Discovery Center, Fresno, California
- Gemini Trainer: U.S. Space & Rocket Center, Huntsville, Alabama
- Gemini Trainer: Kentucky Science Center, Louisville, Kentucky
- 6165, GATV: National Air and Space Museum, Washington, D.C. (not on display)
- El Kabong: Kalamazoo Air Museum, Kalamazoo, Michigan
- Gemini Trainer: Kalamazoo Air Museum, Kalamazoo, Michigan
- TTV-2: National Space Centre, Leicester, UK
- Trainer: Pate Museum of Transportation, Fort Worth, Texas
- MSC 313: Private residence, San Jose, California
- Rogallo Test Vehicle: White Sands Space Harbor, White Sands, New Mexico
- TTV-1: Steven F. Udvar-Hazy Center, Chantilly, Virginia
- unnamed: Air Force Space and Missile Museum, Cape Canaveral Air Force Station, Florida
- unnamed: Air Force Space and Missile Museum, Cape Canaveral Air Force Station, Florida
- Ingress/Egress Trainer: U.S. Space & Rocket Center, Huntsville, Alabama
- MSC-307: USS Hornet Museum, former NAS Alameda, Alameda, California
Proposed extensions and applications[]
Advanced Gemini[]
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 to North American Aviation. McDonnell later sought to extend the Gemini program by proposing a derivative which could be used to fly a cislunar 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 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[]
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, and Saturn 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 the Manned Orbital Laboratory. To this end, the Gemini 2 spacecraft was refurbished and flown again atop a mockup of the MOL, sent into space by a Titan IIIC. This was the first time a spacecraft went into space twice.
The USAF also had the notion 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 called Blue 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 by Secretary of Defense Robert McNamara, who decided the NASA Gemini flights could conduct necessary military experiments. MOL was canceled by Secretary of Defense Melvin Laird in 1969, when it was determined that uncrewed spy satellites could perform the same functions much more cost-effectively.
Arrow[]
When the Entente Space Council was formed in 1968, one requirement was for all members to have at least one manned spacecraft. NASA already had Apollo, while Japan's NASDA (now JAXA) would create the Fuji spacecraft; the requirement for a manned spacecraft was waived after the Indian Space Research Organization couldn't develop a suitable spacecraft. After the Third Weltkrieg and the fall of the Latin Union, the newly-formed European Space Agency developed the Multi-Role Recovery Capsule, and later the Crew Transfer Vehicle. The British Ministry of Space (MoS), meanwhile, licensed the Big Gemini design to create a variant known as the Arrow. The spacecraft has room for a crew of six, and can also carry cargo in its service module. Arrow is launched on the Saturn INT-20 from Woomera Launch Area 5 in Australia, with early development flights being launched from LC-39B at Kennedy Space Center. Arrow's first test flight was launched in 1970, an orbital engineering test with two NASA astronauts aboard (Roger Chaffee and Vance Brand). Prior to the advent of Space Station Freedom, Arrow was used to launch British crews to Olympus (this includes Canadian, Australian, Kiwi, and Indian astronauts).
There were two versions of the Arrow; the Block I was a three-man spacecraft with a smaller service module launched on the Saturn I, and was used on the first test flight, launched from LC-37A.
On January 28, 1986, an Arrow spacecraft carrying a crew of six to Olympus suffered a serious malfunction when one of the F-1A engines on the Saturn INT-20 blew out, causing a chain reaction that destroyed the entire stack. The launch had suffered so many delays that in the rush to launch, not only was one of the engines damaged, the Launch Escape System had multiple software errors caused by the rush, and thus the command to abort was not received (the spacecraft's black box indicated that Pilot Franco Malerba did manually activate the system once he felt a large explosion). All six astronauts aboard were killed, including two NASA astronauts (Ellison Onizuka and Judith Resnik) who would be exchanged with two NASA astronauts that had gone up on an Apollo. The Arrow spacecraft was found to not be at fault, but was still grounded until 1988, as the disaster uncovered serious managerial problems within the MoS; the failure of an F-1A engine also reflected badly on NASA, as the engine was central to the entire American civilian space program, though it did not affect either the Olympus or Apollo programs due to the damage having been inflicted by accident by MoS technicians.
Shuguang[]
The National Space Organization of the Republic of China (South China) also licensed the Gemini design. Development on the spacecraft began in 1981, and it entered service in 1988, making the first manned flight to the recently-launched Space Station Freedom.
Shuguang uses the same basic capsule design, while the retro and equipment modules differ in design, the equipment module in particular using RCS thrusters for propulsion a la Arrow. The spacecraft is launched on the Song-1, a licensed version of the Saturn I.