Project Gemini

McDonnell Gemini spacecraft
Gemini spacecraft in orbit.
Diameter:	10 ft	3.05 m
Volume:	90 ft³	2.55 m³
Weights
Reentry module:	4,372 lb	1,983 kg
Retrograde module:	1,303 lb	591 kg
Equipment module:	2,815 lb	1,277 kg
Total:	8,490 lb	3,851 kg
Rocket engines
Retros (solid fuel) x 4:	2,500 lbf ea	11.12 kN
Reentry Control System (N₂O₄/MMHH) x 16:	25 lbf ea	111 N
OAMS (N₂O₄/MMHH) x 2:	85 lbf ea	378 N
OAMS (N₂O₄/MMHH) x 6:	100 lbf ea	445 N
OAMS (N₂O₄/MMHH) x 8:	25 lbf ea	111 N
Performance
Endurance:	14 days	206 orbits
Apogee:	250 miles	402 km
Perigee:	100 miles	160 km
Spacecraft delta v:	728 ft/s	222 m/s
Gemini spacecraft diagram
Gemini spacecraft diagram (NASA)
McDonnell Gemini Spacecraft

Project Gemini was the second human spaceflight program of the National Aeronautics and Space Administration. It operated between Projects Mercury and Apollo, with 10 manned flights occurring in 1965 and 1966. Its objective was to develop techniques for advanced space travel, notably those necessary for Project Apollo, whose objective was to land men on the Moon. Gemini missions included the first American extravehicular activity, and new orbital maneuvers including rendezvous and docking.

Gemini was originally seen as a simple extrapolation of the Mercury program, and thus early on was called Mercury Mark II. The actual program had little in common with Mercury and was in fact superior to even Apollo in some ways. (See Big Gemini.) This was mainly a result of its late start date, which allowed it to benefit from much that had been learned during the early stages of the Apollo project (which, despite its later launch dates, was actually begun before Gemini).

Its primary difference from Mercury was that the earlier spacecraft had all systems other than the reentry rockets situated within the capsule, to which access of nearly all was through the astronaut's hatchway, while Gemini had many power, propulsion, and life support systems in a detachable module like a huge bowl; many components in the capsule itself were reachable each through its own small access door. The original intention was for Gemini to land on solid ground instead of at sea, using a paraglider rather than a parachute, and for the crew to be seated upright controlling the forward motion of the craft before its landing. To facilitate this, the parachute cord did not attach just to the nose of the craft; there was an additional attachment point for balance near the heat shield. This cord was covered by a strip of metal between the doors. Early short-duration missions had their electrical power supplied by batteries; later endurance missions had the first fuel cells in manned spacecraft.

The "Gemini" designation comes from the fact that each spacecraft held two men, as "gemini" in Latin means "twins". Gemini is also the name of the third constellation of the Zodiac and its twin stars, Castor and Pollux.

Unlike Mercury, which could only change its orientation in space, the Gemini capsule could alter its orbit. It could also dock with the Agena Target Vehicle, which had its own large rocket engine and was used to perform large orbital changes. Gemini was the first American manned spacecraft to include an onboard computer, the Gemini Guidance Computer, to facilitate management and control of mission maneuvers. It was also unlike other NASA craft in that it used ejection seats, in-flight radar and an artificial horizon - devices borrowed from the aviation industry. Using ejection seats to push astronauts to safety was first employed by the Soviet Union in the Vostok craft manned by cosmonaut Yuri Gagarin.

Gemini was designed by a Canadian, Jim Chamberlin, formerly the chief aerodynamicist on the Avro Arrow fighter interceptor program with Avro Canada. Chamberlin joined NASA along with 25 senior Avro engineers after cancellation of the Arrow program, and became head of the U.S. Space Task Group’s engineering division in charge of Gemini. The main contractor was McDonnell, which had lost out on main contracts for the Apollo Project. McDonnell sought to extend the program by proposing a Gemini craft which could be used to fly a cislunar mission and even achieve a manned lunar landing earlier and at less cost than Apollo, but these proposals were rejected.

The Gemini program cost $5.4 billion. See NASA Budget.

Team

The Gemini program was managed by the Manned Spacecraft Center, Houston, Texas, under direction of the Office of Manned Space Flight, NASA Headquarters, Washington, D.C, Dr. George E. Mueller, Associate Administrator of NASA for Manned Space Flight, served as acting director of the Gemini program. William C. Schneider, Deputy Director of Manned Space Flight for Mission Operations, served as Mission Director on all Gemini flights beginning with Gemini VI.

Program objectives

The Gemini Program was conceived after it became evident to NASA officials that an intermediate step was required between the projects Mercury and Apollo. The major objectives assigned to Gemini were:

To subject two men and supporting equipment to long-duration flights, a requirement for projected later trips to the Moon or deeper space.
To effect rendezvous and docking with other orbiting vehicles, and to maneuver the docked vehicles in space, using the propulsion system of the target vehicle for such maneuvers.
To perfect methods of reentry and landing the spacecraft at a pre-selected land-landing point.
To gain additional information concerning the effects of weightlessness on crew members and to record the physiological reactions of crew members during long-duration flights.
To accomplish EVA, (Extra Vehicular Activity) or space-walks outside the protection of the space craft.

After 10 successful flights, the Gemini program clearly placed the United States in the lead over the Soviet Union in manned spaceflight. The flight of Gemini VIII concluded with the successful emergency recovery of the tumbling orbiting capsule piloted by Neil Armstrong and David Scott.

Gemini applications

Military

Replica of a Gemini capsule at the Neil Armstrong Air and Space Museum

A cutaway of the Project Gemini spacecraft

The United States Air Force had an interest in the system, and decided to use its own modification of the spacecraft as the crew vehicle for the Manned Orbital Laboratory. To this end, one of the unmanned Gemini spacecraft was refurbished and flown again atop a mockup of the MOL, sent into space by a Titan III-M. This was the first time a spacecraft went into space twice.

The USAF also had the notion of adapting the Gemini spacecraft for 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 US Air Force did not like the fact that Gemini would have to be recovered by the US Navy, so they intended for Blue Gemini eventually to use the paraglider and land on three skids, something from the original design of Gemini.

At first some within NASA welcomed sharing of the cost with the USAF, but it was later agreed that NASA was better off operating Project Gemini by itself. MOL was cancelled in 1968 and Blue Gemini too was cancelled without any use by military astronauts.

Other proposals

Other Gemini derivatives were proposed, including Gemini LOR, Gemini Lunar Lander, Gemini-Centaur, Gemini Ferry, Gemini Transport, Gemini - Saturn I, Gemini - Saturn IB, Gemini - Saturn V, Gemini Pecan, Extended Mission Gemini, Gemini - Double Transtage, Gemini Satellite Inspector, Gemini Lunar Surface Rescue Spacecraft, Gemini observatory, Gemini Paraglider, Rescue Gemini, Winged Gemini, Gemini LORV and Gemini Lunar Surface Survival Shelter.^[1]

Current

In 2005, NASA Administrator Michael Griffin announced that the new Orion spacecraft, an Apollo-derived spacecraft, would use the Gemini/Agena chasedown and docking technique when NASA starts sending crews back out to the Moon by 2020. The Orion, which will replace the Space Shuttle (which currently lands on a conventional runway similar to the early Gemini and Blue Gemini paraglider/skids technique), was originally designed to land on solid ground using deployable airbags or a Soyuz-style retrorocket system, but it is currently envisioned to be recovered in the ocean.

In addition, NASA may opt to replace the proposed launch escape system with the so-called Max Launch Abort System (MLAS) which would work in the same fashion as the Mercury and Apollo escape towers, but incorporate the rockets into the launch shroud itself, eliminating the tower altogether and allowing the Orion spacecraft to resemble the towerless Gemini-Titan launch system.

Liftoff of Gemini 6A from Pad 19 with astronauts Walter Schirra and Thomas Stafford aboard

Astronauts

The following astronauts flew on the 10 Gemini missions:

From Astronaut Group 1
Astronaut	Service	Mission
Leroy Gordon Cooper, Jr.	USAF	Gemini V
Virgil Ivan "Gus" Grissom	USAF	Gemini III
Walter Marty Schirra, Jr.	USN	Gemini VI-A
From Astronaut Group 2
Astronaut	Service	Mission
Neil Alden Armstrong	(ret. USN)	Gemini VIII
Frank Frederick Borman II	USAF	Gemini VII
Charles "Pete" Conrad, Jr.	USN	Gemini V, Gemini XI
James Arthur Lovell, Jr.	USN	Gemini VII, Gemini XII
James Alton McDivitt	USAF	Gemini IV
Thomas Patten Stafford	USAF	Gemini VI-A, Gemini IX-A
Edward Higgins White II	USAF	Gemini IV
John Watts Young	USN	Gemini III, Gemini X
From Astronaut Group 3
Astronaut	Service	Mission
Edwin Eugene "Buzz" Aldrin	USAF	Gemini XII
Eugene Andrew Cernan	USN	Gemini IX-A
Michael Collins	USAF	Gemini X
Richard Francis Gordon, Jr.	USN	Gemini XI
David Randolph Scott	USAF	Gemini VIII

Crew selection

Deke Slayton as head of the Astronaut Office had the main role in the choice of crews for the Gemini program. This selection process, with the prospect of more ambitious missions that would follow with Apollo, became even more political than in the Mercury Program. With Gemini it became a procedure that each flight had a primary crew and backup crew and that the backup crew would rotate to primary crew status three flights later. Slayton also intended for first choice of mission commands to be given to the four remaining active astronauts of the Mercury Seven, Alan Shepard, Gus Grissom, Gordon Cooper and Wally Schirra. John Glenn had retired from NASA in January 1964 and 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. Slayton himself continued to be grounded due to a heart problem.

In late 1963, Slayton selected Alan Shepard and Thomas Stafford for Gemini 3, James McDivitt and Ed White for Gemini 4, and Wally Schirra and John Young for Gemini 5 (the first Agena rendezvous mission). Gemini 3 was backed up by Gus Grissom and Frank Borman, who were also slated for Gemini 6, the first long-duration mission. Finally Pete Conrad and James Lovell were assigned as the backup for Gemini 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 now were the backup crew for Shepard and Stafford. Grissom and Borman now had their long-duration mission assigned to Gemini 5.

The second rearrangement occurred when Alan Shepard developed Meniere's disease, an inner ear problem. Gus Grissom was moved to command Gemini 3. Slayton felt that Young was a better personality match with Grissom and switched Stafford and Young. Finally Slayton tapped Gordon Cooper to command the long-duration Gemini 5. Again for reasons of compatibility he moved Pete Conrad from being the backup commander of Gemini 4 to be the pilot of Gemini 5, and Frank Borman to the backup command of Gemini 4. Finally he assigned Neil Armstrong and Elliot See to be the backup crew for Gemini 5.

The third rearrangement of crew assignment occurred when Deke Slayton felt that Elliot See wasn't up to the physical demands of EVA on Gemini 8. He reassigned Elliot See to be the prime commander of Gemini 9 and put Dave 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 Elliot See and Charles Bassett in a plane crash in St. Louis. The backup crew of Tom Stafford and Eugene Cernan was moved up to become the new prime crew of Gemini 9. James Lovell and Edwin "Buzz" 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, and Chaffee in the fire of Apollo 1, this rearrangement is what finally determined the makeup of the early Apollo crews. These events were decisive in determining who would be in position to first walk on the Moon.

In his autobiography Deke! Slayton relates that he would probably have replaced Aldrin with Eugene Cernan, the backup pilot for Gemini 12, if the second flight of the AMU had flown on Gemini 12.

Missions

There were 12 Gemini flights, including two unmanned flight tests. All were launched by Titan II rockets.

Unmanned

Mission	LV Serial N^o	Mission Dates	Launch Time	Duration	Remarks
Gemini 1	GLV-1 12556	8 April-12, 1964	16:01 UTC	03d 23h	First test flight of Gemini
Gemini 2	GLV-2 12557	19 January 1965	14:03 UTC	00d 00h 18m 16s	Suborbital flight to test heat shield

Manned

Mission	LV Serial N^o	Command Pilot	Pilot	Mission Dates	Launch Time	Duration
Gemini III	GLV-3 12558	Grissom	Young	23 March 1965	14:24 UTC	00d 04h 52m 31s
Gemini III	First manned Gemini flight, three orbits.
Gemini IV	GLV-4 12559	McDivitt	White	3 June-07, 1965	15:15 UTC	04d 01h 56m 12s
Gemini IV	Included first extravehicular activity (EVA) by an American; White's "space walk" was a 22 minute EVA exercise.
Gemini V	GLV-5 12560	Cooper	Conrad	21 August-29, 1965	13:59 UTC	07d 22h 55m 14s
Gemini V	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	Borman	Lovell	4 December-18, 1965	19:30 UTC	13d 18h 35m 01s
Gemini VII	When the original Gemini VI mission was scrubbed because its Agena target for rendezvous and docking failed, Gemini VII was used for the rendezvous instead. Primary objective was to determine whether humans could live in space for 14 days.
Gemini VI-A	GLV-6 12561	Schirra	Stafford	December 15-16, 1965	13:37 UTC	01d 01h 51m 24s
Gemini VI-A	First space rendezvous accomplished with Gemini VII, station-keeping for over five hours at distances from 0.3 to 90 m (1 to 300 ft).
Gemini VIII	GLV-8 12563	Armstrong	Scott	16 March-17, 1966	16:41 UTC	00d 10h 41m 26s
Gemini VIII	Accomplished first docking with another space vehicle, an unmanned Agena stage. When undocked, a Gemini spacecraft thruster malfunction caused near-fatal tumbling of the craft, which Armstrong was able to overcome; the crew effected the first emergency landing of a manned U.S. space mission.
Gemini IX-A	GLV-9 12564	Stafford	Cernan	3 June-6, 1966	13:39 UTC	03d 00h 21m 50s
Gemini IX-A	Rescheduled from May to rendezvous and dock with augmented target docking adapter (ATDA) after original Agena target vehicle failed to orbit. ATDA shroud did not completely separate, making docking impossible. Three different types of rendezvous, two hours of EVA, and 44 orbits were completed.
Gemini X	GLV-10 12565	Young	Collins	18 July-21, 1966	22:20 UTC	02d 22h 46m 39s
Gemini X	First use of Agena target vehicle's propulsion systems. Spacecraft also rendezvoused with Gemini VIII target vehicle. Collins had 49 minutes of EVA standing in the hatch and 39 minutes of EVA to retrieve experiment from Agena stage. 43 orbits completed.
Gemini XI	GLV-11 12566	Conrad	Gordon	12 September-15, 1966	14:42 UTC	02d 23h 17m 08s
Gemini XI	Gemini record altitude, 1,189.3 km (739.2 mi) reached using Agena propulsion system after first orbit rendezvous and docking. Gordon made 33-minute EVA and two-hour standup EVA. 44 orbits.
Gemini XII	GLV-12 12567	Lovell	Aldrin	11 November-15, 1966	20:46 UTC	03d 22h 34m 31s
Gemini XII	Final Gemini flight. Rendezvoused and docked manually with its target Agena and kept station with it during EVA. Aldrin set an EVA record of 5 hours 30 minutes for one space walk and two stand-up exercises, and demonstrated improvements to previous EVA problems.

Gemini-Titan launches and serial numbers

The Gemini-Titan launch vehicles, like the Mercury-Atlas vehicles before them, were ordered by NASA through the U. S. Air Force and were in reality missiles. The Gemini-Titan II rockets were assigned U.S. 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). U.S. Air Force crews maintained Launch Complex 19 and prepared and launched all of the Gemini-Titan II launch vehicles.

Gemini 6A launch. USAF serial number location on Titan II.

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 fifteen launch vehicles was cancelled on 30 July 1964, and they were never built. Serial numbers were, however, assigned to them prospectively: 12568 - GLV-13; 12569 - GLV-14; and 12570 - GLV-15.

All Gemini Launches from GT-1 through GT-12.

Gemini-Titan in fiction

The Doctor Who story The Tenth Planet features a manned space program called Zeus, modeled after Gemini.

In an episode of Chuck Jones' Tom and Jerry, "Puss N Boats", The Gemini spacecraft appeared in the cartoon as a possible debut of the project.

Two Gemini spacecraft (called "Jupiter" in the film) play a role in the James Bond movie You Only Live Twice. The first is captured in space by an unidentified (and supposedly Soviet) spacecraft early in the movie. A second almost meets the same fate during the final showdown, but is saved by Bond who blows up the hostile vessel seconds before it can capture the capsule.

In the 1968 Robert Altman-directed film Countdown, a modified Gemini spacecraft is sent to the moon with a single astronaut in an effort to beat the Soviets following delays to Apollo. In the film the mission and craft are called Pilgrim. The film uses footage from both Gemini and Apollo launches. In real life, contractors for Project Gemini made proposals to NASA to develop the Gemini spacecraft as a cheaper and quicker vehicle to carry out a cislunar mission.

In the 1964 novel Marooned, by Martin Caidin, a Mercury astronaut is stranded in Earth's orbit and a boilerplate Gemini (GT-2) is launched to rescue.

The novel Autopsy for a Cosmonaut, by Jacob Hay and John Keshishian, is an account of a pathologist trained for a Gemini 12-A flight and EVA, to conduct in-flight autopsies of Soviet cosmonauts who have perished in a marooned Voskhod prototype.

In the comic book series Dan Cooper number 16 - "SOS dans l'espace" by Albert Weinberg, a "Gemini 13" mission plays an important role.

In the TV series I Dream of Jeannie, footage from the project is used to depict a fictional Gemini mission.

Current location of hardware

Spacecraft

Gemini 1 - Destroyed

Gemini 2 - U.S. Air Force Space Museum, Cape Canaveral Air Station, FL

Gemini 3 (Molly Brown) - 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 - Oklahoma History Center, Oklahoma City, OK

Gemini VII - Stephen F. Udvar-Hazy Center, Chantilly, VA

Gemini VIII - Armstrong Air and Space Museum, Wapakoneta, Ohio

Gemini IX - Kennedy Space Center, NASA, Cape Canaveral, Florida

Gemini X - Kansas Cosmosphere and Space Center, Hutchinson, KS

Gemini XI - California Museum of Science and Industry

Gemini XII - Adler Planetarium, Chicago, IL

Trainers

Gemini 3A - St. Louis Science Center, St. Louis, MO

Gemini MOL-B - US Air Force Museum , Wright-Patterson Air Force Base, Dayton, OH

Gemini Trainer - US Space & Rocket Center, Huntsville, AL

Gemini Trainer Goddard Space Flight Center, NASA, Greenbelt, MD

Gemini Trainer Louisville Science Center, Louisville, KY

6165 National Air and Space Museum, Washington D.C. Not on Display

El Kabong - Kalamazoo Air Museum, Kalamazoo, MI

Gemini Trainer - Kalamazoo Air Museum, Kalamazoo, MI

TTV-2 National Museum of Scotland, Edinburgh, Scotland

Trainer - Pate Museum of Transportation, Fort Worth, TX

MSC 313 - Private Residence, San Jose, CA

Rogallo Test Vehicle - Space Harbor, White Sands NM

TTV-1 - Stephen F. Udvar-Hazy Center, Chantilly, VA

unnamed - U.S. Air Force Space Museum, Cape Canaveral Air Station, FL

Trainer - U.S. Astronaut Hall of Fame, Titusville, Florida

MSC-307 - USS Hornet Museum, Alameda, CA

References

↑ Astronautix's Gemini

External links

On the Shoulders of Titans: A History of Project Gemini by Barton C. Hacker and James M. Grimwood
John F. Kennedy Space Center - The Gemini Program
NASA Project Gemini site
Space history: Gemini Program space history - Gemini missions spaceflight
Project Gemini Drawings and Technical Diagrams
Technical Diagrams and Drawings
Gemini familiarization Manuals (PDF).
Gemini Designer Jim Chamberlin Bio
Direct Flight Apollo Study: Gemini Spacecraft Applications : document on the proposed Gemini-based Apollo program.
NASA History Series Publications (many of which are on-line)

Archival Materials:

Project Gemini McDonnell Employee Video Interviews and Archival Documents: Western Historical Manuscripts Collection in St. Louis, Missouri