Gemini program

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Gemini logo
Titan II rocket at Gemini 9 launch
Astronaut groups 1 (seated) and 2 (standing)
Astronaut group 3
Gemini spaceship
Agena target satellite

The Gemini program was the second manned space program in the United States after the Mercury program . The aim of the Gemini program was to develop procedures and technologies for the Apollo program . In its framework, ten manned space flights took place in 1965 and 1966, during which astronauts performed, among other things, the first coupling maneuvers in space and the first American space exits.

The planning

Gemini was born out of necessity, and NASA was able to make a virtue out of it. After the Mercury flights were discontinued, it became clear relatively early on that there would be a gap of three or even four years until the start of the Apollo missions - valuable years that were urgently needed to develop the necessary technologies, e.g. B. coupling mechanisms, life support systems, EVA suits, etc. to test. The program was approved on December 7, 1961. Originally, consideration was given to expanding the existing Mercury system into a two-man spaceship called the Mercury Mark II. The advantage would have been to save development costs by using existing technology and to be able to bridge the time until the start of the manned Apollo flight program. The main changes were the installation of a second seat, the installation of a powerful maneuvering unit and the use of an already existing upper stage as a docking dummy. To simplify handling, a modular interior was also planned, which would have made it easier to replace or add components and would have made the Mercury Mark II a powerful platform for manned space flights.

The realized spaceship differed from Mercury, among other things, in that all elements that were not required upon re-entry were outsourced to a supply module that could be separated in two phases. Before re-entry, the equipment was first disconnected. A frustoconical braking unit then remained on the re-entry part , which was also separated after braking. The braking unit would also have been used in the event of an emergency during ascent to separate the capsule from the missile.

Gemini stands in Latin for the constellation Gemini , with which the name refers to the two-seater spaceship and the rendezvous maneuvers. In addition, the mythological twins Castor and Pollux are the gods of travelers. The program was officially named on January 3, 1962, after a request for proposals in December 1961. The name Gemini was suggested by two people.

The astronauts

To support the already trained Mercury astronauts, NASA decided on April 18, 1962 to recruit five to ten new astronauts, to which 253 applications were received.

On September 17, 1962, Group 2, consisting of nine astronauts, was presented to the public. These were Neil Armstrong , Frank Borman , Charles Conrad , James Lovell , James McDivitt , Elliot See , Thomas Stafford , Edward White, and John Young .

The selection of the third group of astronauts began on June 5, 1963 with another tender. NASA presented the 14 successful applicants on October 18, 1963: Edwin Aldrin , William Anders , Charles Bassett , Alan Bean , Eugene Cernan , Roger Chaffee , Michael Collins , Walter Cunningham , Donn Eisele , Theodore Freeman , Richard Gordon , Russell L. Schweickart , David Scott and Clifton Williams .

This increased the number of active astronauts for the Gemini and Apollo programs to 27, as the Mercury astronauts Glenn , Carpenter and Slayton were not available for the Gemini program for various reasons.

Theodore Freeman died on October 31, 1964 in an airplane accident. Elliot See and Charles Bassett, who were scheduled to be crew members for Gemini 9, were also killed in a plane crash on February 28, 1966. Virgil Grissom , Edward White and Roger Chaffee died in the Apollo 1 catastrophe on January 27, 1967 , and Clifton Williams had an airplane accident on October 5, 1967.

Manned missions

mission begin landing Duration crew aims comment
Gemini 3
Gemini 3
March 23, 1965 March 23, 1965 00d 04h 52min Virgil Grissom ,
John Young
first two-man flight by the Americans
Gemini 4
Gemini 4
0Jun 3, 1965 0Jun 7, 1965 04d 01h 56min James McDivitt ,
Edward H. White
First space exit of the Americans by Edward White
Gemini 5
Gemini 5
Aug 21, 1965 Aug 29, 1965 07d 22h 55min Gordon Cooper ,
Charles Conrad
Launching and rendezvous maneuvers with a target satellite carried 120 completed circumnavigations of the earth
Gemini 6
Gemini 6
Dec 15, 1965 Dec 16, 1965 01d 01h 51min Walter Schirra ,
Tom Stafford
Rendezvous with Gemini 7 The rendezvous planned for October 1965 with the unmanned Agena satellite had to be omitted because the launch vehicle exploded after takeoff. Gemini 6 launch has been postponed to December after Gemini 7 launch. This flight also runs under the number 6-A.
Gemini 7
Gemini 7
0Dec. 4, 1965 Dec 18, 1965 13d 18h ​​35min Frank Borman ,
James A. Lovell
two-week flight, rendezvous with Gemini 6, which started eleven days after Gemini 7 Mission objective: Evidence for the realization of a 14-day space flight
Gemini 8
Gemini 8
March 16, 1966 March 17, 1966 00d 10h 41min Neil Armstrong ,
David Scott
Coupling with GATV target satellite Problems with the controls, spaceship rotates while coupling with Agena, flight aborted
Gemini 9
Gemini 9
0Jun 3, 1966 0Jun 6, 1966 03d 00h 21min Tom Stafford ,
Eugene Cernan
Rendezvous with ATDA target satellite The planned coupling failed because the panel on the target satellite had not come off
Gemini 10
Gemini 10
Jul 18, 1966 Jul 21, 1966 02d 22h 47min John Young ,
Michael Collins
Coupling with GATV target satellites first coupling with target satellite and use of the propulsion of the alien spacecraft; new altitude record (763 km)
Gemini 11
Gemini 11
Sep 12 1966 Sep 15 1966 02d 23h 17min Charles Conrad ,
Richard Gordon
Coupling with GATV target satellite new altitude record (1374 km)
Gemini 12
Gemini 12
Nov 11, 1966 Nov 15, 1966 03d 22h 35min James A. Lovell ,
Edwin "Buzz" Aldrin
Coupling with GATV target satellite Until then, longest space exit with 5½ hours

With the landing of Gemini 12 on November 15, 1966 and the official closure of the Gemini office on February 1, 1967, the Gemini program ended.

Technical specifications

Gemini spaceship preparing for launch

Gemini spaceship

The space capsule of the Gemini spaceship was 5.8 meters long and three meters in diameter. The hatches could be opened and closed while in space, allowing activities outside of the spaceship. A special coupling module was provided for the docking maneuvers . The mass of the space capsule was approx. 3,800 kg. For the first time a polymer electrolyte fuel cell was used as the primary energy supply in a spaceship . Non-rechargeable batteries were only intended for re-entry and emergencies. For the first time, an on-board computer, the Gemini Digital Computer , was used to support the crew with calculations. The computer, made up of 5 boards with 510 modules, had a memory of only 4096 instruction words of 39 bits each. Since this turned out to be too small, from Gemini 8 onwards it was supplemented by a magnetic tape drive, which increased the storage capacity seven times.

Missile serial numbers

Gemini 6 during the rendezvous with Gemini 7

Like the Mercury Redstone and Mercury Atlas rockets before them, the Gemini-Titan rockets were ordered by NASA through the United States Air Force and were actually rockets intended for military use. The Air Force was responsible for launch complex 19 at Cape Canaveral Air Force Station and prepared and executed all Gemini launches. Therefore, the first and second stages also had serial numbers of the US Air Force. They were placed on opposite sides at the bottom of the step. Since the rockets had been ordered in 1962, a serial number should actually follow the template 62-12XXX . However, only 12XXX was noted on the steps of the Titan II .

  • 12556 - GLV-1 - Gemini 1
  • 12557 - GLV-2 - Gemini 2
  • 12558 - GLV-3 - Gemini 3
  • 12559 - GLV-4 - Gemini 4
  • 12560 - GLV-5 - Gemini 5
  • 12561 - GLV-6 - Gemini 6-A
  • 12562 - GLV-7 - Gemini 7
  • 12563 - GLV-8 - Gemini 8
  • 12564 - GLV-9 - Gemini 9A
  • 12565 - GLV-10 - Gemini 10
  • 12566 - GLV-11 - Gemini 11
  • 12567 - GLV-12 - Gemini 12
  • 12568 - GLV-13 Ordered by NASA 1962, canceled July 30, 1964 / not built
  • 12569 - GLV-14 Ordered by NASA 1962, canceled July 30, 1964 / not built
  • 12570 - GLV-15 Ordered by NASA in 1962, canceled on July 30, 1964 / not built

Gemini Space Suit and Astronaut Maneuvering Unit (AMU)

see Gemini Space Suit and Astronaut Maneuvering Unit


After the Project Mercury, which is the theoretical possibility of manned space flights also demonstrated after the first successes of the Soviet Union, were achieved with Gemini significant progress in the process of testing the necessary for a successful lunar flight maneuvers in space: rendezvous and coupling of spacecraft, spacewalks , Orbit changes and the cooperation of the ground station with the pilots.

Gemini was thus an extremely successful program, which also proved that it was possible to master severe accidents as in the case of Gemini 8 . A cornerstone was laid for the Apollo moon missions. However, in 1967, at the beginning of the Apollo program, a severe setback occurred with the loss of three lives on the ground at Apollo 1 . The Soviet space program also experienced a setback that year when the commander of Soyuz 1 had an accident on landing.

The experiences from the Gemini program contributed significantly to the first successful manned moon landing of Apollo 11 .

See also

Individual evidence

  1. Bernd Leitenberger: The technology of the Gemini program Extract from The Gemini program: Technology and history
  2. Helen T. Wells, Susan H. Whiteley, Carrie E. Karegeannes: Gemini. In: Origins of NASA Names. NASA History Office, 1976, p. 104 , accessed October 17, 2010 .
  3. Bernd Leitenberger: The Gemini program p. 22
  4. ^ Metzler, Rudolf: Hallo Erde , Loewes Verlag Ferdinand Carl KG, Bayreuth 1969


German-language literature is marked accordingly

NASA Mission Reports

  • Robert Godwin: Gemini 12: The NASA Mission Reports ; Apogee Books, 2004; ISBN 1-894959-04-3 (book & CD)
  • Robert Godwin: Gemini 7: The NASA Mission Reports ; Collector's Guide Publishing, 2002; ISBN 1-896522-82-3 (book & CD)
  • Robert Godwin: Gemini 6: The NASA Mission Reports ; Apogee Books, 2000; ISBN 1-896522-61-0 (book & CD)


  • Carl R. Green: The Gemini 4 Spacewalk Mission ;, 2004; ISBN 0-7660-5163-3
  • David M. Harland: How NASA Learned to Fly in Space: An Exciting Account of the Gemini Missions ; Apogee Books, 2004; ISBN 1-894959-07-8
  • Helen Zelon: The First American Space Walk: The Gemini IV Mission ; PowerKids Press, 2002; ISBN 0-8239-5771-3
  • David J. Shayler: Gemini ; Springer-Verlag Telos, 2001; ISBN 1-85233-405-3
  • Diane M. and Paul P. Sipiera: Project Gemini ; Children's Press, 1997; ISBN 0-516-20441-6
  • Diverse: People to the Moon - Gemini 4 and Gemini 6/7 ; Inter-Pathé-Film Ing. Paul Schmitt GmbH + Co KG; ISBN 3-89396-119-4 (German)
  • Bernd Leitenberger: The Gemini Program: Technology and History ; 3rd, expanded edition. Books on Demand, Norderstedt 2010, ISBN 978-3-83914-7-986 . (German)


  • The NASA Program - The Gemini Program (German)

Web links

Commons : Gemini program  - collection of pictures, videos and audio files