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Gemini 1



Gemini 1 was an uncrewed orbital test of the Titan 2 launch vehicle, the Gemini spacecraft structural integrity, and the launch vehicle-spacecraft compatibility. The test covered all phases through the orbital insertion phase. Other objectives were to check out launch vehicle-spacecraft launch heating conditions, launch vehicle performance, launch vehicle flight control system switch-over circuits, launch vehicle orbit insertion accuracy, and the malfunction detection system. This was the first production Gemini spacecraft and launch vehicle.

Mission Profile

Launch of Gemini 1 took place at 11:00:01 a.m. EST (16:00:01.69 UT) from Complex 19. Six minutes after launch, the Titan 2 booster placed the Gemini spacecraft and the attached 2nd stage in a 160.5 x 320.6 km orbit with a period of 89.3 minutes. An excess speed of 22.5 km/hr sent the spacecraft 33.6 km higher than planned. Mission plans did not include separation of spacecraft from the 3.05 meter diameter, 5.8 meter long Titan stage 2, both orbited as a unit. The planned mission included only three orbits and ended about 4 hours 50 minutes after launch with the third pass over Cape Kennedy. The spacecraft was tracked until it reentered the atmosphere and disintegrated on the 64th orbital pass over the southern Atlantic on April 12. The systems functioned well within planned tolerances and the mission was deemed a successful test.

Spacecraft and Subsystems

The Gemini spacecraft was a cone-shaped capsule consisting of two components, a reentry module and an adaptor module. The adaptor module made up the base of the spacecraft. It was a truncated cone 228.6 cm high, 304.8 cm in diameter at the base and 228.6 cm at the upper end where it attached to the base of the reentry module. The re-entry module consisted of a truncated cone which decreased in diameter from 228.6 cm at the base to 98.2 cm, topped by a short cylinder of the same diameter and then another truncated cone decreasing to a diameter of 74.6 cm at the flat top. The reentry module was 345.0 cm high, giving a total height of 573.6 cm for the Gemini spacecraft.

The adaptor module was an externally skinned, stringer framed structure, with magnesium stringers and an aluminum alloy frame. The adaptor was composed of two parts, an equipment section at the base and a retrorocket section at the top. The reentry module consisted mainly of the pressurized cabin designed to hold the two Gemini astronauts. Two instrumentation pallets were mounted in place of the couches which would normally hold the astronauts. The pallets carried some 180 kg of pressure transducers, temperature sensors, and accelerometers. Separating the reentry module from the retrorocket section of the adaptor at its base was a curved silicone elastomer ablative heat shield. The module was composed predominantly of titanium and nickle-alloy with beryllium shingles. Dummy packages and ballast was used to simulate normal spacecraft weight and configuration for systems not required for this flight.

Gemini Program

The Gemini program was designed as a bridge between the Mercury and Apollo programs, primarily to test equipment and mission procedures in Earth orbit and to train astronauts and ground crews for future Apollo missions. The general objectives of the program included: long duration flights in excess of of the requirements of a lunar landing mission; rendezvous and docking of two vehicles in Earth orbit; the development of operational proficiency of both flight and ground crews; the conduct of experiments in space; extravehicular operations; active control of reentry flight path to achieve a precise landing point; and onboard orbital navigation. Each Gemini mission carried two astronauts into Earth orbit for periods ranging from 5 hours to 14 days. The program consisted of 10 crewed launches, 2 uncrewed launches, and 7 target vehicles, at a total cost of approximately 1,280 million dollars.

Alternate Names

  • 00782
  • GT-1
  • Gemini Titan 1
  • Gemini1

Facts in Brief

Launch Date: 1964-04-08
Launch Vehicle: Titan II
Launch Site: Cape Canaveral, United States
Mass: 5170 kg

Funding Agency

  • NASA-Office of Manned Space Flight (United States)


  • Engineering

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. George E. MuellerProgram ManagerNASA
Dr. William C. SchneiderProject ManagerNASA Headquarters
Dr. Charles W. MathewsProject ManagerNASA Headquarters

Selected References

  • Gilruth, R. R., and G. M. Low, Gemini midprogram conference including experimental results, NASA, SP-121, 1966. (Papers Presented at the Manned Spaceflight Center, Houston, Feb. 23-25, 1966)
  • Gemini summary conference, NASA, SP-138, Wash, DC, Feb. 1967.
  • Grimwood, J. M., et al., Project Gemini technology and operations - A chronology, NASA, NASA SP-4002, Wash., DC, 1969.
Diagram of Gemini Capsule

Diagram of the Gemini capsule. (Courtesy of NASA History Office.)

Gemini Books Online

On The Shoulders of Titans: A History of Project Gemini - NASA History Office
Project Gemini Technology and Operations - A Chronology - NASA History Office
Gemini Summary Conference - NASA History Office

Gemini Home Page
More Gemini Diagrams - NASA History Office

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