Project Gemini

Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between Projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966.

Its objective was to develop techniques for advanced space travel, notably those necessary for Apollo, whose objective was to land humans on the Moon. Gemini missions included missions long enough for a trip to the Moon and back, the first American spacewalks, and new orbital maneuvers including rendezvous and docking. All manned Gemini flights were launched from Cape Canaveral, Florida atop Titan II GLV boosters.

Spacecraft

NASA selected McDonnell Aircraft, which had been the prime contractor for the Project Mercury capsule, to build the Gemini capsule in 1961 and the first capsule was delivered in 1963. The spacecraft was 19 feet long and 10 feet wide with a launch weight of 8,490 pounds. The Gemini capsule first flew with a crew on March 23, 1965.[3]

Gemini was the first manned spacecraft to include an onboard computer, the Gemini Guidance Computer,[4] to facilitate management and control of mission maneuvers. Unlike the Mercury, it used ejection seats, in-flight radar and an artificial horizon—devices borrowed from the aviation industry.

A major difference between the Gemini and Mercury spacecraft was that Mercury had all systems other than the reentry rockets situated within the capsule, most of which were accessed through the astronaut's hatchway. In contrast, Gemini housed power, propulsion, and life support systems in a detachable Equipment Module located behind the Reentry Module, which made it similar to the Apollo Command/Service Module design. Many components in the capsule itself were reachable through their own small access doors.

The original intention was for Gemini to land on solid ground instead of at sea, using a Rogallo wing paraglider rather than a parachute, with the crew seated upright controlling the forward motion of the craft. To facilitate this, the paraglider 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. However, this design was ultimately dropped, and parachutes were used to make a sea landing as in Project Mercury. However, 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.

Early short-duration missions had their electrical power supplied by batteries; later endurance missions used the first fuel cells in manned spacecraft.

Unlike Mercury, which could only change its orientation in space, the Gemini spacecraft could translate in all six directions, and alter its orbit. It was designed to dock with the Agena Target Vehicle, which had its own large rocket engine which was used to perform large orbital changes.

The Gemini program cost $5.4 billion.

Team

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 prime contractor was McDonnell Aircraft, which had also been the prime contractor for the Project Mercury capsule.

In addition, astronaut Gus Grissom was heavily involved in the development and design of the Gemini spacecraft. He writes in his posthumous 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 of his efforts on the upcoming Gemini Program.

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.

Guenther Wendt was a McDonnell engineer who supervised launch preparations for both the Mercury and Gemini programs. His team was responsible for completion of the complex pad close-out procedures just prior to spacecraft launch, and he personally closed the hatches before flight. The astronauts appreciated his taking absolute authority over, and responsibility for, the condition of the spacecraft and developed a good-humored rapport with him.