Among my earliest memories was sitting in front of the television when I was maybe three or four years old to watch the launch of a Gemini mission (see “When I Thought My Dad Was an Astronaut“).  That launch coupled with a steady diet of space-related science fiction shows on at the time (classics like Lost in Space, Space Angel, Fireball XL5 and The Thunderbirds to name just a few) sparked my interest in space exploration which continues strong to this very day.

A 1964 drawing comparing NASA’s manned spacecraft: Apollo (top), Gemini (middle) and Mercury (bottom). In the lower left is a comparison of these programs’ launch vehicles: (left to right) The Saturn V, Titan II and Atlas. (NASA)

On an April morning in 1964, the first unmanned test flight of America’s Gemini program was launched.  While it is highly unlikely that this was the launch I recall watching (I do not think my parents even owned a TV at this point never mind that I was only two years old), it set the stage not only for the first manned Gemini mission in less than a year but for the United States’ push towards the Moon.  The purpose of the Gemini program was to develop the technology and techniques needed to fulfill President Kennedy’s goal of landing a man on the Moon by 1970.  While the Mercury program provided important information on how to get a single human into space, survive for periods of several hours while performing simple tasks and return safely home, the Mercury spacecraft was simply too small and its capabilities too limited to prepare us for the Moon.

NASA planners recognized this and on December 7, 1962 announced the Mercury Mk II program which was renamed Gemini on January 3, 1963.  The major objectives of the program were:

– Demonstrate that humans and their equipment can survive up to two weeks in space
– Demonstrate rendezvous and docking techniques in orbit
– Demonstrate the technology and techniques needed to perform EVAs (Extra-Vehicular Activities)

Meeting all of these objectives was necessary if Apollo were to be successful.

A cutaway drawing of the Gemini spacecraft. (NASA)

Gemini was a two-man spacecraft that was roughly conical in shape with a base diameter of 3.3 meters and stood 5.8 meters tall.  It consisted of two major sections: The first was the reentry module, which housed the crew in orbit and returned them to Earth, and the second was an adapter section.  The adapter section, which connected the reentry module to the launch vehicle, consisted of a retrograde section which housed the retrorockets to start the descent to Earth and an equipment section which housed in-orbit propulsion systems, life support, power systems and all other equipment not needed for the return to Earth.  With a typical launch mass of up to 3,700 kilograms or more (over twice that of the Mercury spacecraft), Gemini needed a modified Titan II ICBM called the Titan II GLV (Gemini Launch Vehicle) to get into orbit.

Diagram showing the major components of the Gemini-Titan II. Click on image to enlarge (NASA)

Many modifications were needed to man-rate the two-stage Titan II as well as smooth out its performance to safely carry men into orbit.  In fact one of the main objectives of this first unmanned Gemini test flight was to verify the performance of the Titan II GLV in addition to testing the structural integrity of the Gemini spacecraft as well as providing training for the ground support and tracking crews.  The mission of Gemini 1 was simply to get into orbit and provide three orbits’ worth of information on spacecraft performance.  No life support system was carried and in place of the astronauts were a pair of instrument pallets.  The Gemini 1 spacecraft would never separate from the second stage of the Titan II once in orbit and no recovery was planned.  In fact four large holes were purposely drilled into the reentry module’s ablative heat shield so that it would burn up with the rest of the spacecraft when its orbit naturally decayed three and a half days after launch.

Diagram showing the placement of instrument pallets that were carried in place of the astronauts on the Gemini 1 test flight. Click on image to enlarge. (NASA)

The 3,187-kilogram Spacecraft 1 arrived at Cape Canaveral on October 4, 1963 and was mated to the GLV-1 launch vehicle, Titan II Serial No. 62-12556, on March 5, 1964.  Gemini 1 lifted off from Launch Complex 19 on April 8, 1964 at 11:00 EST.  The Gemini 1 spacecraft and its spent Titan II second stage, with a total in-orbit mass of about 5,200 kg, was successfully placed into 160.3 by 320.3 kilometer orbit – slightly higher than planned.  All mission objectives were met after 4 hours 50 minutes in orbit.  Tracking of Gemini 1 continued until its orbit decayed four days later over the South Atlantic where the vehicle was destroyed.

The launch of Gemini 1 on April 8, 1964. (NASA)

While there were nine more months of work before the second unmanned test flight would fly (see “50 Years Ago Today: The Launch of Gemini 2“), Gemini 1 was an excellent start to America’s new manned space program.


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Related Reading

“50 Years Ago Today: The Launch of Gemini 2”, Drew Ex Machina, January 19, 2015 [Post]

“When I Thought My Dad Was An Astronaut”, Drew Ex Machina, July 1, 2014 [Post]


General References

Barton C. Hacker and James M. Grimwood, On the Shoulders of Titans: A History of Project Gemini, SP-4203, NASA History Division, 1977

David J. Shayler, Gemini: Steps to the Moon, Springer-Praxis, 2001