Gemini 1

Gemini 1
Gemini 1.jpg
Launch of Gemini 1
Mission typeTest flight
Mission duration4 hours 50 minutes
Distance travelled1,733,541 miles (2,789,864 km)
Orbits completed63
Spacecraft properties
SpacecraftGemini SC1
Launch mass7,026 pounds (3,187 kg)
(11,400 pounds (5,170 kg) with 2nd stage)
Start of mission
Launch dateApril 8, 1964, 16:01:01.69 (1964-04-08UTC16:01:01Z) UTC
RocketTitan II GLV, s/n 62-12556
Launch siteCape Kennedy LC-19
End of mission
DisposalUncontrolled reentry
Decay dateApril 12, 1964, 15:00:00 (1964-04-12UTC16Z) UTC
Landing siteMiddle of South Atlantic Ocean
Orbital parameters
Reference systemGeocentric
RegimeLow Earth orbit
Perigee altitude84 nautical miles (155 km)
Apogee altitude146 nautical miles (271 km)
Inclination32.5 degrees
Period88.76 minutes
EpochApril 10, 1964[1]

Gemini 1 was the first mission in NASA's Gemini program.[2] An uncrewed test flight of the Gemini spacecraft, its main objectives were to test the structural integrity of the new spacecraft and modified Titan II launch vehicle. It was also the first test of the new tracking and communication systems for the Gemini program and provided training for the ground support crews for the first manned missions.[3]

Originally scheduled for launch in December 1963, difficulties in the development of both the spacecraft and its booster caused four months of delay. Gemini 1 was launched from Launch Complex 19 at Cape Kennedy (now Canaveral), Florida on April 8, 1964. The spacecraft stayed attached to the second stage of the rocket. The mission lasted for three orbits while test data were taken, but the spacecraft stayed in space for almost 64 orbits until its orbit decayed due to atmospheric drag. The spacecraft was not intended to be recovered; in fact, holes were drilled through its heat shield to ensure it would not survive re-entry.


Project Gemini was conceived as a bridge between America's single-seat Project Mercury and the three-seat Project Apollo. With a design largely extrapolated from its predecessor,[4]:71 the Gemini spacecraft would allow two astronauts to conduct the maneuvers inherent in Apollo's lunar mission: rendezvous, docking, and changing of orbit. Moreover, Gemini would support astronauts in space for extended flights, approximating the expected length of the Apollo missions.[4]:55–74

Its two-person capacity and greater capabilities meant that Gemini would be a substantially heavier spacecraft than Mercury had been — too heavy to be lofted into orbit by Mercury's Atlas rocket. A replacement was needed. The newly developed Titan II ICBM (which had also been tapped by the Air Force for its X-20 spaceplane project) was an attractive replacement. It had a thrust some two and a half times that of the Atlas, a far simpler mechanical construction, and the ability to store propellants indefinitely. Moreover, the Titan II's propellants mixed less violently than those of Atlas meaning a booster explosion, should it happen, would be less violent. This made obsolete the heavy escape tower used in the Mercury program; instead, ejection seats could be used.[4]:41–42

The primary goal of the first Gemini mission was to flight test the modified Titan II launch vehicle and the basic structural soundness of the Gemini capsule under launch and orbital conditions. Consequently, the first Gemini capsule could be a largely boilerplate structure.[4]:181 Secondary goals of the mission included testing the remote guidance systems, the Titan's redundancy systems, and evaluation of the Gemini-Titan malfunction detection system.[5]

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