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Launch of Gemini 1
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Mission type | Test flight |
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Operator | NASA |
COSPAR ID | 1964-018A ![]() |
SATCAT no. | 782 |
Mission duration | 4 hours 50 minutes |
Distance travelled | 2,789,864 kilometers (1,733,541 mi) |
Orbits completed | 63 |
Spacecraft properties | |
Spacecraft | Gemini SC1 |
Manufacturer | McDonnell |
Launch mass | 3,187 kilograms (7,026 lb) 5,170 kilograms (11,400 lb) (with 2nd stage) |
Start of mission | |
Launch date | April 8, 1964, 16:01:01.69 (1964-04-08UTC16:01:01Z) UTC |
Rocket | Titan II GLV, s/n 62-12556 |
Launch site | Cape Kennedy LC-19 |
End of mission | |
Disposal | Uncontrolled reentry |
Decay date | April 12, 1964, 15:00:00 (1964-04-12UTC16Z) UTC |
Landing site | Middle of South Atlantic Ocean |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth orbit |
Perigee altitude | 155 kilometers (84 nmi) |
Apogee altitude | 271 kilometers (146 nmi) |
Inclination | 32.5 degrees |
Period | 88.76 minutes |
Epoch | April 10, 1964[1] |
Gemini 2 → |
Gemini 1 was the first flight of the Gemini spacecraft in NASA's Gemini program.[2] An uncrewed test flight, 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]
Gemini 1 was launched from Launch Complex 19 at Cape 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, the ability to store propellants indefinitely. Moreover, the Titan II's fuels 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. As such, 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]
Gemini Spacecraft Number 1 was built specifically for the uncrewed mission. Most internal systems were replaced with dummies and ballast approximating the weight and balance of the crewed spacecraft. In place of the crew couches, two sets of instrument pallets were installed for the relaying via telemetry of the pressure, vibration, acceleration, temperature, and structural loads experienced during the short flight. A spacecraft heat shield was installed, but four large holes were drilled in it to ensure Gemini 1 was destroyed during reentry.[4]: 181
Even with the simplified systems, this first Gemini encountered delays several weeks of delay in testing. Nevertheless, it was not the spacecraft that caused the launch date, originally planned for December 1963, to slip. Rather, it was the testing and man-rating of the Titan II launch vehicle. Assembled on May 21, 1963, the first Titan-Gemini launch vehicle required comprehensive testing and retesting, and it until October that it was ready for transport to the launch site — where considerable preparation still had to be done.[4]: 185 Moreover, there was concern that the Titan II produced too much vertical oscillation or POGO to be usable at all, and consideration was given to using the Saturn I rocket instead, at least for the first missions. However, on November 1, 1963, the Air Force flew a Titan II with standpipes in its oxidizer lines and mechanical accumulators in its fuel lines, which suppressed the pogo effect.[6]
Inefficient project management threatened to further delay the first Gemini launch, which by November had already been pushed back to February 28 1964. Gemini Manager Charles Mathews united the several disparate teams into a single Gemini Launch Vehicle Coordination Committee with clearly defined management and communication channels.[4]: 188 This measure ensured that no more time would be lost due to uncertain authority, duplicated effort, or conflicting decisions. Still, issues that arose during testing caused the launch date to slip further.[4]: 189 The Titan II booster was not ready for final readiness testing until March 3, 1964, the same day that Gemini Spacecraft Number 1 arrived at the launch complex for mating with its booster.[4]: 190 Faulty test equipment caused a further delay of two weeks. By late March, all serious hurdles cleared, Gemini 1's launch date was set for April 7.[4]: 195 The resolution of a failure in the secondary autopilot caused one last day of delay. Finally, by noon of the seventh, Gemini 1's Mission Review Board determined unanimously that all systems were cleared for flight.[4]: 197
After a flawless countdown, Gemini 1's Titan II booster lifted off from Cape Canaveral's Launch Complex 19[4]: 194 at 11:00:01 EDT, April 8, 1964.[4]: 197 The first stage was jettisoned after two and a half minutes with the rocket 64 kilometers high and 91 kilometers downrange. At that moment there was an unexpected three second loss of signal from the craft. It was later determined that this brief communications blackout was caused by charged ions from the separation and startup of the second stage, similar to the blackout during spacecraft reentry. All subsequent Gemini flights would have the same brief blackout.[7]
The spacecraft achieved orbit five and a half minutes after launch. The launch vehicle had imparted an excess 7 meters (24 feet) per second of velocity to the Gemini 1, placing the spacecraft into an orbit with an apogee of 320 kilometers (170 nmi) instead of the planned 299 kilometers (161 nmi). This lengthened Gemini 1's lifespan from the planned three and a half days to four.[4]: 199
The formal mission of Gemini 1 was over long before that. Its battery had only been designed to last a single orbit,[8] and only the first three orbits, lasting four hours and 50 minutes later, were part of the flight plan. Gemini 1 and its attached second stage were tracked by the Manned Space Flight Network until they reentered over the South Atlantic, midway between South America and Africa, on April 12, 1964 during their 64th orbit.[4]: 199
As a result of the successful flight, the Titan II was considered "man-rated" (safe for use in human spaceflight).[4]: 200 Man-rating the Gemini capsule, itself, would not be accomplished until the launch of Gemini 2, nine months later, on January 19, 1965.[4]: 209
The Gemini 1 mission was supported by the following U.S. Department of Defense resources: 5,176 personnel, 11 aircraft and three ships.[4]: Appendix G-299
This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.
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Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |