Gemini 1

Gemini 1

Launch of Gemini 1
Mission type	Test flight
Operator	NASA
COSPAR ID	1964-018A
SATCAT №	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	155 kilometers (84 nmi)
Apogee	271 kilometers (146 nmi)
Inclination	32.5 degrees
Period	88.76 minutes
Epoch	April 10, 1964
---- Project Gemini Gemini 2 →

Gemini 1 was the first unmanned test flight of the Gemini spacecraft in NASA's Gemini program. Its main objectives were to test the structural integrity of the new spacecraft and modified Titan II ICBM. 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.

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 orbit for almost 64 orbits until the 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.

Spacecraft

Gemini Spacecraft Number 1 was built specifically for an unmanned mission. Crew life support systems were replaced with ballast to approximate the weight of a crewed spacecraft. Four large holes were drilled in the capsule's ablative heat shield to ensure the spacecraft was destroyed during reentry. In place of the crew couches were measuring equipment that relayed telemetry measuring the pressure, vibration, acceleration, temperature, and structural loads during the short flight.

As with any new spacecraft, there were problems at first during system testing, and also the rocket ran into problems, as the Air Force had yet to make the Titan II totally reliable as an ICBM, let alone as a manned launch vehicle. One instance was where a short circuit was discovered in the second stage due to the insulation being cut by a defective clamp. Several more were found with the same problem meaning that 1,500 clamps had to be replaced.

However after several months of testing the launch vehicle and spacecraft were ready for launch. Due to the hypergolic propellants used in the Titan II, the launch lacked the red flame like appearance of a Saturn launch.

Mission highlights

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.

The spacecraft achieved orbit five and a half minutes after launch. The only problem found was that the launch vehicle had provided a bit too much speed and put the spacecraft into an orbit with an apogee of 320 kilometers (170 nmi) instead of the planned 299 kilometers (161 nmi).

Four hours and 50 minutes later, after three orbits, the mission was completed. There were no plans to separate the Titan II second stage, so the retrorockets could not be fired. But this was not necessary, as the high drag caused by the attached rocket stage, plus the low 160-kilometer (86 nmi) perigee, would cause the spacecraft to reenter by itself after an expected three and a half days. However, the slightly higher than planned orbit caused it to stay up for almost four days. It was tracked by the Manned Space Flight Network until it reentered over the South Atlantic, midway between South America and Africa. The Gemini 1 mission was supported by the following U.S. Department of Defense resources: 5,176 personnel, 11 aircraft and three ships.

Instrument pallets

• Gemini1 pallets.jpg

  Gemini 1 Instrument Pallets (NASA)

• Gemini1 right pallet.jpg

  Gemini 1 Right Pallet (NASA)

• Gemini1 left pallet.jpg

  Gemini 1 Left Pallet (NASA)

References

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

External links

• On The Shoulders of Titans: A History of Project Gemini