Taurus 3210 preparing to launch ROCSAT 2 on May 20, 2004.
|Function||Orbital launch vehicle|
|Country of origin||United States|
|Height||27.9 m (91.5 ft)|
|Diameter||2.35 m (7.7 ft)|
|Mass||73,000 kg (160,000 lb)|
|Payload to LEO||1,320 kg (2,910 lb)|
|Launch sites||Wallops Island
LC-576E, Vandenberg AFB
|First flight||20:06 GMT, 21/12/89|
|First stage - Castor 120|
|Thrust||1,606.6 kN (361,177 lbf)|
|Specific impulse||286 sec|
|Burn time||83 seconds|
|Second stage - Taurus-1|
|Thrust||484.9 kN (109,012 lbf)|
|Specific impulse||285 sec|
|Burn time||73 seconds|
|Third stage - Pegasus-2|
|Thrust||118.2 kN (26,570 lbf)|
|Specific impulse||292 sec|
|Burn time||73 seconds|
|Fourth stage - Pegasus-3|
|Thrust||34.57 kN (7,770 lbf)|
|Specific impulse||293 sec|
|Burn time||65 seconds|
Taurus is a four stage, solid fuel launch vehicle built in the United States by Orbital Sciences Corporation. It is based on the air-launched Pegasus rocket from the same manufacturer. The Taurus rocket is able to carry a payload of around 1,350 kg into a low Earth orbit. First launched in 1994, it has successfully completed six out of a total of nine military and commercial missions. Three of the last four launches have ended in failure, including the February 24, 2009 launch of the Orbiting Carbon Observatory mission and the March 4, 2011 launch of the Glory mission. The failure of the two latest launches resulted in losses totalling $700 million for NASA (not including cost of the rockets themselves).
The Taurus first stage, a Castor 120 made by ATK (formerly Thiokol), is based on a Peacekeeper ICBM first stage. Stages 2 and 3 are Orion-50s (like the Pegasus-1 but without wings or stabilisers), and stage 4 is an Orion-38, derived from the Pegasus-3.
Different configurations are designated using a four digit code, similar to the numbering system used on Delta rockets. The first digit denotes the type of first stage being used, and whether the second and third stages use a standard or "XL" configuration. The second digit denotes the diameter of the payload fairing. The third digit denotes the type of fourth stage. The fourth digit denotes an optional fifth stage, however as of 2009, this has not been used.
|Number||First digit||Second Digit||Third Digit||Fourth Digit|
|First stage||Second stage||Third stage||Fairing diameter||Fourth stage||Fifth stage|
|1||TU-903||Orion-50ST||Orion-50T||1.60 m (63 in)||Orion-38||N/A|
|2||Castor-120||Orion-50ST||Orion-50T||2.34 m (92 in)||N/A||N/A|
List of launches
|Flight number||Date||Vehicle type||Payload||Result|
|1||March 13, 1994||ARPA Taurus||STEP Mission 0 & DARPASAT||Success|
|2||February 10, 1998||Commercial Taurus, 92" payload fairing and 63" dual payload attach fitting||GFO and ORBCOMM (Satellites 11,12)||Success|
|3||October 3, 1998||Air Force Taurus Configuration, 63" fairing, Peacekeeper Stage 0||Space Technology Experiment (STEX) for National Reconnaissance Office (NRO)||Success|
|4||December 20, 1999||Model 2110, 63" fairing, Castor 120 Stage 0||KOMPSAT and ACRIMSAT||Success|
|5||March 12, 2000||Air Force Taurus Configuration, 63" fairing, Peacekeeper Stage 0||Multispectral Thermal Imager (MTI)||Success|
|6||September 21, 2001||Model 2110, 63" fairing Castor 120 Stage 0||Orbview-4/QuikTOMS||Failure|
|7||May 20, 2004||Model 3210, 92" fairing, Castor 120 Stage 0||ROCSAT-2||Success|
|8||February 24, 2009||Model 3110, 63" fairing Castor 120 Stage 0||Orbiting Carbon Observatory ||Failure|
|9||March 4, 2011||Model 3110, 63" fairing Castor 120 Stage 0||Glory, KySat-1, Hermes, and Explorer-1 [PRIME]||Failure|
Orbview launch failure
On September 21, 2001, a Taurus XL rocket failed during launch. When the second stage ignited at T+83 seconds, a nozzle gimbal actuator drive shaft seized for approximately 5 seconds causing loss of control. The vehicle recovered and continued to fly the mission profile, but failed to reach a stable orbit and reentered near Madagascar.
OCO launch failure
On February 24, 2009, a Taurus XL rocket failed during the launch of the $270m Orbiting Carbon Observatory spacecraft. Liftoff occurred successfully at 09:55 GMT from Vandenberg Air Force Base, but data received at a later stage of the flight suggested that the fairing failed to separate. The rocket did not reach orbit, owing to the extra weight of the fairing. Launch vehicle and services for OCO are estimated at $54m. NASA canceled a contract to launch a replacement satellite, OCO-2, on a Taurus XL in February 2012.
Glory launch failure
On March 4, 2011, a Taurus XL rocket failed again during the launch of NASA's $424 million Glory climate change monitoring satellite. In total, the last two failures of the Taurus XL have resulted in payload losses worth $700 million. The reason for the failure was the same as with OCO: the payload fairing failed to separate, although the rocket's manufacturer Orbital Sciences Corporation had spent the last two years trying to fix the problem and had made several design changes to the fairing separation system. Ronald Grabe, manager of Orbital Sciences Corporation, which also built the Glory satellite itself, said the employees of his companies are "pretty devastated" because of the latest failure. The fairing was built by the Vermont Composites company, and the frangible rail pyrotechnic separation system was built by the Ensign-Bickford Company. A NASA MIB panel concluded that the failure was most likely caused by a section of the frangible rail somewhere near the nose cap failing to separate. While a root cause could not be identified, two likely causes were identified: the rubber charge holder in the frangible rail slumping due to launch acceleration and random vibration, or a failure of the frangible rail system due to it operating outside the environment for which it was tested.
- Comparison of orbital launchers families
- Antares, the OCO launcher subsequent to the Taurus, with a liquid-fuel first stage.
- Gunter Dirk Krebs. "Taurus".
- "Satellite to pinpoint sources and sinks of CO2".
- "Glory". NASA.
- "NASA launch mishap: Satellite crashes into ocean". CBS. 2011-03-04.
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- "Taurus". Encyclopedia Astronautica.
- Krebs, Gunter. "Taurus-3110". Gunter's Space Page. Retrieved 2009-03-08.
- "Fact Sheet". Taurus. Orbital Sciences Corporation. Retrieved 2009-03-08.
- "OCO". Orbital Sciences Corporation.
- "Taurus rocket nose shroud dooms another NASA satellite". Spaceflight Now, March 2011.
- International reference guide to space launch systems, Fourth Edition, p. 486, ISBN 1-56347-591-X
- Failure hits Nasa's 'CO2 hunter'
- NASA FY2009 Budget Estimates
- "Carbon-sniffing satellite faces one-year delay". Spaceflight Now. 2012-02-10.
- NASA. "Overview of the Glory Mishap Investigation Results for Public Release". NASA. Retrieved 2013-02-20.
- "GBI Orbital Boost Vehicle". globalsecurity.org.
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