Minotaur-C (Minotaur Commercial), formerly known as Taurus or Taurus XL, is a four stage solid fueled launch vehicle built in the United States by Northrop Grumman and launched from SLC-576E at California's Vandenberg Air Force Base. It is based on the air-launched Pegasus rocket from the same manufacturer, utilizing a "zeroth stage" in place of an airplane. The Minotaur-C is able to carry a payload of around 1,350 kg into a low Earth orbit.
Taurus 1110 preparing to launch STEP 0 on March 13, 1994.
|Function||Orbital launch vehicle|
|Manufacturer||Orbital Sciences, Orbital ATK, Northrop Grumman|
|Country of origin||United States|
|Cost per launch||US$40-50 million |
|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||Vandenberg SLC-576E|
|First flight||13 March 1994, 22:32 UTC|
USA 101/USA 102
|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|
First launched in 1994, it has successfully completed seven out of a total of ten military and commercial missions. Three of four launches between 2001 and 2011 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 latest two launch failures resulted in losses totalling $700 million for NASA (excluding the cost of the rockets themselves). The Taurus launch vehicle was subsequently rebranded in 2014 as Minotaur-C, which incorporates new avionics based on those used by the Minotaur family of rockets. After a six years pause, the rocket successfully returned to flight in 2017 as Minotaur-C.
The Minotaur-C's first stage, an Orbital ATK Castor 120, 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, so far unused.
|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|
|3||Castor-120||Orion 50SXLT||Orion 50XLT||N/A||Star-37FM||Star-37|
List of launchesEdit
|Date/Time (UTC)||Vehicle type||Launch site||Payload||Result|
|1||March 13, 1994
|ARPA Taurus||VAFB SLC-576E||STEP Mission 0 & DARPASAT||Success|
|2||February 10, 1998
|Commercial Taurus, 92" payload fairing and 63" dual payload attach fitting||VAFB SLC-576E||GFO and ORBCOMM (Satellites 11,12)||Success|
|3||October 3, 1998
|Air Force Taurus Configuration, 63" fairing, Peacekeeper Stage 0||VAFB SLC-576E||Space Technology Experiment (STEX) for National Reconnaissance Office (NRO)||Success|
|4||December 21, 1999
|Model 2110, 63" fairing, Castor 120 Stage 0||VAFB SLC-576E||KOMPSAT and ACRIMSAT||Success|
|5||March 12, 2000
|Air Force Taurus Configuration, 63" fairing, Peacekeeper Stage 0||VAFB SLC-576E||Multispectral Thermal Imager (MTI)||Success|
|6||September 21, 2001
|Model 2110, 63" fairing, Castor 120 Stage 0||VAFB SLC-576E||Orbview-4/QuikTOMS||Failure|
|7||May 20, 2004
|Model 3210, 92" fairing, Castor 120 Stage 0||VAFB SLC-576E||ROCSAT-2||Success|
|8||February 24, 2009
|Model 3110, 63" fairing, Castor 120 Stage 0||VAFB SLC-576E||Orbiting Carbon Observatory ||Failure|
|9||March 4, 2011
|Model 3110, 63" fairing, Castor 120 Stage 0||VAFB SLC-576E||Glory, KySat-1, Hermes, and Explorer-1 [PRIME]||Failure|
|10||October 31, 2017
|Model 3210, 92" fairing, Castor 120 Stage 0||VAFB SLC-576E||SkySat x 6, Flock-3m x 4||Success|
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.
Orbiting Carbon ObservatoryEdit
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. The replacement satellite, Orbiting Carbon Observatory-2, was launched July 2, 2014 aboard a Delta II rocket.
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.
A continued investigation eventually revealed that sub-standard parts with falsified test results were the likely cause of both of the OCO and Glory fairing failures.
The upper stages of the Minotaur-C are used by the boost vehicle of the Ground-Based Interceptor, the anti-ballistic missile component of the U.S. Missile Defense Agency's Ground-Based Midcourse Defense system.
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The Orbital Boost Vehicle, developed for the US military’s Ground Based Interceptor program, uses the upper stages of the Taurus
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