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Air Force Taurus T-05 
Taurus

Taurus is a four stage solid fuel expendable that combines a Peacekeeper (MX) ICBM-type first stage with three Orbital Sciences Pegasus upper stages.  A Pegasus avionics assembly, mounted atop the upper stage,  provides vehicle guidance and control. 

Three variants are available.  For DoD missions, ARPA/Air Force Taurus (Taurus 1000-series)  is powered by a surplus Thiokol Peacekeeper first stage.   For commercial launches, Taurus-120 (Taurus 2000-series) uses a Thiokol Castor-120 in place of the Peacekeeper stage.  Another commercial variant, Taurus XL (Taurus 3000-series), is also available.  Taurus XL uses a Castor-120 first stage and three Pegasus XL upper stages.  ARPA Taurus uses a 1.6 meter diameter payload fairing.  The commercial variants can use 1.6 or 2.34 meter fairings. 

Thiokol's Castor-120 is a commercial derivative of the Peacekeeper first stage that also powered Lockheed Martin's Athena.  Castor-120 has a less aggressive thrust profile than Peacekeeper, with less maximum thrust and a longer burn time.  Orbital Sciences calls the Taurus first stage "Stage-0" in order to keep the Pegasus stage names, "Stage-1, 2, and 3".  An optional Star 37 fourth stage can also be used for higher energy missions.   

The first Taurus demonstration flight, for ARPA, occurred in 1994.  Taurus did not fly again until 1998, and it has flown infrequently since. The sixth launch failed to reach orbit in 2001 when a second stage thrust vector control actuator stuck for a few seconds at the start of the stage burn. The Taurus stages all fired, but the momentary loss of directional control caused a velocity shortfall.   Taurus performed a successful flight in 2004, but no more launches took place until 2009.

Taurus lifts off from a pedestal platform equipped with a fallback umbilical and minimal support equipment.  All previous launches have taken place from Vandenberg AFB SLC 567E.  Other potential Taurus launch sites include Vandenberg AFB SLC 8 (California Launch Facility); Wallops Island, Virginia; Kodiak Island, Alaska, and Cape Canaveral SLC 46. 

t8.jpg (4670 bytes)Taurus Fails

The eighth Taurus, a four-stage XL variant identified as a Taurus 3110 in Orbital's catalog, failed to orbit NASA's Orbiting Carbon Observatory (OCO) on February 24, 2009.  The rocket's payload fairing failed to separate when commanded to separate after the rocket's Orion 50SXLT second stage (Stage 1) motor completed its burn.  

The failure occurred nearly 3 minutes after Taurus 008's 09:55 UTC liftoff from Vandenberg AFB SLC 576 East, but Taurus flew on with the fairing still attached for another 9.5 minutes.  All four stages completed their burns, but the fairing mass caused the upper stage and payload to fall short of orbital velocity.    They reportedly reentered somewhere near Antarctica.

It was the second Taurus failure in eight flights.    The launch was the first for Taurus since 2004.  Two of the last three Taurus missions have failed to reach orbit.  


t9.jpg (5089 bytes)Taurus XL Fails

Orbital Sciences' ninth Taurus rocket failed to deliver NASA's Glory satellite to orbit on March 4, 2011.  It was the rocket's second consecutive failure, the prior failure having occurred in 2009.  Failure of the clamshell payload fairing to separate was the cause of both of the consecutive failures.  In both cases, the payload fairing's extra mass caused the rocket's fourth stage and payload to fall short of orbital velocity.  Even if orbit had been achieved, the satellite would have been trapped in its fairing.  The lost mission cost a reported $424 million.

Taurus XL "T9", a 3110 model with a Castor 120 "Zero Stage" topped by three Pegasus XL stages, lifted off from Vandenberg AFB SLC 576 East at 10:09 UTC.  Six seconds after the third ("Stage 2") stage ignited just under three minutes into the flight, the payload fairing failed to separate.   The upper stages continued to fire as velocity gradually fell short of the planned result.  The upper stage/payload composite likely reentered into the Southern (Pacific) Ocean.

After 2009's "T8" Taurus failure destroyed NASA's Orbiting Carbon Observatory, Orbital spent two years re-designing the payload fairing separation system, replacing a hot-gas pressurization system with a cold gas system. 

Glory would have mapped aerosol particulates in the atmosphere, part of an effort to improve climate change models.

NASA's last three attempts to use Taurus have failed.

Taurus first flew in 1994.  The all-solid fuel rocket's first five launches were successful, but the sixth, in 2001, failed when a second stage thrust vector control actuator briefly stuck.  NASA lost its QuickTOMS satellite in that mishap, which also destroyed Orbview-4.  The seventh Taurus launch, in 2004, successfully orbited Taiwan's ROCSAT-2.  Five years passed without a Taurus flight before the T8 failure.

New Taurus

After the Glory launch failure, Orbital decided to re-brand its troubled launch vehicle. Future Taurus vehicles would be named "Minotaur C".  The change heralded the adoption of Minotaur avionics for flight guidance and control.

Vehicle Configurations

  LEO Payload
(metric tons)
400 km x 28 deg
LEO Payload
(metric tons)
400 km x 98 deg
Configuration LIftoff
Height
(meters)
Liftoff
Mass
(metric tons)
Taurus 1110 1.150 t 0.820 t MX Stg1 + Orion 50S + Orion50 + Orion38 26 m 73.00 t
Taurus 2110 1.259 t 0.889 t Castor 120 + Orion 50SG + Orion50 + Orion38 + 1.6mPLF 27 m 73.03 t
Taurus 2210 1.047 t 0.695 t Castor 120 + Orion 50SG + Orion50 + Orion38 + 2.34mPLF 27 m 73.03 t
Taurus 3110 1.458 t 1.054 t Castor 120 + Orion 50SXLG + Orion50XL + Orion38 + 1.6mPLF 32 m 77.00 t
Taurus 3210 1.276 t 0.882 t Castor 120 + Orion 50SXLG + Orion50XL + Orion38 + 2.34mPLF 32 m 77.00 t

Vehicle Components

  Stg 0
(MX Stg 1)
Stg 0
Castor 120
Stg 1
(Orion 50S(G)
Stg 2
(Orion 50)
Stg 2
(Orion50XL)
Stg 3
(Orion38)
Payload
Fairing
Diameter (m) 2.38 m 2.38 m 1.27 m 1.28 m 1.28 m 0.97 m 1.6 m/2.34 m
Length (m) 12.8 m 12.8 m 8.9 m 2.64 m 3.58 m 2.08 m ~4 m/~6 m
Propellant Mass (tonnes)   48.96 t 12.147 t 3.024 t 3.925 t 0.770 t  
Empty Mass (tonnes)   4.211 t 1.873 t 0.346 t 0.406 t 0.203 t  
Total Mass (tonnes) 53.02 t 53.171 t 14.020 t 3.370 t 4.331 t 0.973 t ~0.3 t/~0.3 t
Engine   Castor 120 Orion 50S(G) Orion 50 Orion50 Orion38  
Engine Mfgr ATK ATK ATK ATK ATK ATK  
Fuel Solid HTPB Solid HTPB Solid HTPB Solid HTPB Solid HTPB Solid HTPB  
Oxidizer      
     
Thrust
(SL tons)
     
     
Thrust
(Vac tons)
224.796 t 164.665 t 48.073 t 11.75 t 15.653 t 3.525 t  
ISP (SL sec)      
     
ISP (Vac sec)   282 s 285 s 290 s 290 s 287 s  
Burn Time (sec) 60.9 s 82.5 t 73 s 75.1 s 73 s 68.5 s  
No. Engines/Motors 1 1 1 1 1 1  
Example Launch Timeline
Air Force Taurus to LEO Orbit from Vandenberg
==========================================================
Event                 Time   Altitude  Range  Velocity
                      (sec)  (nmi)     (nmi)  (ft/sec)
-------------------------------------------------------------
S0 Start               0.0     0.0       0          0
S0 Sep/S1 Start       60.9    20.2      21      7,016
S1 Burnout           140.5    92.1     141     14,940
S1 Sep               145.6    97.7     152     14,870
S2 Start             147.7   100.0     157     14,504
Fairing Sep          152.7   105.5     167     14,706
S2 Burnout           229.0   174.4     371     20,732
S2 Sep               531.9   307.3   1,307     19,595
S3 Start             542.9   309.3   1,341     19,579
S3 Burnout           617.2   314.0   1,574     24,834
Payload Sep          732.0      
==========================================================
Example Launch Timeline
Commercial/Taurus-120 to LEO Orbit from Vandenberg 
==========================================================
Event                 Time   Altitude  Range  Velocity
                      (sec)  (nmi)     (nmi)  (ft/sec)
-------------------------------------------------------------
S0 Start               0.0     0.0       0          0
S0 Sep/S1 Start       81.5    21.0      30      6,824
S1 Burnout/Sep       154.7    61.0     147     14,974
S2 Start             166.8    69.0     175     14,885
Fairing Sep          169.8    71.0     182     15,010
S2 Burnout           247.5   117.0     405     21,726
S2 Sep/S3 Start      635.0   249.0   1,685     20,759
S3 Burnout           704.0   250.0   1,901     25,305
Payload Sep          764.0   250.0   2,116     25,305 
==========================================================
TAURUS LAUNCH LOG
=============================================================================== 
03/13/94 Taurus (Darpa)   T1  STEP 0/DARPASAT                 VA 576E   LEO/P
02/10/98 Taurus 120       T2  GFO 1/Orbcomm 3,4               VA 576E   LEO/P
10/03/98 Taurus (Darpa)   T3  STEX (NRO)                      VA 576E   LEO/P  
12/21/99 Taurus 120       T4  KOMPSAT/ACRIMSAT                VA 576E   LEO/S 
03/13/00 Taurus (Darpa)   T5  Multispectral Thrm Imager       VA 576E   LEO/P
09/21/01 Taurus 2110      T6  Orbview4/QuikTOMS               VA 576E  [FTO][1]
05/20/04 Taurus XL 3210   T7  Rocsat 2                  0.8   VA 576E   LEO/S
02/24/09 Taurus XL 3110   T8  OCO                       0.407 VA 576E  [FTO][2]
03/04/11 Taurus XL 3110   T9  Glory                     0.54  VA 576E  [FTO][3]
-------------------------------------------------------------------------------
[1] Stg 2 TVC actuator stuck for a few seconds at start of Stg 2 burn.
[2] Payload fairing failed to separate.
[3] Payload fairing failed to separate.  Planned LEO/S.
===============================================================================
Reference:  Taurus Payload Users Guide, OSC, March 2006
Updated March 10, 2017