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astronautix.com SRB


Designer: Thiokol. Used on stages: Shuttle SRB. Used on launch vehicles: Barbarian MDD, IHLLV, Shuttle, Shuttle C. Gross Mass: 589,670 kg. Empty Mass: 86,183 kg. Propellants: Solid Thrust(vac): 1,174,713 kgf. Thrust(vac): 11,519.80 kN. Isp: 269 sec. Isp (sea level): 237 sec. Burn time: 124 sec. Diameter: 3.7 m. Length: 38.5 m. Chambers: 1. Country: USA. Status: In Production. First Flight: 1981. Last Flight: 1998. Flown: 186. References: 480 .

The decision to use segmented solid rocket boosters for the compromised space shuttle design, and the selection of Thiokol as the contractor, was fraught with political overtones. Aerojet in particular offered to build monolithic non-segmented SRB's from the Florida facility it had built in the 1960's for its 260 inch motors. The monolithic approach completely eliminated a number of potential failure modes, and should have resulted in considerably lower cost. One of these failure modes resulted in the Challenger disaster.

When the award to Thiokol was announced, Lockheed was so upset that they lodged a formal protest, but nothing ever came of it. Many years later, it was learned from a source close to the original source selection board that Thiokol was ranked fourth out of four by a wide margin. So, a new board had been convened, and strangely enough, Thiokol won. Many in the losing teams felt that this just may have been influenced by the fact that the Chairman of the Senate Space Committee was the senior senator from Utah. The selection of Thiokol was said to have been ordered directly from the Nixon White House. A similar situation occurred after the Shuttle disaster, with the decision, despite all that had happened, to continue with Thiokol's redesigned motors in lieu of solutions from other manufacturers (such as the cancelled ASRM).


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Last update 12 March 2001.
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