Shuttle motor test is successful

01 June 2001

A full-scale Space Shuttle Reusable Solid Rocket Motor was test fired for 123.2 seconds Thursday, May 24, in Promontory, Utah, at Thiokol Propulsion. ""The test went smoothly and an initial look at the data indicates all objectives were achieved,"" said Steve Cash, chief engineer for the Reusable Solid Rocket Motor Project Office at NASA's Marshall Space Flight Center in Huntsville, Ala.

The test is part of the flight qualification process of a new insulation design on the motor's nozzle to case joint that will improve flight safety and helps reduce costs on the motor.

Support motors are used to evaluate, validate and qualify changes proposed for the Shuttle's Reusable Solid Rocket Motor. The motor tested was built using the same controls and documentation requirements as that of flight motors. On this motor, there were 93 objectives and a total of 576 instrumentation channels being tested. The two-minute test duration was the same length of time that the motors perform during Shuttle flights.

There were four major certification objectives for the test of Flight Support Motor-9. One of the more important tests was a change in insulation design on the nozzle-to-case joint J-leg. The proposed design change improves the thermal barrier protecting the O-rings on the motor by eliminating polysulfide, a putty-like material applied to the joint surface as the motor is assembled. The new design incorporates a J-joint - a joint shaped like a J - made of rubber for a better seal and a carbon fiber braided rope.

The rope, which is downstream of the J-joint, is another safety addition because it absorbs heat should gas seep past the joint. The new design will enhance the primary thermal barrier and will add another thermal barrier with the rope.

The upgrade is slated to fly on the Shuttle in late 2004.

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