NASA’s Space Shuttle program successfully test fired its first Flight Verification Motor — a test to further validate the five-year lifespan of a Reusable Solid Rocket Motor — Thursday, Feb. 17, at a Promontory, Utah, test facility.
Shuttle Solid Rocket Motors are certified for flight for five years. The test of the four-segment motor further substantiates a certification established by NASA more than 20 years ago at the beginning of the Space Shuttle Program.
The test was performed at ATK Thiokol Inc., an Alliant Techsystems company, in Promontory, north of Salt Lake City. ATK Thiokol manufactures the Shuttle’s Solid Rocket Motor. The four right-hand segments of the flight set Reusable Solid Rocket Motor number 89, or RSRM-89, were used for the test.
The Flight Verification test allows NASA and ATK Thiokol engineers to better understand mid-life rocket motors and to gather information not typically gained from previous motor tests. Motor tests generally focus on guaranteeing that new materials meet safety requirements for the motors. The static, or stationary, test closely reproduces Space Shuttle launch and ascent conditions. The two-minute test duration is the same length of time that the motors perform during Shuttle flights.
During the test, 167 data-gathering instruments were placed on the motor to provide information on the motor’s performance. Additionally, a powerful X-ray was used to scrutinize how the motor would perform during launch and ascent. A total of 32 objectives were established for the test, including determining how the motor’s igniter — which begins combustion — performs at mid-life.
The Reusable Solid Rocket Motor is one of the four Shuttle propulsion elements, which also include the Solid Rocket Boosters, the Main Engines and the External Tank. Two Solid Rocket Boosters, each consisting of four motor segments, provide a combined thrust of some 5.8 million pounds for the Space Shuttle during the first two minutes of flight. The Boosters take the Shuttle to an altitude of 28 miles at a speed of 3,094 mph before they separate and fall into the ocean to be retrieved, then refurbished and prepared for another flight.
Each Solid Rocket Motor is divided into four segments of propellant which are each bound by a metal casing. Once the segments are joined, they become part of the left or right Booster.
“This test is just one example of the aggressive testing program NASA pursues to assure flight safety,” said Mike Rudolphi, manager of the Space Shuttle Propulsion Office at NASA’s Marshall Space Flight Center in Huntsville, Ala. “It will also allow us to gather information on how a motor performs that was built immediately prior to the flight set that will launch STS-114, NASA’s Return to Flight mission planned for May.”
Static firings of motors are part of the ongoing verification of components, materials and manufacturing processes required by the Space Shuttle program. NASA annually tests its solid rocket motors to evaluate, validate and qualify any proposed improvements or changes.
At 126 feet long and 12 feet in diameter, the Shuttle’s Reusable Solid Rocket Motor is the largest solid rocket motor ever flown and the first designed for reuse. Each motor segment is 30 feet long and filled with propellant.
The left-hand motor of the RSRM 89 set will be tested in January of 2007, according to Jody Singer, manager of the Reusable Solid Rocket Motor Project, part of the Space Shuttle Propulsion Office.
Test data will be analyzed and the results for each objective provided in a final report. Following the test, the motor’s metal casings and its nozzle components will be refurbished for reuse.
