Jerry Berg
Marshall Space Flight Center, Huntsville, Ala.

RELEASE:  89-2

SPACE SHUTTLE SOLID ROCKET MOTOR SLATED FOR FINAL TEST FIRING

     A full-scale static test firing of NASA's redesigned Space 
Shuttle solid rocket motor is scheduled for January 17.  The test 
will be the sixth and final such firing required to qualify the 
major design features of the redesigned solid rocket motor.

     The 126-foot-long, 1.2-million-pound Qualification Motor-8 
(QM-8) will undergo a full-duration horizontal test firing of 2 
minutes.  The 1 p.m. MST firing will take place in test bay T-97 
about 25 miles west of Brigham City.  Prior to the firing, the 
QM-8 motor will be cooled down to 40 degrees F. during a period 
of 30 days prior to the firing.  That is its lowest specified 
operating temperature and is lower than any expected motor 
temperature at launch.

     The test is part of the Shuttle motor redesign program.  The 
verification and qualification test program to certify the motor 
redesign consists of five full-duration tests, conducted prior to 
resumption of Shuttle flights last Sept. 29, and the upcoming 
test under cold-weather conditions.

     Morton Thiokol is NASA's prime contractor for the solid 
rocket motor, and the Marshall Space Flight Center in Huntsville, 
Ala., manages the motor program for NASA.

                 QUALIFICATION MOTOR FACT SHEET

     Qualification motor (QM-8) is a full-size Space Shuttle 
solid rocket motor, approximately 126 feet in length and 12 feet 
in diameter.  The motor weighs 1.2 million pounds including 1.1 
million pounds of propellant.

     The QM-8 motor will be conditioned to a mean or average bulk 
propellant temperature of 40 degrees F.  This is several degrees 
cooler than any expected motor temperature at launch and will 
demonstrate margins of safety.  The T-97 test bay, in which the 
firing will take place, can provide chilled air as low as 20 
degrees F. to cool the motor's large mass of propellant to a 40-
degree average.

     The three field joints which connect the motor segments are 
of the flight configuration, capture feature tang-and-clevis 
design with three Viton (TM) O-rings and an adhesively bonded, J-
shaped deflection relief slot at each field joint which reduces 
stresses and also increases the sealing action of the bonded 
surfaces under motor pressure.  Joint heaters, mounted around the 
motor case at each field joint location, are thermostatically 
controlled to maintain joint temperatures at a minimum of 75 
degrees F.  In addition, the igniter joint will have heaters to 
maintain a minimum of 66 degrees F. and the aft skirt will be 
conditioned with heated air to assure a minimum case-to-nozzle 
joint temperature of 75 degrees F.  These temperatures are the 
same as for a launch.

     The motor case-to-nozzle joint on QM-8 also is of the flight 
configuration, incorporating 100 radial bolts, adhesively bonded 
insulation surfaces, a shaped relief slot and an added Viton 
"wiper" O-ring designed to keep the adhesive on the insulation 
surfaces during assembly.

     None of the joints in the QM-8 motor contain intentional 
manufacturing or assembly defects.  The QM-8 motor is equipped 
with a flight design external tank attachment ring.  Three 
hydraulically actuated struts, which simulate the motor's 
connection to an external tank, are attached to the ring.  During 
the motor firing, a programmed series of dynamic loads will be 
applied through the external tank attach struts to simulate 
ignition, liftoff and flight loads.  Response of the QM-8 motor 
to those loads will be monitored by special instrumentation.

     The QM-8 motor is fitted with more than 600 instruments to 
measure acceleration, pressure, deflection, thrust, strain, 
temperature, electrical properties and other conditions.