Conference 7.286::space

    I haven't heard anything more on the Shuttle SRB, but another item
    of interest I saw in the latest issue of AW&ST said that Morton
    Thiokol's latest test of the solid fuel motors for the Delta booster
    failed.  It seems that the case ruptured (I think near a joint)
    and the motor flew from the test stand about 150 feet or so from
    the resultant explosion.  My details are regrettably vague as I
    don't have the article in front of me.  -Mike

    It blew out the head of the combustion chamber, what we model
    rocketeers call a blow-through. This blew off the top of the casing and
    ripped the engine off the test stand. 
    
    The Castor series motors are not segmented, they are poured in one
    piece. I think the test was in conjunction with the Delta II program
    but I'm not sure (and my copy of AW&ST is on its way to the USPO
    forwarding center in Muncie, In or somewhere)
    
    FWIW, it would not have 'exploded', strictly speaking. The propellant
    may have even extinguished itself when it suddenly lost chamber
    pressure. 
    
    gary

    For some reason, C-Span carried the entire press conference following
    the SRB firing a couple of nights ago. The usual array of dumb
    questions.
    
    I missed the beginning but apparently the water dousing system that
    delayed the firing earlier failed to extinguish something at head end
    of the motor. M-T reps claimed it would have no impact on the test
    results. Highlights of the conference were on the various news programs
    but it may be worthwhile checking C-Span after these event in the
    future.
    
    gary

  Are test-firings of motors ever forced to failure by doing something
extremely nasty to them?  Like leaving out the 'O' rings in the previous
design of the SRB's, or leaving air pockets between segments.  The reason
I ask is that if you try something out and it works, you don't necessarily
understand what's going on.

  Take an aircraft simulator, for instance.  You get to crash into things,
lose engines, do gear-up landings, etc.  The sorts of things that astronauts
train to be able to respond to.  Are all static motor tests just seeing
if the thing runs?

John

    re .4:  John, at least one SRB test that I know of included things
    like filed-down o-rings and missing insulation.  This was a firing
    of a subset of the "real thing".  It had only one joint and a few
    hundred pounds of propellant as I recall.
    
    I also recall (although possibly incorrectly) that some time ago,
    the problem that destroyed Challenger was reproduced.  My recollection
    is that they chilled the joint among other things and got it to
    leak.  I may be wrong here...I saw it in one source, but never saw
    confirmation anywhere else.
    
    Burns
    

    Yes, there was a firing of a subscale motor to reproduce the failure
    mechanism that destroyed Challenger. I have not seen mention of
    any other fault insertion testing but that sort of testing hasn't
    gotten much publicity in the past.
    
    gary

    Thanks for confirming the "reproduce the failure" story, Gary. 
    The other fault-insertion test was the subscale test just previous to
    this full scale test.  It was sometime during the summer, as I recall.
    It had some, but not all of the features of the redesigned booster.
    I believe, for example, that it did not have the capture latch.
    
    They had a wide variety of non-standard things.  One or more o-rings
    were (cut, filed down?), and at least one o-ring was made of a
    different substance.  (Remember, they were going to change the o-ring
    material to something different until they discovered that the new
    substance reacted with some grease that they used?...I think this
    was trying out the new material anyway).
    
    I thought I remembered something about the insulation being
    intentionally imperfect, but I am less than sure about this.
    
    Burns
    
    

RELEASE NO: 91-94  (7/1/91)

     NASA engineers will test-fire a 26-foot-long solid rocket
motor for approximately 30 seconds at 8:30 p.m. (CDT) Tuesday,
July 2, at the Marshall Space Flight Center in Huntsville, Ala.

     "The primary purpose for this test is to evaluate the
performance of non-asbestos insulation candidate materials for
NASA's solid rocket motors which fly on the Space Shuttle," said
Keith Henson, project manager for Marshall's Redesigned Solid
Rocket Motor project.

     "We currently have asbestos insulation in our solid rocket
motors; however, the future for the Shuttle Solid Rocket Motors
lies with an asbestos-free insulator," he said.

     The test motor, named the Modified NASA Motor, sits in a
specially constructed test stand in the Center's East Test Area.
The motor is 48 inches in diameter and will be loaded with two
propellant cartridges weighing a total of approximately 10,000
pounds.

     "The test bed is a good research and development facility
where we can do evaluation tests on candidate materials for
different parts of the Space Shuttle solid rocket motor," Henson
said.

     "Another objective and the reason we are firing the test
motor at night is to gather radiant heat engergy measurements from
the exhaust plume of the motor," said Tom Williams of the Marshall
Center's Solid Rocket Motor chief engineer's office. "Radiometers
and thermal imaging will provide this data that will be used to
compare the difference in heating between Redesigned Solid Rocket
Motor propellant and Advanced Solid Rocket Motor propellant.  The
night firing will enhance the radiometer measurements," he said.

     The test motor consists of one case segment, two propellant
cartridges, a forward dome loaded with inert propellant, an aft
dome segment (insulation test section), nozzle, and a laser firing
unit.  The average target pressure for the motor is 715 psi over
approximately 28 seconds.  More than 40 instruments are attached
to the motor to gather data.
 

[Unnumbered NASA Press Release]  (7/2/91)

    NASA engineers at the Marshall Space Flight Center in
Huntsville, Ala, fired a 26-foot long, solid rocket motor for full
duration of approximately 30 seconds tonight, July 2, at 9:10 p.m.
(CDT).
     The primary purpose for tonight's test was to evaluate the
performance of non-asbestos insulation candidate materials for
NASA's solid rocket motors which fly on the Space Shuttle.
Currently NASA has asbestos insulation in its solid rocket motors;
however, the future for the Shuttle Solid Rocket Motors lies with
an asbestos-free insulator, project officials said.
     The test motor, named the Modified NASA Motor, sits in a
specially constructed test stand in the Center's East Test Area.
The motor is 48 inches in diameter and was loaded with two
propellant cartridges weighing a total of approximately 10,000
pounds.
     The test motor consists of one case segment, two propellant
cartridges, a forward dome loaded with inert propellant, an aft
dome segment (insulation test section), nozzle, and a laser firing
unit.  More than 40 instruments are attached to the motor to
gather data.  Wylie Laboratories of Huntsville provided test
operations support.

 

RELEASE NO: 91-153 (8/26/91)

     NASA Engineers are scheduled to test-fire a 26-foot-long
solid rocket materials test motor for approximately 30 seconds at
8:30 p.m. (CDT) Tuesday, Aug. 27, at NASA's Marshall Space Flight
Center in Huntsville, Ala.

     The solid rocket motor test firing will be the first of five
evaluation tests of internal insulation material for NASA's
Advanced Solid Rocket Motor Project (ASRM).  The small ASRM test
motor is similar to a full-size solid rocket motor which is part
of the Space Shuttle's propulsion system.  The test has been
designated ASRM test #2.

     The test will be conducted in the Marshall Center's East Test
Area by Aerojet Corporation.  Aerojet's ASRM Division in Iuka,
Miss. is under contract to Lockheed Missiles and Space Company of
Sunnyvale, CA, the prime contractor to NASA for the new motor.

     "The primary purpose of these insulation tests is to evaluate
materials planned for use as the ASRM internal insulation.  Full-
scale static firings of NASA's Advanced Solid Rocket Motors will
be conducted later at the Stennis Space Center in Mississippi to
validate the insulation material," said Royce Mitchell, NASA's
Advanced Solid Rocket Motor project manager at the Marshall
Center.

     "The motor is 48 inches in diameter and will weigh
approximately 54,000 pounds when assembled, including two
propellant cartridges weighing a total of approximately 10,000
pounds," said Mitchell.

     The test motor is mounted in a Marshall test facility called
the Modified NASA Motor Test Stand.

     Approximately 85 measurements of temperatures, pressures,
strains and other motor characteristics will be acquired during
the firing.  The test motor consists of one steel case segment,
two solid propellant cartridges, a forward dome loaded with inert
castable inhibitor, an insulated blast tube assembly, a nozzle, an
ignitor, and a safe and arm device.  The average combustion
chamber pressure predicted for the motor is 620 psi.

     NASA successfully fired a 26-foot long, 48-inch-diameter,
subscale solid rocket motor for full duration of approximately 30
seconds Aug. 27 at 8:30 p.m. at the Marshall Center's East Test
Area.   The test performed in the Center's East Test Area is the
second in series of 10 firings which support NASA's Advanced Solid
Rocket Motor program development.

     The firing was the first test to evaluate candidate materials
for the insulation of the Space Shuttle Advanced Solid Rocket
Motor.  The test was designated ASRM Test #2.

     The test was conducted by Aerojet's ASRM Division in Iuka,
Miss., under contract to Lockheed Missiles and Space Company of
Sunnyvale, Calif., to design and build the rocket motor.  Wylie
Laboratories provided test support.

     The test motor weighs approximately 54,000 pounds and
includes two propellant cartridges weighing approximately 10,000
pounds total.  The test motor had approximately 85 instruments
located throughout the motor to measure temperatures, pressures,
strains and other motor characteristics during the firing.  The
test motor consists of one steel case segment, two solid
propellant cartridges, a forward dome loaded with inert castable
inhibitor, an insulated blast tube assembly, a nozzle, an ignitor,
and a safe and arm device.

     The next Advanced Solid Rocket Motor subscale test is
scheduled to occur in September 1991.  The Space Shuttle will
begin using the ASRM by 1996.

THIRD SUBSCALE ADVANCED SOLID ROCKET MOTOR TEST-FIRING
OCCURS AT MARSHALL SPACE FLIGHT CENTER September 26, 1991

     NASA successfully fired a 17.5-foot long, 48-inch-diameter,
subscale solid rocket motor for full duration of approximately 30
seconds Thursday night at 7:30 p.m. at the Marshall Center's East
Test Area.  The test performed in the Center's East Test Area was
the third in a series of 10 firings which support NASA's Advanced
Solid Rocket Motor program development.
     The firing was the second of five tests to evaluate candidate
materials for the nozzle of the Space Shuttle Advanced Solid
Rocket Motor.
     The test was conducted by Aerojet's ASRM Division in Iuka,
Miss., under contract to Lockheed Missiles and Space Company of
Sunnyvale, Calif., to design and build the rocket motor.  Wylie
Laboratories provided test support.
     The test motor weighs approximately 40,000 pounds and
includes two propellant cartridges weighing approximately 10,000
pounds total.  The test motor had approximately 80 instruments
located throughout the motor to measure temperatures, pressures,
strains and other motor characteristics during the firing.
     The next Advanced Solid Rocket Motor subscale test is
scheduled to occur in December.
     The Advanced Solid Rocket Motor Project will substantially
improve the safety and reliability of the Shuttle System.  The
Space Shuttle will begin using the Advanced Solid Rocket Motor by
1996.

Jim Sahli
Marshall Space Flight Center
Huntsville, Ala.


RELEASE NO: 91-181  (11/6/91)


     NASA engineers will test fire a 20-foot long, 45,000 pound
thrust solid rocket motor on Wednesday, Nov. 6, at the Marshall
Space Flight Center in Huntsville, Ala.  The test is part of the
agency's Solid Propulsion Integrity Program to better design,
build and verify solid rocket motors.
     The purpose of the Nov. 6 test is to learn more about solid
rocket motor insulation and nozzle materials and to provide
Marshall engineers additional "hands-on expertise" in solid rocket
motor technology, said Ben Goldberg, chief of the Solid Propulsion
Branch.
     Advanced motor insulation materials will be provided by the
following companies for the test:  Aerojet Corporation (Advanced
Solid Rocket Motor); Thiokol Corporation (Redesigned Solid Rocket
Motor); and Chemical Systems Division, Huntsville.  Additionally,
Thiokol Corporation will provide an experimental insulation
material.  Also, an experimental thermocouple probe, for internal
insulation measurements, provided by Wyle Laboratories, will be
tested.
     The motor, named the Modified NASA Motor, sits in a test
stand in the Center's East Test Area.  The test motor is 48 inches
in diameter and will be loaded with two propellant cartridges
weighing a total of approximately 11,500 pounds.  It will burn for
28 seconds.
     The Solid Propulsion Integrity Program originated from joint
NASA-Department of Defense-industry studies in 1984 which
identified critical shortfalls in the U. S. engineering technology
base for solid-fueled rocket motors, said Ron Nichols, manager of
Marshall's Solid Propulsion Research and Technology Office.
     The objective of the program is to provide NASA engineers
with the techniques, engineering tools and computer programs to be
able to better design, build and verify solid rocket motors.
     During the Modified NASA Motor testing, "our motor
instrumentation will allow us to monitor how the motor elements
are performing during the test," said Goldberg.  "We can take what
we learn from our computer analysis and these sub-scale tests and
have a much better idea how the new elements will act when the
full-scale test is run," he said.
     "The bottom line is that we want to test our new propulsion
ideas in test beds to make a better solid rocket motor for our
future launch systems," said Nichols.
 

Solid Propulsion Integrity Program Motor Test at MSFC

     NASA successfully fired a 20-foot long, 48-inch-diameter,
subscale solid rocket motor for full duration of approximately 28
seconds November 6 at 6:30 p.m. at the Marshall Space Flight
Center in Huntsville, Ala.  The test is part of the agency's Solid
Propulsion Integrity Program to better design, build and verify
solid rocket motors.
     The purpose of the test is to learn more about solid rocket
motor insulation and nozzle materials and to provide young
Marshall engineers additional "hands-on expertise" in solid rocket
motor technology.
     Advanced motor insulation and nozzle materials were provided
by the following companies for the test: Aerojet Corporation;
Thiokol Corporation; Chemical Systems Division of United
Technology Corporation in San Jose, Calif., and Hercules
Corporation.  Additionally, Thiokol Corporation provided an
experimental insulation material.  Also, an experimental
thermocouple probe, for internal insulation measurements, provided
by Wyle Laboratories, was tested.
     The motor, named the Modified NASA Motor, sits in a test
stand in the Center's East Test Area.  The test motor is 48 inches
in diameter and will be loaded with two propellant cartridges
weighing a total of approximately 11,500 pounds.
     The Solid Propulsion Integrity Program originated from joint
NASA-Department of Defense-industry studies in 1984 which
identified critical shortfalls in the U. S. engineering technology
base for solid-fueled rocket motors.
     The objective of the program is to provide NASA engineers
with the techniques, engineering tools and computer programs to be
able to better design, build and verify solid rocket motors.