oversight

Strategic Forces: Minuteman Weapon System Status and Current Issues

Published by the Government Accountability Office on 1990-09-28.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                          STRATEGIC FORCES
                          Minuteman Weapon
                          System Status and
                          Current Issues




                                                                          142533




                      IUFSTRICTED---Not     to be rel&&&&&&         the
                      General Accounting Ofllce unless specifically
                      approved by the Office of Congressional
                      Relations.


(;hO/NSIAI)-!)O-242
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                   United States
GAO                General Accounting Office
                   Washington, DC. 20648

                   National Security and
                   International Affairs Division

                   B-239571

                   September 281990

                   The Honorable Les Aspin
                   Chairman, Committee on Armed Services
                   House of Representatives

                   Dear Mr. Chairman:

                   As requested, we evaluated the Air Force’s plans to retain the Min-
                   uteman II and III missile force through fiscal year 2008. Specifically, we
                   identified the costs to sustain the Minuteman force and assessed the
                   impacts of aging on the systems, the programs planned to support life
                   extension, and the capability of the Air Force to assess and demonstrate
                   the operational condition of the missiles. In January and March 1990,
                   we briefed your office on the preliminary results of our review. This
                   report summarizes and updates those briefings.


                   The Intercontinental Ballistic Missile Systems program office estimated
Results in Brief   that, as of May 1989, about $30.4 billion in then-year dollars would be
                   needed to extend the life of the Minuteman force through fiscal year
                   2008. However, in light of the Secretary of Defense’s recent announce-
                   ment to retire about half of the force (450 Minuteman II missiles) by
                   1998 if a Strategic Arms Reduction Talks agreement is reached, the esti-
                   mate will decrease by an amount not yet determined by the program
                   office.

                   The program office states that to extend the life of the Minuteman
                   weapon system through fiscal year 2008, the force must be maintained
                   in a launch ready state with a high probability of successful launch,
                   flight, and target destruction, The Minuteman III missiles are currently
                   being maintained in accordance with this planning criterion, but the
                   Minuteman II missiles are not.

                   Confidence that the Minuteman II can meet this criterion is questionable
                   because of (1) limited flight testing, due to a shortage of test missiles
                   and (2) reduced reliability, caused by age-related deterioration of gui-
                   dance computers and Stage 3 propulsion motors. Additionally, because
                   of the limited number of flight tests, the Department of Energy cannot
                   certify the reliability of the Minuteman II warhead.

                   Minuteman III missiles, which are not as old as the Minuteman II mis-
                   siles, have not yet experienced the operational performance problems


                   Page 1                               GAO/NSLAD-90-242   Minuteman   Weapon System
             facing Minuteman II missiles. However, on the basis of the Air Force’s
             and the Department of Energy’s current testing schedules, the Air Force
             will not have spare components for flight testing to support reliability
             assessments of that system’s nuclear warhead after 1999.

             Under current Air Force plans, confidence in Minuteman II missile per-
             formance cannot be restored and sustained. Confidence in Minuteman III
             warhead performance will begin degrading after 1999.


             The current Minuteman force structure consists of 450 single-warhead
Background   Minuteman II missiles (fielded in 1965) and 500 three-warhead Min-
             uteman III missiles (fielded in 1970) deployed in underground silos at
             various Air Force bases in the continental United States. (See app. I for
             a detailed description of the Minuteman weapon system.) The Min-
             uteman force has far exceeded its initial design life goal of 10 years.

             Air Force Headquarters has directed that the Minuteman force be sus-
             tained beyond the year 2000. According to Air Force Headquarters offi-
             cials, this direction was given because progress of intercontinental
             ballistic missile modernization was slower than planned, which placed
             increased and extended reliance on the Minuteman force as a nuclear
             deterrent.

             The United States and the Soviet Union have agreed to expedite the
             Strategic Arms Reduction Talks negotiations with the objective of
             resolving all substantive issues. These negotiations will substantially
             reduce both countries’ strategic offensive forces and place ceilings on
             the number of strategic offensive warheads and delivery systems. The
             United States and the Soviet Union have proposed that the reductions
             be carried out in a phased manner, achieving equal ceilings by agreed
             dates.

             In January 1990, the Secretary of Defense announced that if a Strategic
             Arms Reduction Talks agreement were reached, the Minuteman II force
             would be retired beginning in 1992. About 64 Minuteman II missiles
             would be retired annually over a 7-year period. At that rate, all 450 Min-
             uteman II missiles would be retired by about 1998. More recently, in
             authorizing appropriations for the Department of Defense for fiscal year
             1991, the Senate Committee on Armed Services identified the Min-
             uteman system as one that should be considered for early retirement.




             Page 2                               GAO/NSIAD9@242   Minuteman   Weapon System
                                         B-239571




                                         The program office states that the Minuteman force must be maintained
Minuteman Life                           in a launch ready state with a high probability of successful launch,
Extension Cost                           flight, and target destruction, It has developed a long range plan that
Estimate                                 identifies the life extension programs (modifications, replacements,
                                         refurbishment, etc.) and associated costs to sustain the Minuteman force
                                         through fiscal year 2008.

                                         The most recent program office estimate (May 1989) shows that about
                                         $30.4 billion in then-year dollars will be needed to maintain an effective
                                         Minuteman force from fiscal years 1984 through 2008 (see table 1).

Table 1: Cost Estimate for Maintaining
the Mlnuteman Force                      Dollars in billions
                                                                                                             Average annual
                                                                                            Total cost                 cost
                                         Operations and support                                  $19.0                 $0.8
                                         Life extension woarams                                   10.8                   0.4
                                         Capability enhancements                                   0.8                  0.02
                                                                                                 $30.4                $1.22


                                         Program officials stated that the estimate represents a planning esti-
                                         mate and should not be used to support programmatic decisions or budg-
                                         etary allocations. They added that the estimate, however, does provide a
                                         reasonable representation of past and future costs associated with daily
                                         operations and extending the useful life of the Minuteman force through
                                         fiscal year 2008.


                                         Operational flight testing provides the only complete, end-to-end check
Flight Testing Issues                    of weapon system operation from launch command initiation to reentry
                                         vehicle impact. Operational test flights also provide the accuracy and
                                         reliability data used to develop planning factors for the nuclear war
                                         plan.

                                         The Joint Chiefs of Staff has established guidelines that specify min-
                                         imum statistical confidence levels required for weapon system relia-
                                         bility. The Strategic Air Command has determined that seven
                                         Minuteman II and seven Minuteman III flights per year are needed to
                                         comply with Joint Chiefs of Staff and Command guidance for main-
                                         taining minimum confidence in weapon system performance. Also, as
                                         part of the Strategic Air Command’s annual flight test program, two
                                         Minuteman II and six Minuteman III test flight missiles must be



                                         Page 3                               GAO/NSIAD-90-242   Minuteman    Weapon System
                      E239671




                      equipped with Department of Energy configured test reentry vehicles to
                      demonstrate that the warhead will function as intended.


Minuteman II Flight   A shortage of missiles and missile components is curtailing operational
Testing               flight testing of the Minuteman II system, and on the basis of current
                      plans, these will continue to curtail this testing. During the 198Os, only
                      11 of the 70 needed Minuteman II flight tests were conducted (see app.
                      III). Flight testing was suspended in 1987 because of the limited availa-
                      bility of flight test missiles and the planned replacement of guidance
                      system computers and Stage 3 propulsion motors.

                      Flight testing was scheduled to resume in fiscal year 1993 when replace-
                      ment guidance system computers and Stage 3 propulsion motors were to
                      become available. However, those replacements have been canceled in
                      anticipation of Minuteman II retirement. Because of the limited test pro-
                      gram, the confidence in the operational effectiveness of the Minuteman
                      II system is questionable, and Department of Energy officials at the
                      Albuquerque Operations Office advised us that it cannot certify that the
                      Minuteman II warhead will function as intended,

                      The Strategic Air Command is assessing the need to resume Minuteman
                      II test flights. However, only 22 Minuteman II missiles remain for flight
                      testing. If flight testing is resumed, according to the program office, all
                      of these missiles will need to be flown during a 3-year period to reestab-
                      lish a performance baseline. Consequently, missiles will not be available
                      for the flight testing needed to maintain continued confidence in system
                      performance through fiscal year 2008.

                      The Air Force is considering plans to alleviate the flight test asset
                      shortage. One plan is to procure additional missiles, but, according to
                      program officials, the probability of procuring additional flight test mis-
                      siles is very low because of their high cost. Another plan being consid-
                      ered is the reduction of the operational force to make Minuteman II
                      missiles available for flight testing. However, the use of operational mis-
                      siles would require the conversion of an operational reentry vehicle
                      equipped with its warhead into a nonnuclear test reentry vehicle
                      without a warhead. According to Air Force officials, this conversion can
                      be done. However, Department of Energy officials at the Albuquerque
                      Operations Office stated that a feasibility study of such a conversion
                      has not been done and that such a study has not been directed.




                      Page 4                               GAO/NSIAD-99-242   Minuteman   Weapon System
                       Jib299571




Minuteman III Flight   During the 1980s the needed seven Minuteman III flight tests per year
Testing                were conducted (see app. IV). These flights have shown that the Min-
                       uteman III missile is meeting the specification requirements for accuracy
                       and reliability. The Air Force had plans to continue flight testing Min-
                       uteman 111sat a rate of seven per year until about calendar year 2004.
                       To support these flights, the Air Force is acquiring additional MK 12 and
                       MK 12A reentry vehicle components. After 2004, however, nearly 4
                       years before the end of the currently planned life of the system, the
                       existing inventory of flight test missiles would have been depleted.

                       On August 1, 1990, Strategic Air Command officials advised us that it
                       has decided, beginning in fiscal year 1990, to reduce the number of
                       annual Minuteman III flights from seven to four due to fiscal con-
                       straints. At a rate of four flight tests per year, there will be sufficient
                       missiles to allow flight testing through fiscal year 2008. The Strategic
                       Air Command believes it can reasonably monitor the performance of the
                       Minuteman III missiles with only four flight tests per year, considering
                       the proven reliability of the system and the existing large base of Min-
                       uteman III performance data. Since this decision was made near the con-
                       clusion of our review, we have not made a full assessment of the
                       impacts of the decision on the ability to confidently estimate Minuteman
                       III reliability and accuracy.

                       Concerning the Minuteman III warhead, Department of Energy officials
                       at the Albuquerque Operations Office stated that, as part of the Stra-
                       tegic Air Command’s flight test program, flight testing of three MK 12
                       and three MK 12A reentry vehicles equipped with nonnuclear warhead
                       electrical systems is being accomplished and is demonstrating that the
                       warhead will function as intended. Additional MK 12A nonnuclear war-
                       head electrical systems will be needed, however, to allow flight testing
                       after 1999.

                       Department of Energy officials at the Albuquerque Operations Office
                       stated that it is unlikely that a manufacturing capability for the MK 12A
                       warhead electrical systems still exists. If this capability does not exist,
                       then other actions will need to be taken to ensure extending flight
                       testing through fiscal year 2008. Department of Energy officials stated
                       one such action would be developing and acquiring a new warhead elec-
                       trical system. These same officials stated that another action could be
                       the reduction of the operational Minuteman III force as nonnuclear elec-
                       trical systems from operational missiles are expended during flight
                       testing and not replaced.



                       Page 5                               GAO/NSIAIMKL242   Minuteman   Weapon System
                     B-289571




                     The Air Force has been aware of age-related deterioration of Minuteman
Reliability Issues   weapon system components since the mid-1970s and it has implemented
                     several programs to correct age-related deterioration of Minuteman II
                     and III missile components in order to maintain weapon system relia-
                     bility.’ (See app. II.)

                     Currently, the program office is reporting that the reliability of the Min-
                     uteman III missiles is at an acceptable level, but the reliability of the
                     Minuteman II missiles is substantially reduced because of age-related
                     deterioration of guidance system computers and Stage 3 propulsion
                     motors. The reliability of the Minuteman II force will remain a problem
                     because the Air Force’s plans to replace the Stage 3 motors were can-
                     celed in anticipation of Minuteman II retirement. Also, the Air Force had
                     planned to implement a guidance computer replacement program in
                     fiscal year 1990 at an estimated cost of $696 million in then-year
                     dollars. However, the fiscal year 1990 appropriation of $76 million was
                     transferred for other uses, and the $110 million requested for fiscal year
                     1991 was deleted. According to program officials, the replacement of the
                     guidance computer is the key to improving Minuteman II reliability.


                     The Minuteman missiles have served as a nuclear deterrent for a longer
Conclusions          period of time than was contemplated when the first missiles were
                     deployed about 25 years ago. Over the extended lives of the systems,
                     questions have arisen about their continued reliability and operational
                     effectiveness, particularly the Minuteman II system. Confidence in Min-
                     uteman II operational performance is reduced because of limited flight
                     testing during the 1980s and deterioration of critical missile compo-
                     nents. The Air Force does not currently have a plan that would provide
                     the test assets needed to restore and sustain confidence in the Min-
                     uteman II system’s operational performance.

                     These factors, when considered in conjunction with the cost to operate
                     and support the system, suggest that the Minuteman II system could be
                     retired earlier than 1998 as presently contemplated under an assump-
                     tion of a Strategic Arms Reduction Talks agreement. An alternative
                     would be to reinstate the Air Force’s plans to replace deteriorated mis-
                     sile components and acquire the assets needed to resume flight testing at
                     rates necessary to restore and sustain confidence in the system’s per-
                     formance for the remainder of its operational life through fiscal year
                     2008.

                     ‘Reliability is the probability that a missile will deliver and detonate its warhead in the target area.



                     Page 6                                              GAO/N&ID-90-242        Minuteman     Weapon System
                  B-239571




                  Minuteman III missiles are to remain in the force until fiscal year 2008.
                  However, based on current test schedules, by about 1999, components to
                  test the missile’s warhead will be depleted. Thus, confidence in the oper-
                  ational effectiveness of the Minuteman III warhead performance will
                  become questionable after 1999.


                  In view of (1) the Department’s decision not to correct the deteriorating
Recommendations   condition of the missile and (2) the several hundred million dollars in
                  costs to operate and support the system, we recommend that the Secre-
                  tary of Defense direct the retirement of the Minuteman II weapon
                  system at a rate that would retire the system earlier than the projected
                  date of 1998, consistent with any Strategic Arms Reduction Talks agree-
                  ments that are concluded.

                  We also recommend that the Secretary of Energy, in conjunction with
                  the Secretary of Defense, develop a plan to ensure the availability of
                  Minuteman III MK 12A warhead components for flight testing through
                  fiscal year 2008.


                  We concentrated on life extension issues related to the Minuteman II and
Scopeand          III missiles only, as opposed to all elements of the weapon system such
Methodology       as operational ground equipment, because the impact of aging on system
                  reliability was primarily missile related. However, we did identify and
                  analyze life extension costs related to the entire weapon system.

                  We interviewed appropriate officials and examined pertinent documents
                  at the Ogden Air Logistics Center, Hill Air Force Base, Utah; the Stra-
                  tegic Air Command Headquarters, Offutt Air Force Base, Nebraska; the
                  San Antonio Air Logistics Center, Kelly Air Force Base, Texas; the Office
                  of the Secretary of Defense and Air Force Headquarters, Pentagon; and
                  the Albuquerque Operations Office, Department of Energy, Kirkland Air
                  Force Base, New Mexico.

                  As agreed with your office, we did not obtain agency comments on this
                  report. However, we discussed a draft of this report with officials from
                  the Office of the Secretary of Defense, Air Force Headquarters, Ogden
                  Air Logistics Center, Strategic Air Command, and the Department of
                  Energy’s Albuquerque Operations Office and incorporated their com-
                  ments as appropriate.




                  Page 7                              GAO/NSIAD-99-242   Minuteman   Weapon System
                                                                        I




B-2.99671




We performed our review from July 1989 through June 1990 in accor-
dance with generally accepted government auditing standards.


We plan no further distribution of this report until 30 days from its
issue date unless you announce its contents earlier. At that time we will
send copies to the Secretaries of Defense, the Air Force, and Energy; the
Director, Office of Management and Budget; and appropriate congres-
sional committees. Copies will also be made available to others on
request.

Please contact me at (202) 275-4268 if you or your staff have any ques-
tions concerning this report. Other major contributors to this report are
listed in appendix V.

Sincerely yours,




LlftiZf+Y .
Director
Air Force Issues




Page 8                               GAO/NSIAE@@242   Minuteman   Weapon System
Page 9   GAO/NSLAD-BO-242   Minuteman   Weapon System
Contints


Letter
Appendix I
Minuteman Weapon        Force Structure Description
System Description
Appendix II                                                                                          15
Programs to Replace     Propulsion Motor Programs
                        Guidance System Programs
                                                                                                     15
                                                                                                     17
Deteriorating Missile
Components
Appendix III                                                                                         18
Number of Minuteman
II Test Flights
Conducted During the
1980s
Appendix IV
Number of Minuteman
III Test Flights
Conducted During the
1980s
Appendix V
Major Contributors to
This Report
Tables                  Table 1: Cost Estimate for Maintaining the Minuteman                          3
                            Force
                        Table II. 1: Location of Minuteman Force                                     12




                        Page 10                            GAO/NSIAD-90-242   Minuteman   Weapon System
Page 11   GAO/NSIAD-90-242   Minuteman   Weapon System
Appendix I

Minuteman Weapon System Description


                                         The U.S strategic nuclear forces consist of submarine-launched ballistic
                                         missiles, manned bombers, and land-based intercontinental ballistic mis-
                                         siles. Since the 196Os, this triad of nuclear forces has contributed to the
                                         primary objective of the nation’s strategic forces-deterrence      of nuclear
                                         war. The Minuteman weapon system is part of the US. land-based inter-
                                         continental ballistic missile force, which is comprised of 1,000 silo-based
                                         missiles-60 Peacekeeper and 950 Minuteman missiles.


                                         The current Minuteman force consists of 460 Minuteman II missiles and
Force Structure                          500 Minuteman III missiles. Minuteman II missiles were first deployed in
Description                              1966, followed by the first deployment of Minuteman III missiles in
                                         1970. * The current Minuteman force is deployed in underground silos
                                         located at various Air Force bases, as shown in table II. 1.

Table 11.1:Location of Minuteman Force
                                                                                                                    Minuteman
                                         Air Force Base                 State                                  II                          III
                                         Malmstrom                      Montana                             150                            50
                                         Ellsworth                      South Dakota                        150                             0
                                         Minot                          North Dakota                          0                           150
                                         Whiteman                       Missouri                            150                             0
                                         F.E. Warren                    Wyoming                                0                          150
                                         Grand Forks                    North Dakota                           0                      150
                                         Total force size                                                   450                       500


                                         The Minuteman weapon system is comprised of two primary elements:
                                         the missile and the operational ground equipment that are required to
                                         support the deployed force of Minuteman missiles.


Minuteman II Missile                     The Minuteman II missile is 57.6 feet long and 5.6 feet in diameter and
                                         weighs 73,000 pounds. It is capable of speeds in excess of 15,000 miles
                                         per hour, and it has a range of over 6,300 nautical miles. The missile
                                         consists of a three-stage propulsion system, a missile guidance and con-
                                         trol system, and a reentry vehicle.

                                         The propulsion system is made up of three solid propellant rocket
                                         motors, providing enough thrust to achieve intercontinental ranges. The
                                         missile guidance system is an inertial guidance system that directs the

                                         ‘The original Minuteman III force of 660 missiles was reduced to 600 by 1988 when 60 Minuteman
                                         111swere replaced with 60 Peacekeeper missiles in modified Minuteman silos.



                                         Page 12                                         GAO/NSLADgo-242      Minuteman   Weapon System
                        Appe-    1
                        lKlm&man   Weapon System Description




                        flight of the missile to its programmed target,2 and the guidance system
                        operates continuously when the missile is on alert status enabling mis-
                        sile launch in less than 1 minute. The reentry vehicle is a Mark 1lC and
                        is equipped with the highest yield warhead in the US. land-based inter-
                        continental ballistic missile arsenal.


Minuteman III Missile   The Minuteman III missile is 59.9 feet long and 5.5 feet in diameter and
                        weighs 75,000 pounds. The missile consists of a three-stage propulsion
                        system and a post-boost vehicle comprised of a propulsion system rocket
                        engine, a missile guidance system, and a reentry system.

                        The Minuteman III is the latest generation of Minuteman missiles with
                        improved performance characteristics. The Minuteman III uses the same
                        solid propellant rocket motors as the Minuteman II missile for its first
                        and second stages, but the performance of the Minuteman III’s Stage 3
                        motor has been improved, and a post-boost propulsion system has been
                        added to increase the missile’s range and capacity to deliver multiple
                        warheads. The Minuteman III’s guidance system has been improved. For
                        example, improved electronics within the guidance system have
                        increased the missile’s accuracy and reduced its vulnerability to a
                        nuclear environment. Also, the Minuteman III can carry up to three
                        reentry vehicles/warheads that can be independently targeted, pro-
                        viding greater targeting flexibility, whereas the Minuteman II only car-
                        ries one reentry vehicle/warhead. Furthermore, the Minuteman 111sare
                        equipped with two different reentry vehicles-200 with the MK 12
                        reentry vehicle and 300 with the MK 12A reentry vehicle, which has a
                        higher yield warhead than the MK 12.


Operational Ground      Each Minuteman missile is deployed upright in unmanned silos that
Equipment               have been hardened against blast, shock, radiation, and electromagnetic
                        pulse. These silos are underground about 90 feet deep and 12 feet in
                        diameter.

                        The silo-based missiles are controlled by underground launch control
                        centers located at remote sites away from the silos. The launch control
                        centers are blast resistant, shock mounted capsules manned by two mis-
                        sile combat crew members who continuously monitor the security and
                        condition of 10 missiles and silos by using displays, alarms, and


                        “The guidance system cannot be changed or affected from the ground once a missile is launched.



                        Page 13                                          GAO/NSIMMO-242       Minuteman    Weapon System
Appendix I
Minuteman Weapon System Description




printouts, Each center is equipped with multiple communications sys-
tems to receive commands and transmit launch signals to the remotely
located silos.

The silo-based Minuteman force also is supported by an airborne launch
control center. The airborne launch control center can assume command
and control responsibility for the missile force and perform targeting
and launch operations if ground-based launch control centers are
disabled.




Page 14                               GAO/NSIAD-90-242   Minuteman   Weapon System
Appendix II

Programs to ReplaceDeteriorating
Missile Components

                   The Air Force has been aware of age-related deterioration of the Min-
                   uteman weapon system components since the mid-19709 but did not
                   fully assess the impact of aging on weapon system reliability until Sep-
                   tember 1987. As a result of several flight test failures of Minuteman III
                   missiles during 1987, the Chief of Staff of the Air Force directed that a
                   multicommand reliability assessment of the Minuteman III weapon
                   system be initiated to determine the condition of the weapon system and
                   the specific impacts of age degradation on weapon system reliability.

                   The Minuteman III reliability assessment identified some potential age-
                   related deficiencies with the missile guidance system and Stage 3 pro-
                   pulsion motor but concluded that the impact of these deficiencies on reli-
                   ability was thought to be low. The assessment concluded that these
                   deficiencies had not directly attributed to any flight test failures. The
                   potential deficiencies are being monitored, and the program office is
                   reporting that the reliability of the Minuteman III missiles is at an
                   acceptable level, as evidenced by recent successful flight test results.

                   The Minuteman III assessment resulted in a reliability assessment of the
                   Minuteman II missile. The results of the Minuteman II assessment,
                   issued in March 1988, showed that the missile was exhibiting aging
                   effects, particularly within the guidance system computer and the Stage
                   3 propulsion motor -the two components having the greatest impact on
                   reducing weapon system reliability. Accordingly, the Air Force estab-
                   lished programs to replace these two components, but funding was can-
                   celed in expectation of Minuteman II retirement. Currently, the program
                   office is reporting that the reliability of Minuteman II missiles is sub-
                   stantially reduced.

                   To correct the age-related deterioration, the Air Force has implemented
                   several programs and has plans for several others for both the Min-
                   uteman II and Minuteman III missiles. Some of these programs are dis-
                   cussed below.


                   The Minuteman II and Minuteman III missiles’ Stage 1 motors are virtu-
Propulsion Motor   ally identical. The motors have surpassed their expected lives, and test
Programs           results indicate statistically significant aging trends. However, no opera-
                   tional problems are expected in the near future. If problems arise, the
                   program office will implement a program to refurbish the entire inven-
              1    tory of 1,140 Stage 1 motors, beginning in fiscal year 1993, at an esti-
                   mated cost of $1.6 billion in then-year dollars.



                   Page 16                              GAO/NSIAD-SO-242   Minuteman   Weapon System
Appendix II
Programs to Replace Deteriorating
Missile Components




Assessments performed during the mid-19709 on the Stage 2 motors,
which are virtually identical for the Minuteman II and Minuteman III
missiles, found a gradual deterioration of the liner, and as a result, the
program office established a useful motor life of 17 years. Accordingly,
a program to replace the liner and propellant in all Stage 2 motors began
in February 1979. All Minuteman II motors have been replaced, and
replacement of Minuteman III motors will be completed in fiscal year
1993 before the motors exceed their 17-year useful lives. Another liner
and propellant replacement program is scheduled to begin in fiscal year
1994 at an estimated cost of $581 million in then-year dollars.

The Minuteman III Stage 3 propulsion motor uses the same liner and
propellant used in the Stage 2 propulsion motor. The liner and propel-
lant in the Stage 3 motor were also found to be deteriorating. A program
to replace the liner and propellant began in fiscal year 1983, and it is
scheduled for completion in fiscal year 1993. Another liner and propel-
lant program is planned to begin in fiscal year 1998 at an estimated cost
of $671 million in then-year dollars.

Seven age-related potential failure modes have been identified in the
Minuteman II Stage 3 propulsion motor. However, because of limited
test assets, only one failure mode-premature     thrust termination part
actuation -has been assessed and is known to be reducing weapon
system reliability. The Air Force had planned to implement a program to
replace some older Stage 3 motors with new motors. The older motors
could then be used to assess the reliability impact of the other six poten-
tial failure modes. However, the program was canceled in anticipation of
Minuteman II retirement.

The Air Force is refurbishing the thrust termination ports in all Stage 3
motors. According to a program official, as of December 1989,375 of the
450 deployed Minuteman II missiles had refurbished thrust termination
ports, and the remaining 75 missiles will be refurbished by the end of
fiscal year 1993. In the interim, the force will have Stage 3 motors with
questionable performance. Compounding this condition is that the
expected service life of Stage 3 motors is 162 months, and almost all the
unrefurbished motors are at least 209 months old.




‘Premature thrust termination port actuation is caused by aging and the resulting leakage of O-rings
and seals and degradation of the potting material in the thrust termination ports.



Page 16                                           GAO/NSIAlMO-242      Minuteman    Weapon System
                  Appendix II
                  Program13 to Replace Deteriorating
                  Missile Component8




                  Age degradation of electrical components and faulty technology were
Guidance System   identified in some Minuteman II guidance system components during a
Programs          missile guidance set and flight control degradation assessment study
                  dated August 1984. As a result, in 1985, the Air Force implemented an
                  accuracy, reliability, and supportability improvement program that is
                  scheduled for completion at the end of fiscal year 1992 at an estimated
                  cost of $237 million in then-year dollars. This program upgrades and
                  replaces degraded and faulty electronics with current technology elec-
                  tronics in addition to providing software changes to enhance accuracy.

                  The Minuteman II reliability assessment study also determined that age
                  degradation in the Minuteman II missile guidance computer was occur-
                  ring, and subsequent ground testing showed a substantial reduction in
                  Minuteman II reliability. This degradation is separate and distinct from
                  the electronics degradation being corrected by the accuracy, reliability,
                  and supportability program. The study indicated an increasing failure
                  rate of the guidance computer. Of particular concern was the abnormal
                  number of guidance computers rejected less than 30 days after installa-
                  tion. The Air Force had planned to implement a guidance computer
                  replacement program in fiscal year 1990 at an estimated cost of $696
                  million in then-year dollars. However, the fiscal year 1990 appropriation
                  of $76 million was transferred for other uses, and the $110 million
                  requested for fiscal year 1991 was deleted. According to program offi-
                  cials, the replacement of the guidance computer is the key to improving
                  Minuteman II reliability.

                  Similarly, the Minuteman III reliability assessment study indicated con-
                  cern about age degradation of some missile guidance system compo-
                  nents. Given the similarities with the Minuteman II guidance system, the
                  Minuteman III guidance system is also expected to require upgrades and
                  modifications, and engineering evaluation, test, and analyses are being
                  conducted to assess the need for a complete upgrade. If necessary, a pro-
                  gram designed to upgrade the Minuteman III guidance system could be
                  implemented in the mid- to late-1990s.




                  Page 17                              GAO/NSIAD-SO-242   Minuteman   Weapon System
Appendix III

Number of Minuteman II Test Flights
Conducted During the 1980s

               Calendar year                                   Number of flights               Number successful
               I can5   ““”
                                                                                   1                                  1
               --



               1981                                                                0                                  0
               1982                                                                3                                  2
               1983                                                                2                                  2
               1984                                                                1                                  1
               1985                                                                0                                  0
               1986                                                                0                                  0
               1987                                                                4                                  2
               ------
               1988                                                                0                                  0
               1989                                                                0                                  0
               Total                                                             11                                   8
               Note: According to Strategic Air Command guidelines, 70 test flights were needed during this lo-year
               period.




               Page 18                                            GAO/NSIAlHO-242       Minuteman    Weapon System
      1




Appendix IV

Number of Minuteman III Test Flights
Conducted During the 1980s

                                              Number of flights
                                          Number     Numbe;;itt          Numbg y;it.
               Calendar year   Total   successful
               1980               8              7                 6                    2
               ___-
               1981               8              8                 3                    5
               1982               6              4                 3                    3
               1983               7              5                 3                    4
               1984               7              6                 2                    5
               1985               6              3                 3              3
               1986               7              6                 3                4
               1987               7              4                 4                3
               1988               5              5                 3                2
               1989               7              7                 4                3
               Total             68             55                34               34




               Page 19                   GAO/NSlAD-90-242   Minuteman   Weapon System
Appendix V

Major Contributors to This Report


                        Norman J. Rabkin, Associate Director
National Security and   Steven F. Kuhta, Assistant Director
International Affairs   John J. Klotz, Assignment Manager
Division, Washington,
D.C.
                        James Dinwiddie, Evaluator-in-Charge
Los Angeles Regional    Michael decastro, Evaluator
Office                  Meeta Sharma, Evaluator




(392604)                Page 20                            GAO/NSIAJJ-90-242   Minuteman   Weapon System
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