The Minuteman National Missile Defense Option

Russia, too, has good reason for being concerned about such an attack against its homeland, because most potential rogue states are located on or near its borders.

Some components of a system that might provide limited defense against a ballistic missile attack have already been developed, and work is proceeding on developing the remaining components. A national missile defense system that uses a modified Minuteman missile as its interceptor could be deployed sooner than any other currently proposed option, should the need arise.

In March 1996, the U.S. Air Force asked RAND's Project AIR FORCE to evaluate the performance capabilities, cost, and arms control treaty implications of completing the development and deployment of the Minuteman option.

System Performance

This NMD option, which includes 20 Minuteman interceptors, is designed to defend all 50 states against an attack of up to four missiles, each armed with a single nuclear warhead.

System performance is governed by the ability to detect, track, discriminate, intercept, and destroy the threat missile. From the specifications of the components of the NMD option (which were an input to the RAND analysis) and a performance analysis, RAND concluded that the system appears capable of engaging four rogue-nation reentry vehicles (RVs) and destroying them with high probability if all of the individual subsystems perform as advertised. The RAND analysis focused on the ability of the Minuteman option to (1) intercept the threat missiles, (2) discriminate between the RVs and other objects, and (3) home on and kill the RV. The modified Minuteman missile has sufficient kinematic performance to fly out from Grand Forks and intercept the threat missiles before they reenter the atmosphere. There also appears to be sufficient time for the X-band radars to discriminate the RVs from simple penetration aids and debris if the discrimination algorithms prove to be effective enough.

Up to now, successful demonstrations of realistic hit-to-kill vehicles have proved elusive. The Minuteman KKV appears to be designed with adequate performance to home on and kill RVs of a certain size and temperature, but available information about the KKV's specifications is not sufficiently detailed to conclude that it has adequate performance against all rogue-nation RVs. Moreover, KKV performance remains a major uncertainty for any antiballistic missile system.

In further analyses, RAND found that the Minuteman system has additional capabilities. The rogue-nation threat assumes that the threat missile has a minimum-energy trajectory and that the RV is spin stabilized. It appears that the Minuteman NMD option also provides some defense against moderately depressed reentry angles (which compresses the engagement timeline) and tumbling RVs (which lengthens the discrimination time needed).

The research team recommended two improvements to the system:

• Add an electronic scanning capability to the X-band radars located on the East and West coasts.

• Consider a supplement to the defense coverage of Hawaii (and perhaps Alaska) with locally based theater missile defense systems or Minuteman NMD interceptors based at Vandenberg Air Force Base (both of which are in conflict with the 1972 "Treaty Between the United States of America and the Union of the Soviet Socialist Republics on the Limitation of Anti-Ballistic Missile Systems," i.e., the ABM Treaty).

Development and Deployment Costs

RAND's cost analyses focused on two issues: (1) Are current estimates of the costs complete (i.e., are the overall program costs structured correctly, and is the full spectrum of development and production phase activities required for an initial NMD capability accounted for)? (2) After adjustment for completeness, is the estimate reasonable (i.e., does it take into account the potential for cost growth in various Minuteman NMD components, as well as programmatic changes and slippage in schedules)?

Initial Air Force estimates showed a total cost of $2.4 billion. RAND's adjustments for completeness suggest that an additional $0.5 billion will be needed, primarily for overall system integration. RAND's analysis of the reasonableness of the adjusted $2.9 billion suggests that another $0.4 billion will be needed for a number of reasons (e.g., the added technical complexity and schedule risk of developing the interceptor modules, as well as the added complexity of developing new interceptor software for target discrimination, data fusion, and aimpoint control functions), bringing the cost to $3.3 billion.

Because many of the components of the Minuteman NMD option are already in the field, the proposed acquisition program has not included the more developmental phases common in entirely new programs (e.g., concept exploration, program definition, and risk reduction). However, the difficulty of the NMD mission and the stringent criterion for mission success suggest that it is important that these activities be included to avoid excessive development risks. These activities range from documenting and approving the system's operational concept, firing doctrines, and threat scenarios to the further development of vehicle discrimination capability, sensor fusion options, and interceptor endgame effectiveness. These additions might result in up to $0.6 billion in additional costs, thus bringing the total cost to the $3.3 to $3.9 billion noted above.[1]

Arms Control Treaty Implications

With regard to territorial defense, Article I of the ABM treaty is germane. However, there is a view that Article I does not impose an independent obligation on the parties to the treaty. Another view is that, while Article I may impose an independent obligation, there are differences about what the word "defend" in Article I means. Does it prohibit a territorial defense, no matter how thin, or does it prohibit a territorial defense only when it is so thick that it could destabilize the strategic nuclear balance between the parties to the treaty? How these questions are answered affects not only the Minuteman NMD options but all candidate NMD options.

The second principal arms control issue involves the siting of the X-band radars. X-band radars located outside of the Grand Forks site could be treaty compliant if they were adjuncts or early warning radars. Adjuncts are not mentioned in the ABM Treaty, but as negotiations evolved, both sides agreed that devices that improved the performance of an ABM system but were not critical to its operation would be allowed as adjuncts. However, the X-band radars are essential to the Minuteman NMD option's ability to provide full territorial defense, so the adjunct argument may not be persuasive. The United States has said in a compliance report on Soviet early warning radars that it would not consider the handover of precise tracking data to be prohibited by the ABM Treaty. However, at sites where early warning radars already exist, the case will be difficult to make that the X-band radars serve primarily a legitimate early warning function, since what they provide is precision tracking and discrimination capability. An additional issue is that the X-band radars located outside of the Grand Forks site probably need to be distinguishable from the X-band radar located at the site. To satisfy that need and to give them a limited early warning capability, we suggest adding a limited-field-of-view electronic scanning feature to X-band radars located on the West and East coasts.

The ABM Treaty was negotiated over 20 years ago. Since then, the relationship between nation states has changed dramatically, and the potential for minor players to inflict severe damage upon their more powerful and more rational neighbors has increased.

That suggests that it may well be time for the United States and Russia to reinterpret or renegotiate the conditions of the ABM Treaty in such a way as to provide better protection for both against rogue states.

Threat Missile Trajectories

RB-47 (1997)