139. Memorandum From the Director of the Office of Science and Technology (Press) to President Carter1
SUBJECT
- M–X Missile and Basing Option
As you recall you directed me to convene a panel to review various alternatives for the M–X missile size and basing mode. Although much of their effort focused on multiple protective shelter (MPS) and airmobile ICBM systems, they also briefly considered the recently proposed trench and included some general comments on this system in an addendum to their report (Tab A).2 Following is a brief summary of the panel’s conclusions:
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- Although technically feasible and more effective than other alternatives in preserving the current attributes of our Minuteman [Page 632] force, MPS still has serious shortcomings including verification, break-out and security problems.
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- The trench system could in principle resolve the MPS verification problems but seems to involve an inherent conflict between verification and security. The environmental and security problems could be minimized if the trench were closed most of the time, as DOD is proposing, but this would lead to verification concerns about possible clandestine activities, such as digging side tunnels to store excess missiles.
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- The Panel saw considerable merit in a system which would involve placing some new missiles in current Minuteman silos and some in airplanes. They felt that such a system would have some important advantages due to synergistic cross-force effects. For example, a simultaneous Soviet launch of ICBMs against our silos and SLBMs against our airbased missiles would permit the silo based force to be launched on confirmation of actual nuclear detonation instead of on warning as at present.
Based on the panel’s findings and my own review of this issue, I believe that a mixed silo and air basing approach which includes a new aircraft that would also be used for cruise missile carriage and the TRIDENT II SLBM is the best approach from the standpoint of military and cost effectiveness. The DOD analysis indicates that for comparable expenditures this system would have significantly more warheads and surviving EMT than either the MPS or trench. For political reasons, however, I think that it would be important to use a “mostly common” missile in the silo and airbased forces rather than TRIDENT II. This missile could carry 10 MK–12A RVs, the maximum we are allowed under SALT, and its increased firepower would further enhance the military effectiveness of this option. Since it would have a third stage and guidance system that would not be compatible with SLBM use, it would help offset the Chiefs’ concern that if TRIDENT II is picked, the silo and airbased ICBMs would be dropped entirely at a later point. The mostly common missile could cost an additional 2–3 billion dollars, but this could be offset if necessary by reductions in missile or aircraft procurement.
I believe that this option would also be the most compatible with your arms control objectives. All of its components would be readily verifiable and in view of its tremendous military effectiveness and the fact that many procurement decisions would not actually be made for several years, this option would give us significantly greater negotiating leverage with the Soviets.
In spite of its inherent advantages, however, there may be overriding political objections to this approach. It is not as effective as the MPS or trench in preserving Minuteman’s attributes, and the mostly common missile would not be as large as the 190,000 lb one we are permitted to build under SALT. (It would weigh 170,000 lbs for silo launch and 150,000 lbs for air launch.) For these reasons it is unlikely [Page 633] this option would be supported by the Chiefs. It could be criticized as an abandonment of the triad and could considerably complicate prospects for SALT ratification. Consequently, you may want to proceed instead with some variant of the trench system.
The current approach of having a heavy concrete and ground covering over the entire trench which would only be removed once a year and even then with considerable difficulty would involve verification problems approaching those involved with the MPS. The Soviets have objected repeatedly to our use of temporary shelters over Minuteman silos and could be expected to object even more strenuously to a system that was covered most of the time. It is possible that a different concept, such as placing the tracks and shelters completely on the surface with no covering between shelters, could overcome this verification problem and possibly be acceptable from an environmental and security standpoint. Given the present uncertainties in the trench, however, I recommend that you offer only tentative endorsement of this option pending a fullscale definition study this summer.
There would be considerable objection to yet another delay on the basing mode but this timetable would permit you to reach a final decision by October 1, the M–X reporting date set by the Senate in its review of the FY 80 budget, and prior to the vote on SALT ratification. To minimize objections, however, it would be essential for you to decide now on the size of the M–X missile and to authorize its fullscale development. I recommend you select the mostly common rather than 190,000 lb missile to preserve the flexibility for aircraft basing in the event that the trench problems can not be overcome and to permit eventual use of the first two stages for the TRIDENT II SLBM.