Sensitivity Analysis

Sensitivity Analysis

From: Jane Smith

To: Senior Official

Subject: Sensitivity Analysis of National Missile Defense (NMD) Options


Issue:  Plans and programs for NMD

Sensitivity to Alternative SSPKs.  Experts differ on a realistic assessment of average single shot probability kills (SSPKs).  Estimates range from .25 to .75, with .5 used as a midrange approximation.  Given the key assumptions of the proposed force, anywhere from 0.0003 to 26 Intercontinental Ballistic Missiles (ICBMs) can be expected to reach their targets.  A .5 SSPK can be expected to stop all but two ICBMs.  The increase in accuracy from .25 to .5 saves 24 additional cities, whereas an increase from .5 to .75 only saves an additional two.  There is a greater sensitivity in the lower range between .25 and .5, which decreases the closer SSPK comes to 1.

Impact of Larger NMD Strategic Reserves.  In the event that a second round of ICBM’s targeted the U.S., a reserve of 25 Midcourse Intercepts (MCIs) would forfeit 12 cities, and 50 MCI’s would only save approximately 6 more.  An additional 125 MCI’s would be required to provide near complete protection.  The cost of the additional reserve would run $9.2 billion or $37.1 billion, for an increase of 25 and 100 reserve MCI’s respectively.  A greater MCI reserve would provide flexibility in the case of a second attack, and continue to protect the nation while replacement interceptors could be produced.  However, a robust MCI reserve would cost almost half again as much as the original plan.

Implications for Current Deployment Plan : Larger Deployment. 

Option A/Two targets hit in first attack – twelve targets hit in second attack – Cost $82.5 billion – Program duration seven-years: Maintaining the current DOD plan provides defense against a limited attack while minimizing loss of life.  It does not offer much flexibility in case of a second attack.

Option B/Two targets hit in first attack -  six targets hit in the second attack – Cost $91.7 billion – Program duration seven-years eleven months:  Increasing the MCI reserve by 25 decreases targets hit in the second attack by 50%, while only adding marginal cost and time expenditures.

Option C/Two targets hit in first attack – less than one target hit in second attack – Cost $119.6 billion – Program duration ten years six months:  Increasing the MCI reserve to 125 provides strong coverage with a high price tag.  Acquiring the necessary funds could prove difficult.

All options should be reassessed at marked intervals to review their effectiveness in light of technological advances, costs, and developing political realities.

As with all low-probability, high-risk events, resource allocation for NMD is problematic.  Given the present political situation it may be unlikely that an adversary would launch nuclear missiles at the United States.  The more likely threat will come from terrorists using the transportation system (i.e. container ship, rail, etc.) to smuggle a weapon into the country.  However, this equation may change.  In any case, it could take ten years to develop a credible NMD system.  The current plan may be a necessary step in creating a more advanced defense system for defending against peer competitors in the mid to long-term future. 

The economic cost of a nuclear attack can only be estimated.  One calculation ranges from $150 billion to $3 trillion for lose of life, $500 billion for property damage, and $5 billion weekly for highway and rail disruption.  Therefore, even the damage of two cities carries a starting cost of $1.3 trillion.  This does not address the economic loss from government and economic discontinuity if Washington or New York were hit, the worldwide economic effect, or the numerous secondary disruptions.  The World Bank estimated that 9/11 cost the world economy $80 billion, and sunk 10 million people below the poverty line.  Simply from an economic viewpoint, even a limited successful nuclear attack on the United States would cost substantially more than this proposed NMD plan.

Given the adversarial nature of the budget process, and the complexities in judging the efficacy of various programs, it is extremely hard to evaluate where funds might be better spent.  A prudent mix of diplomacy, arms control initiatives, and military strength would address this threat from many angles.  However, NMD offers an option when all else fails.

Implications for Current Deployment Plan : Additional Research, Development, Testing, and Evaluation (RDT&E).  Adding $2 billion dollars to RDT&E offers a 50% chance of improving SSPK’s in .25 increments.  In the event that SSPK were to improve from .25 to .5, only 28 MCI’s would be needed to provide similar coverage to the original plan, and an improvement from .5 to .75 would drop that requirement to 30 MCI’s.  Assuming reduced production rates of 23.2 units per year, SSPK improvement from .25 to .5 would provide savings of $38 billion at the 3-year mark, and $20 billion at the 5-year mark.  SSPK improvement from .5 to .75 at the 3-year mark would save $41 billion, and at the 5-year mark $23 billion.  The program schedule could be reduced anywhere from one to three years. 

While a Boost Phase Intercept (BPI) seems to be effective, it must be utilized in the first four minutes after launch, and is region specific.  MCI provides 25 minutes to act, but its effectiveness is a source of contention.  Critics claim that MCI is highly vulnerable to countermeasures such as anti-simulation balloon decoys or cooled shrouds, technologies easily attained by any adversary who operates warheads in the first place.  Given these issues, and the possibility of improvement in a variety of systems, such as space-based lasers, it is advisable to add $2 billion per year to annual RDT&E.  While there are never any guarantees that research will provide the needed improvements, the nuclear threat suggests NMD is at least one avenue that should be explored to confront proliferation.