Time to Revive Debate About Space-Based Missile Defense
Current intercontinental ballistic missile (ICBM) defenses do not have the necessary ability to engage the most sophisticated configurations that have been and can be deployed by the Russians and to a lesser extent by the Chinese.
Specifically, U.S. defenses cannot successfully engage ICBMs containing multiply independent reentry vehicles (MIRVs), extensive sophisticated decoys or maneuvering reentry vehicle capability.
Russian missile forces include several thousand ICBMs, and China has 50 to 75. Both countries are in the process of modernizing their forces, and, ominously, by 2020 many of the systems are expected to carry nuclear-tipped MIRVs and sophisticated decoys.
The Russians also have hundreds of submarine-launched ballistic missiles and the Chinese may have dozens.
Although Iranian and North Korean forces are presently not as threatening as Russian and Chinese forces, both may also stockpile sophisticated nuclear ICBMs within a decade. Their missiles currently are non-nuclear and have only intermediate range capability threatening nearby U.S. allies. Other entities or non-state groups could acquire nuclear-tipped ballistic missile weapons as well if unimpeded. Hezbollah in Lebanon, a client of Iran, fits this category.
One configuration to redress this threat is called “brilliant pebbles.” It requires putting 300 to 1,000 spacecraft into low-Earth orbit at an overall cost of roughly $1 billion. That will enable defense in the boost phase to preempt use of MIRVs and other sophisticated countermeasure techniques.
Another defensive technique is the use of standoff remotely piloted aircraft such as the Air Force’s MQ-9 Reaper. They could fire air-to-air missiles at ICBMs that are still in the boost phase. The initial procurement costs would be at least 17 times that of brilliant pebbles, but it would not require placing objects into space and the drones would be recoverable.
A third technique could employ high-energy solid-state lasers deployed in large numbers and placed in low-Earth orbit. This would cost at least 100 times more than brilliant pebbles.
Both the brilliant pebbles and RPV approaches warrant further research and development.
A raging political controversy began in 1972 when the Anti-Ballistic Missile Treaty was adopted by the Nixon administration. The underlying rationale for the treaty was two-fold. First, the ability to achieve reliable defense against sophisticated attacks — MIRVs plus decoys — was considered either excessively expensive or impossible. The second was that the mutually assured destruction policy provided a stable alternative for survivability.
The ABM Treaty prohibited the deployment of new defenses by both the United States and the Soviet Union. It was not challenged for more than a decade.
The June 2002 annulment of the treaty by the George W. Bush administration paved the way for space-based missile defense. Neither the Bush nor the Obama administrations have revived the brilliant pebbles program.
Significantly, nothing in the current land- and sea-based program has global reach and nothing has the range for reliable boost-phase engagement.
Experts contend that space-based missile defense has the potential for reliable boost-phase engagements at the least cost. The savings are significant, a factor of at least 17 compared to the Reaper approach, and a factor of more than 100 compared to the solid-state laser concept.
The main drawback of the space option is the large number of objects placed permanently into low-Earth orbit. That disadvantage is also suffered by the laser defense, but not by the remotely piloted aircraft defense.
Whether or not a large number of objects should be placed into low-Earth orbit is a political judgment that must be balanced against cost considerations and/or the drawback of only partially negating the ICBM threat.
Both the Reagan and George H.W. Bush administrations favored the use of space for missile defense. The Clinton administration canceled all space-based defensive programs. The George W. Bush administration then canceled the ABM Treaty, but did nothing to revive space-based defensive weaponry. The Obama administration instituted an expanded sea-based defense but did not revive the space-based system to engage in the boost phase.
Apparently, the need to provide reliable boost-phase defense against a sophisticated nuclear-armed enemy did not persuade either President Bush or Obama. Since ICBM and submarine-launched ballistic missiles with sophisticated capabilities appear inevitable in coming decades, boost-phase missile defense research should be revived.
Marvin Schaffer is a member of the adjunct research staff at RAND Corp.