On Monday we had a physics colloquium by Daniel Kleppner of MIT, on the subject "Can A Boost-Phase Intercept System Assist Missile Defense?". He was summarizing the results of the American Physical Society's Study Group on Boost-Phase Intercept Systems for National Missile Defense. You can find their results here. Let me briefly summarize.
The main approach to missile defense has been to aim for the ICBM in the 20-minute phase where it is at cruising altitude. One of the major difficulties here is that, beyond the difficulty of hitting the missile in the first place, any number of fairly simple countermeasures could make the task far more difficult.
Lately there has been talk of "boost-phase intercept," that is, hitting the ICBM in the phase where a booster rocket is accelerating it. The time scale for this acceleration is four minutes for liquid-fuel rockets and as short as two minutes for solid-fuel ones. This means that one must make a very quick decision after the missile launch to shoot it down. Then one must be able to hit it as it accelerates. The APS study found that this might be possible but will require a very large "kill vehicle," which then requires a very large rocket to launch and accelerate to the speeds that you need. The upshot of this is that it is not feasible to launch very many interceptors, and that one must be very close to the launch site of the ICBM you're targeting to hit it in time. For North Korea this would mean essentially placing the interceptor launch site in their waters; for Iran it would mean placing launch sites in places like Turkmenistan or Afghanistan where one wouldn't be able to rely on agreement from their government. There are numerous difficulties and the APS study determined that this type of missile defense is not feasible. Look over the report, it's interesting.
Another issue is that even if you hit the missile in its boost phase, this will probably not destroy it but simply cause it to fall short of its target. For an Iranian missile this could mean that it would land in western Europe. The chances of such a shot-down missile landing in an area nearly as populated as the one it was aimed for are slim, but this is still something to think about. Also, due to the quick decision required there's some chance you would choose to shoot down something like a satellite launch, which would make people very unhappy with you.
The reason this seems particularly worth pointing out is that, in the first Bush-Kerry debate (near the end), Kerry cited nuclear proliferation as the biggest threat to US national security, and Bush similarly cited "weapons of mass destruction." An excerpt:
Mr. Lehrer Just for this one-minute discussion here, is it - just for whatever seconds it takes: so it's correct to say that if somebody's listening to this, that both of you agree - if you're re-elected, Mr. President, and if you are elected, the single most serious threat you believe - both of you believe is nuclear proliferation.
Mr. Bush I do - in the hands of a terrorist enemy.
Mr. Kerry Weapons of mass destruction, nuclear proliferation. But again, the test of the difference between us: the president's had four years to try to do something about it. And North Korea's got more weapons. Iran is moving toward weapons. And at his pace it'll take 13 years to secure those weapons in Russia.
First, note that Bush said he is mostly concerned about nuclear proliferation in the hands of a terrorist. The boost-phase missile defense system could only be effective, even in principle, against North Korea and Iran (and realistically, probably not against either). The earlier missile defense schemes just don't seem to work. Yet we are spending vast amounts of money on this, and even deploying (or beginning to) a system that just won't work.
On the other hand, as Kerry points out, efforts to control nuclear proliferation in general -- and in particular, securing material in Russia -- are very slow. Here's a link summarizing various proposals for securing nuclear material.
The bottom line is that the cost of the Bush administration's missile defense scheme will be around $1 trillion. On the other hand the current non-proliferation spending is on the order of $2 billion per year (read more here and here). In short, the current administration's plan calls for spending on the order of tens of billions over the next 10 years on controlling nuclear material -- the sort that could fall into the hands of the terrorists Bush sees as the biggest threat to the U.S. -- while spending on the order of 100 times as much (one trillion dollars) on a missile defense system that experts are convinced won't work, and a large part of which could only be effective against a threat from North Korea or Iran. Whether such threats are even realistic is another issue, but even assuming they were, this is nonsensical.
In light of Bush's statement in the debate this seems like a good thing to call him on, and I hope this comes up more in the future debates.Posted by Matt at October 2, 2004 04:41 PM