Tuesday, May 6, 2008

Update: Question for Readers

Recently, yours truly posited a question for Nukes of Hazard readers regarding the Airborne Laser (ABL). At the April 16 House Subcommittee on National Security and Foreign Affairs hearing on missile defense (a summary can be found here), Philip Coyle claimed that "if the enemy paints their missiles with an ordinary white paint, a white paint that is 90% reflective to the [ariborne] laser, then 90% of the laser energy bounces off." Missile Defense Agency (MDA) spokesman Rich Lehner disputed this characterization, arguing that:

Regarding the paint, not true....That the U.S. would spend more than 4 billion on a weapon system that could be defeated by a coat of paint might make a good sitcom but has no basis in fact.
An anonymous commenter seemed to agree with Lehner, "the Airborne Laser is infrared, so color should have no effect on it."

At the most recent House Subcommittee on National Security and Foreign Affairs hearing on missile defense (a summary can be found here), Coyle stood by and expanded upon his earlier comments about the ABL. According to Coyle:
It would have been more accurate if the MDA Public Affairs Director had written, '...spend more than $8 billion on a weapon system that could be defeated...,' rather than '...spend more than $4 billion on a weapon system that could be defeated...' According to the GAO, if the Congress supports the MDA budget request through FY 2013 the ABL program would spend over $8 billion in 2008 constant dollars.
On the matter of the paint, Coyle noted:
...missiles painted with dark colors will absorb almost all of the laser energy and only 10% will be reflected. For missiles painted with an ordinary white paint, a white paint that is 90 percent reflective to the laser, 90 percent of the laser energy bounces off. Missiles with polished aluminum surfaces can reflect about 95% of the energy. Special coatings can raise reflectivity further, to 98% and more.
Coyle went on to argue that enemy missiles that rotate and the presence of "an ablative coating that burned off the outside of the enemy missile" could also compromise the effectiveness of the ABL.

Anyone have any further thoughts on this? I'm still waiting to hear from a few "experts" on this issue, so I'll be sure to report back what I find out.

3 comments:

nucleardreams said...

...not true....That the U.S. would spend more than 4 billion on a weapon system that could be defeated by a coat of paint might make a good sitcom but has no basis in fact.

I agree. The US would spend billions only on missile defense that can be foiled by simple countermeasures. However, all this would definitely make a good sitcom, no argument about that.

Stephen said...

Like so many things about ballistic missile defense, these arguments are nothing new. They first surfaced twenty-five years ago when the Reagan administration's proposed, as part of the Strategic Defense Initiative, space-based laser platforms to knock out Soviet ICBMs in the boost phase.

Then, as now, missile defense advocates brushed aside such criticism and insisted that given enough time and money, the systems would work.

Anonymous said...

Again, any coating must be reflective at the wavelength the laser operates at, which is in the near-IR in the case of the ABL. "Simple white paint" does not reflect 90% of near-IR energy and neither does "polished aluminum," particularly when one considers the high energy state of the photons hitting the material. It's hard to see how someone with Mr. Coyle's resume could so easily mistake visible light reflectivity with IR reflectivity as if they are equivalent. There is no direct equivalence to visible color and IR reflectivity.

Mr. Coyle also makes an ablative coating more easy that it actually is. Such coatings are heavy and weight is a huge limitation for ballistic missiles, not to mention the changes in a missile's center of gravity and aerodynamic characteristics an ablative coating would create.