Drone-Mounted Laser Weapons Are On the Way
Daniel_Stuckey writes "DARPA is funding research into drone-mounted laser weapons. The project, called Endurance, is referred to in DARPA's 2014 budget request as being tasked with the development of 'technology for pod-mounted lasers to protect a variety of airborne platforms from emerging and legacy EO/IR guided surface-to-air missiles.' The budget explains that it will be the first application of DARPA's much-discussed Excalibur laser defense system, which developed lasers powerful enough to use as weapons. With the new program, DARPA is focused on miniaturizing the technology, as well as 'developing high-precision target tracking, identification, and lightweight agile beam control to support target engagement. The program will also focus on the phenomenology of laser-target interactions and associated threat vulnerabilities." In other words, DARPA hopes that drone-mounted lasers will soon be able to shoot missiles out of the sky."
Seeing as they specifically mention Electro-Optical and Infra-Red guided missiles, It seems that the objective is not to 'blow up' a missile as the linked article suggests, but rather to use a laser to blind the missile's tracking systems, causing it to lose tracking and veer off target or "generate a miss" as they say.
Getting a laser to destroy a missile requires about 100 kW of energy and a few tons of hardware to focus it.
Getting a laser to blind optical sensors requires a $10 Radio Shack gift card.
Any sort of adjustable mirror designed to reflect lasers seems like it would have a huge impact on missile aerodynamics.
You'd also need to make sure the mirrors stay very clean throughout flight... condensation or dust would absorb the laser's energy and begin melting the mirror underneath. There's also issues with matching the mirror to the wavelength of the laser, the fact that no mirror reflects 100% of light and any distortions in the mirror could make it worse.
You'd be better off with some sort of ablative armor on the missile.