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| Science & Technology |
| Military High Powered Lasers Facing Heat Problems |
| 2009-07-12 |
| HIGH-ENERGY laser weapons have been hailed as the future of anti-missile defence, but they may be further from being battle-ready than military chiefs hoped. In recent tests, several prototypes have suffered serious damage to their optics at intensities well below the expected levels of tolerance. "Optical damage has been quietly alarming upper management in most major programmes," Sean Ross of the US Air Force Research Laboratory in New Mexico told a meeting of the Directed Energy Professional Society in Newton, Massachusetts, last week. There are also big problems managing the waste heat generated by high-intensity beams. Laser weapons require mirrors and lenses to focus powerful beams onto distant moving targets, and to compensate for atmospheric perturbations that can reduce the power they deliver. The higher the intensity of the beam, the more likely it is to damage the surface of its optical components. Optical surfaces are designed to withstand powers up to a specific damage threshold, but tiny flaws or irregularities - which can be extremely difficult to spot - reduce this threshold by making them more vulnerable to heat. Contaminants deposited on the surface can also reduce this threshold by forcing the surface to absorb energy. These problems have begun to stall the development of laser weapons. Earlier this year in the US, engineers halted tests of the $4.3 billion megawatt-class Airborne Laser short of full power to avoid damaging "a handful of optics in the turret", according to Mike Rinn, a Boeing vice-president who manages the programme. They realised that the optics, designed years ago, would be "frail" in the presence of any contamination, which would be virtually inevitable in flight. In the next week or so, Boeing engineers will install replacement optics and test them on the ground before running the laser at full power in flight. Finding a way of preventing laser weapons from frying themselves is proving just as troublesome. Depending on the type of laser, generating 1 watt of laser beam produces about 4 watts of waste heat that must be dissipated. The challenge is to develop a cooling system that is both small and extremely robust. |
| Posted by:Anonymoose |
| #8 A network of smaller lasers would appear to be the solution. But they would have to be ground based, which is unlikely to appeal to the Airforce. One thing the Soviets got right was to have a separate Strategic Rocket Force. |
| Posted by: Phil_B 2009-07-12 20:37 |
| #7 Especially if you are the target. |
| Posted by: Hellfish 2009-07-12 19:46 |
| #6 Military High Powered Lasers Facing Heat Problems Well DUH. |
| Posted by: Redneck Jim 2009-07-12 18:38 |
| #5 Just have more lower power beams focussed on one spot. |
| Posted by: Bright Pebbles 2009-07-12 16:58 |
| #4 I dont think this will be fixed until they find a way to get rid of the mirrors. Any tiny spec of dust on one of the mirrors will absorb a tremendous amount of energy and create a burn spot on the optics. This means that assembly and (most importantly) maintenance can only be done in clean-room conditions. So they either need to put the mirrors in a closed assembly that can be swapped out and maintained as a module or get rid of the mirrors and find some other way of controlling the beams. |
| Posted by: crosspatch 2009-07-12 15:32 |
| #3 The solution is airborne squeegee men. Since unemployment is near 10%, there should be plenty of applicants. |
| Posted by: ed 2009-07-12 11:06 |
| #2 Mr. Edison had quite some problem with the filaments for his 'light bulb' suffering heat damage. I belive he was eventually successful in engineering a solution. |
| Posted by: SteveS 2009-07-12 10:49 |
| #1 Interesting but this is just another Engineering and Materials problem. Just getting to where they are now was the challenge. |
| Posted by: tipover 2009-07-12 10:35 |