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Many Lasers Become One In Lockheed Martin's 30 kW Laser Weapon
Zothecula writes "In another step forward for laser weapons that brings to mind the Death Star's superlaser, Lockheed Martin has demonstrated a 30-kilowatt fiber laser produced by combining many lasers into a single beam of light. According to the company, this is the highest power laser yet that was still able to maintain beam quality and electrical efficiency, paving the way for a laser weapon system suitable, if not for a Death Star, for a wide range of air, land, and sea military platforms."
Too many unknowns to get exact numbers, but assuming visible light and 10cm aperture, we are probably talking about few mm per each km of distance. Geostationary satellites are completely out of range, but lets take ISS as example - 400km. This means that 30kW would be spread over circle with 2m or so. ISS has a speed of 7-8km/s (as all low orbit satellites, otherwise they would fall down). This means that each part of station would be in the beam 'focus' for 0.005 seconds. Given radius of the beam and speed, there would be no localized damage - just total energy transferred to station. Assuming it goes in most unfavorable way, it can probably get around 100m of length through the beam, giving a total of 0.013s exposure. So, in most unfortunate situation, we are talking about 390 joules of energy being transferred to the ENTIRE station. For comparison, light shining on _earth_ hits with 1000 joules per second for each square meter (a probably a lot more in space). So, we are talking about effect being few hundred times smaller than sun radiation station received each second.
Please note that we are talking about _collateral_ damage due to missed shots, not active tracking of satellites. But even with perfect tracking and a lot more powerful lasers, it would be very hard to do lasting damage. Current anti-satellite laser developments are about _blinding_ satellites, not blowing them up.
If you think that collateral, non-tracked shot from realistic laser with 30kW of power can do any damage to any satellite, please provide your calculations. Otherwise, too much watching StarWars, not enough science.