Apparently ground based lasers (GBLs) can be used to induce short circuits between solar cells on some satellite arrays. The vulnerability does not exist in the arrays used on U.S. Milsats (military satellites).

Ground based laser triggered discharges on satellite solar arrays

. An emerging airborne laser (ABL) threat to commercial and scientific space telescopes is described.Techniques for hardening commercial satellites against ABLs and ground-based lasers are presented. © 2014Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.OE.53.9.095105] Keywords: airborne laser; anti-satellite; cat’s eye effect; high-energy laser; high-power laser.Paper 131931 received Dec. 24, 2013; revised manuscript received Jul. 8, 2014; accepted for publication Aug. 22, 2014; publishedonline Sep. 11, 2014. 1 IntroductionIn a previous paper, 1 I described how commercially avail-able, hydrogen fluoride, pulsed ground-based lasers(GBLs) could be used to damage the solar arrays onsome satellites. Damage from continuous wave (CW) andhigh-pulse-rate (HPR) GBLs was not considered becausethere were expectations 2,3 but no useful data regardinghow well adaptive optics (AO), location, and good seeing 1 mitigated the otherwise very deleterious effects of wholebeam thermal blooming on CW and HPR high-powerlaser (HPL) propagation from ground to space. PulsedGBLsarenotaffectedbywholebeamthermalbloomingpro-vided the pulse width is not much greater than 10 μs and thepulse rate is not much greater than 1 Hz.

Airborne laser threat to commercial space telescopes

A method is described for hardening GEO missile warning satellites against jamming by airborne lasers with wavelengths out-of-band to the satellite’s sensor. The lasers jam by heating the telescope optics to temperatures where the glow from the optics masks the signal from missile plumes. Cooling the relatively isolated scan mirror near the aperture of the telescope is a particular concern. Connecting cooling pipes to it could interfere with its motion. Spraying a cold gas on it could cause contamination. Here thermal radiation transport theory is used to show that cooling the walls of the fore-optics enclosure to ~ 130 K during an attack will adequately cool the scan mirror and protect the sensor from thermal jamming.

Hardening GEO missile warning satellites against thermal jamming by out-of-band airborne lasers

The U.S. Navy's most advanced laser weapon looks like a pricey amateur telescope. As it emerges from a chassis high on the USS Ponce to look out onto the daytime sky above the Persian Gulf, its operator sits in a darkened room elsewhere on the ship holding what looks like a game controller. The screen before him is showing a small boat floating near the Ponce, carrying a dark object. The infrared beam hitting the object is invisible, but you can see one spot grow brighter until the object suddenly explodes, sending metal shards spiraling into the water.

The ray guns are coming

The paper discusses the design, analysis, and testing of a rapidly cooled beryllium cryogenic mirror, which is the primary mirror in the four-element optical system for the Long Wavelength Infrared Advanced Technology Seeker. The mirror is shown to meet the requirement of five minutes for cooling to cryogenic operating temperature; it also maintains its optical figure and vacuum integrity and meets the nuclear specification. Results of a detailed thermal analysis on the mirror showed that, using nitrogen gas at 80 K as coolant, the front face of the mirror can be cooled from an initial temperature of 300 K to less than 90 K within five minutes. In a vacuum chamber, using liquid nitrogen as coolant, the mirror can be cooled to 80 K within 1.5 min. The mirror is well thermally insulated, so that it can be maintained at less than its operating temperature for a long time without active cooling.

Design of a rapidly cooled cryogenic mirror

Methods are proposed for hardening a missile warning satellite against jamming and damage from unlimited running time 1-MW airborne, 1-MJ ground-based, and space-based lasers. The unhardened telescope design is based on a model of a missile warning satellite telescope developed by the American Physical Society Study Group on Boost-Phase Intercept Systems for National Missile Defense. The APS telescope can step-stare or linearly scan. In response to an attack, laser warning devices can close a shutter at the first focal surface. Filter wheels in a collimated section of the optical path, insert filters to protect focal plane arrays and readout ICs from jamming and damage. Neutral density filters are inserted to assess threats. The shutter is reopened. The reduced laser intensity in the collimated section protects the filters. The field of view (FOV) is reduced with a field stop wheel, with differently sized apertures, to allow the system to step-stare between multiple jammers in the normal FOV. A cryogenic gas cools fore-optics heated by lasers or by X-rays from nuclear bursts.

John R. Solin

Papers

Hardening a notional missile warning satellite telescope against jamming and damage by ground, airborne, and space-based lasers