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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 1 November 2010, was produced under the Advanced Aerospace Weapon System Applications (AAWSA) Program. It describes nanosatellite technologies and proposes launching nanosats into orbit with laser Lightcraft propulsion. It also covers a weapon mission selection study and multi-megawatt laser options. The author recommends that the Department of Defense and NASA bring Lightcraft R&D back to the United States and restart the X-50LR flight demonstration program.
“Low Earth orbit”7 pages
UNCLASSIFIED/ /f81il 8FrI@Itllt ""I! one I • Average power limited by low thermal conductivity of host material. • Wavelengths propagate extremely well in clear weather: - Very low absorption. - Higher scattering. The requirements for high average power bulk solid-state lasers are [30]: • Efficient optical pumping of gain medium: - Flash lamp or laser diode well matched to absorption band. - Small wavelength difference between pump and lasing ➔ low quantum defect. • Efficient heat removal from gain medium: - Improved heat removal techniques from host. - Large surface area per unit volume. - Or, large volume to store heat with low duty cycle operation. • Gain medium must retain good (correctable) optical quality. The typical properties of widely used Nd :YAG lasers are [30]: • 4 nm absorption line width. • 24% heating from quantum loss. • Saturation intensity:::: 3 kW/cm 2 (at:::: 2% dopant). • Multi-kilowatt average power demonstrated. • Maximum average power potential ~ several hundred kilowatts: - Heat removal makes continuous running a challenge at this power. - Current high-energy SSLs produce great amounts of heat (e.g., 600 kW of electrical power in and 100 kW of beam power out equals 500 kW of waste heat). - Must store the waste heat and reject it from the system at a lower rate, thus requiring storage and limited duty cycle. • Quantum defect= pump light photon energy minus laser light photon energy. The typical properties of widely used Yb:YAG lasers are [30]: • 18 nm absorption line width. • Indium gallium arsenide (InGaAs) pump laser diodes at 0.941 μm wavelength: - 8.6% heating from quantum loss. • Saturation intensity:::: 9.7 kW/cm 2 (at:::: 25% dopant). • Multi-kilowatt average power demonstrated. • Maximum average power potential is perhaps 5 x Nd:YAG laser. A new technology that enables the scaling-up of BSSSL beam power is a recently developed thermal management system that is used to remove and store the waste heat produced by BSSSL devices. General Atomics' Advanced Power Systems Division recently announced* that it has completed testing of an advanced thermal energy ·Reported in Space War Newsletter, June 7, 2010. 51 UNCLASSIFIED/ ;CFQA: QFFI&I.«tk Wlil!! 8Hkl/
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 77 pages are in the text index: search them above, or from the library's search.