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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.
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UNCLASSIFIED/ il"9" 91"l"!e!lltt tl!IL 9HL I An outline of the conceptual design features of the proposed 10 MW electron gun-driven CO2/gas mixture laser is [29]: • Scalability of total beam output power, beam combining concept. • Power oscillator or master oscillator-power amplifier (MOPA) design. • Unstable optical resonator cavity with grating and rotating mirrors beam-combine techniques. • Flow and gas handling system with blow down and exhaust to the atmosphere. • Acoustics suppression with expansion horn downstream and anode muffler. In this concept there are four separate laser transmitters each generating 2.5 MW output beams that are combined into a single 10 MW output beam. The oscillator parameters for each beam transmitter are [29]: • Energy loading, Ep: Ep = 300 J (higher loadings at reduced gas temperature); gain volume = 0.27 m 3 (x 4 lasers); A to K = 0.3 m; gain length = 3 m. • Specific laser output = 65 J/1. • Estimated extraction efficiency = 20%. • Pulse repetition rate: 125 Hz@ 20μs. • Laser power, P = 2.5 MW/beam x 4 beams = 10 MW. • Laser energy per pulse = 18 kJ/beam x 4 beams = 72 kJ. • Output wavelengths: 10.6 ~tm, 10.2 ~tm, 9.6 ~tm, and 9.3 μm (mixed). • Gas mixture ratio (for N2:CO2:H2): 3:1:0.08. • Gas pressure = 1.013 x 10 5 Pa (or 1 atmosphere). • Flash factor= 1.3. The optical resonator cavity and optical components specifications are [29]: • Resonator type: confocal unstable with rotating mirrors beam combining. • Magnification, M = 4. • Cavity length, L = 36.5 m. • Equivalent Fresnel number = 3.4. • Cavity end mirrors radius of curvature: RMirror1 = 97.3 m (concave), RM1rror2 = 24.3 m (convex). • Gain cell: volume= 0.3 x 0.3 x 3.0 m 3 , length= 3 m. • Beam combine mirrors: 75 x 75 cm 2 flat (30 x 30 cm 2 apertures) @ f. = 10.59 ~Lm. • Low pressure hot cell: 0.3 to 0.5 GHz suppression near line center. • Output scraper mirror: D = 0.075 m (taped). See Figure 16 and Figure 17 for schematics of the power oscillator optics and the MOPA. The laser operation requirements for the gas flow system are (see Figure 18) [29]: • Flow System: blow down. • Gain Section • Cross-section, A= 0.3 m x 3.0 m = 0.9 m 2 . • Volume, V = 0.3 m x 0.3 m x 3.0 m = 0.27 m 3 . • Flow speed, u = SO m/sec (@ 125 Hz & flash factor= 1.3). • Dynamic pressure, !'..P = 2000 Pa (or 0.02 atmospheres). • Mass flow rate, Q = 60 kg/sec per module ( 45 m 3/sec std). • Run time, t = 300 seconds 43 UNCLASSIFIED/;«F&lil 8FFI@Itllt 1!!191! SHLY
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 77 pages are in the text index: search them above, or from the library's search.