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Proceedings Paper

Laser-powered multi-newton thrust space engine with variable specific impulse
Author(s): Claude R. Phipps; James R. Luke; Wesley Helgeson
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Paper Abstract

Recently we became interested in applying previous work with liquid fueled laser powered minithrusters for spacecraft orientation to the conceptual design of a multi-newton thruster based on the same principles. Solid-fuel configurations (such as the fuel tapes used in the Photonic Associates microthruster) are not amenable to the range of mass delivery rates (g/s to g/s) necessary for such an engine. We will discuss problems for this design which have been solved, including identifying a practical method of delivering liquid fuel to the laser focus, avoiding splashing of liquid fuels under pulsed laser illumination, and avoiding optics clouding due to ablation backstreaming on optical surfaces from the laser-fuel interaction region. We have already shown that Isp = 680 seconds can be achieved by a viscous liquid fuel based on glycidyl azide polymer and an IR-dye laser absorber. The final problem is mass: we will discuss a notional engine design which fits within a 10-kg "dry mass" budget. This engine, 80kg mass with fuel, is designed to fit within a 180-kg spacecraft, and use 3kW of prime power to deliver a Δv of 17.5 km/s to the spacecraft in sixteen months. Its specific impulse will be adjustable over the range 200sp<3,600 seconds and maximum thrust will be 6N, based on performance which has been demonstrated in the laboratory. Such an engine can put small satellites through demanding maneuvers in short times, while generating the optimum specific impulse for each mission segment. We see no reason why Isp = 10,000 seconds cannot be achieved with liquid fuels.

Paper Details

Date Published: 12 May 2008
PDF: 8 pages
Proc. SPIE 7005, High-Power Laser Ablation VII, 70051X (12 May 2008); doi: 10.1117/12.786459
Show Author Affiliations
Claude R. Phipps, Photonic Associates, LLC (United States)
James R. Luke, Photonic Associates, LLC (United States)
Wesley Helgeson, New Mexico Institute of Mining and Technology (United States)

Published in SPIE Proceedings Vol. 7005:
High-Power Laser Ablation VII
Claude R. Phipps, Editor(s)

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