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Proceedings Paper

Remote laser evaporative molecular absorption spectroscopy
Author(s): Gary B. Hughes; Philip Lubin; Alexander Cohen; Jonathan Madajian; Neeraj Kulkarni; Qicheng Zhang; Janelle Griswold; Travis Brashears
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Paper Abstract

We describe a novel method for probing bulk molecular and atomic composition of solid targets from a distant vantage. A laser is used to melt and vaporize a spot on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption occurs as the blackbody radiation passes through the ejected plume. Bulk molecular and atomic composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected plume. The proposed method is distinct from current stand-off approaches to composition analysis, such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes target material and observes emission spectra to determine bulk atomic composition. Initial simulations of absorption profiles with laser heating show great promise for Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy. The method is well-suited for exploration of cold solar system targets—asteroids, comets, planets, moons—such as from a spacecraft orbiting the target. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole or trench, and shallow subsurface composition profiling is possible. This paper describes system concepts for implementing the proposed method to probe the bulk molecular composition of an asteroid from an orbiting spacecraft, including laser array, photovoltaic power, heating and ablation, plume characteristics, absorption, spectrometry and data management.

Paper Details

Date Published: 19 September 2016
PDF: 12 pages
Proc. SPIE 9981, Planetary Defense and Space Environment Applications, 99810J (19 September 2016); doi: 10.1117/12.2242730
Show Author Affiliations
Gary B. Hughes, California Polytechnic State Univ., San Luis Obispo (United States)
Philip Lubin, Univ. of California, Santa Barbara (United States)
Alexander Cohen, Univ. of California, Santa Barbara (United States)
Jonathan Madajian, Univ. of California, Santa Barbara (United States)
Neeraj Kulkarni, Univ. of California, Santa Barbara (United States)
Qicheng Zhang, Univ. of California, Santa Barbara (United States)
Janelle Griswold, Univ. of California, Santa Barbara (United States)
Travis Brashears, Univ. of California, Santa Barbara (United States)


Published in SPIE Proceedings Vol. 9981:
Planetary Defense and Space Environment Applications
Gary B. Hughes, Editor(s)

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