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Proceedings Paper

Stand-off molecular composition analysis
Author(s): Gary B. Hughes; Philip Lubin; Peter Meinhold; Hugh O'Neill; Travis Brashears; Qicheng Zhang; Janelle Griswold; Jordan Riley; Caio Motta
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Paper Abstract

Molecular composition of distant stars is explored by observing absorption spectra. The star produces blackbody radiation that passes through the molecular cloud of vaporized material surrounding the star. Characteristic absorption lines are discernible with a spectrometer, and molecular composition is investigated by comparing spectral observations with known material profiles. Most objects in the solar system—asteroids, comets, planets, moons—are too cold to be interrogated in this manner. Molecular clouds around cold objects consist primarily of volatiles, so bulk composition cannot be probed. Additionally, low volatile density does not produce discernible absorption lines in the faint signal generated by low blackbody temperatures. This paper describes a system for probing the molecular composition of cold solar system targets from a distant vantage. The concept utilizes a directed energy beam to melt and vaporize a spot on a distant target, such as from a spacecraft orbiting the object. With sufficient flux (~10 MW/m2), the spot temperature rises rapidly (to ~2 500 K), and evaporation of all materials on the target surface occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a molecular plume in front of the spot. Bulk composition is investigated by using a spectrometer to view the heated spot through the ejected material. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole, and shallow sub-surface composition profiling is also possible. Initial simulations of absorption profiles with laser heating show great promise for molecular composition analysis.

Paper Details

Date Published: 1 September 2015
PDF: 12 pages
Proc. SPIE 9616, Nanophotonics and Macrophotonics for Space Environments IX, 961603 (1 September 2015); doi: 10.1117/12.2186795
Show Author Affiliations
Gary B. Hughes, California Polytechnic State Univ., San Luis Obispo (United States)
Philip Lubin, Univ. of California, Santa Barbara (United States)
Peter Meinhold, Univ. of California, Santa Barbara (United States)
Hugh O'Neill, Ventura College (United States)
Travis Brashears, 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)
Jordan Riley, Univ. of California, Santa Barbara (United States)
Caio Motta, Univ. of California, Santa Barbara (United States)

Published in SPIE Proceedings Vol. 9616:
Nanophotonics and Macrophotonics for Space Environments IX
Edward W. Taylor; David A. Cardimona, Editor(s)

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