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Proceedings Paper

Contributions of the OH airglow to space object irradiance
Author(s): John Gruninger; James W. Duff; James H. Brown
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Paper Abstract

We investigated the contributions of the hydroxyl (OH) airglow to the illumination of resident space objects. During nighttime, in a moonless sky, the airglow is the largest contributor to the sky brightness in the visible (vis), the near-infrared (NIR) and short-wave infrared (SWIR) spectral region. The dominant contributors to the airglow are vibrationally excited hydroxyl radicals, OH(ν). The radicals are formed in vibrational states up to υ=9 by the reaction of hydrogen atoms with ozone. The strong emissions, known as Meinel emissions, are sequences with σν= 1-6. Emissions with υ = 3, 4, 5 and 6 occur in the visible and NIR between .4 and 1.0 µm. From 1.0 to 2.5 µm there are very strong emissions from the δν= 2 sequences. The σν= 1 emissions extend into the thermal infrared to 4.5 μm. In this work, we considered four band passes, a vis-NIR band pass, two SABER band passes centered at 1.6 and 2.0 μm, respectively, and a broad band pass around 2.7 µm. SAMM2 was utilized to compute spectra and line of sight radiances. We used line of sight (LOS) radiances to compute the irradiance on a space object that was taken as a flat plate with a Lambertian surface reflectance. Profiles of irradiance versus orientation were calculated. The OH airglow will illuminate a facet even if it is pointing somewhat upward. However, the irradiance in the 2.7 μm band pass comes almost entirely from the atmosphere in the low altitude and the earth emission.

Paper Details

Date Published: 16 October 2007
PDF: 9 pages
Proc. SPIE 6745, Remote Sensing of Clouds and the Atmosphere XII, 67451N (16 October 2007); doi: 10.1117/12.738362
Show Author Affiliations
John Gruninger, Spectral Sciences, Inc. (United States)
James W. Duff, Spectral Sciences, Inc. (United States)
James H. Brown, Air Force Research Lab. (United States)


Published in SPIE Proceedings Vol. 6745:
Remote Sensing of Clouds and the Atmosphere XII
Adolfo Comerón; Richard H. Picard; Klaus Schäfer; James R. Slusser; Aldo Amodeo, Editor(s)

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