NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Spectral infrared hemispherical reflectance measurements for LDEF tray clampsThis paper describes infrared hemispherical reflectance measurements (2-15 microns) that were made on 58 chromic acid anodized tray clamps retrieved from the LDEF spacecraft. These clamps were used for maintaining the experiments in place and were located at various locations about the spacecraft. Changes in reflectance of the tray clamps at these locations were compared with atomic oxygen fluxes at the same locations. A decrease in absorption band depth was seen for the surfaces exposed to space indicating that there was some surface layer erosion. In all of the surfaces measured, little evidence of contamination was observed and none of the samples showed evidence of the brown nicotine stain that was so prominent in other experiments. Total emissivity values were calculated for both exposed and unexposed tray clamp surfaces. Only small differences, usually less than 1 percent, were observed. The spectral reflectances were measured using a hemi-ellipsoidal mirror reflectometer matched with an interferometer spectrometer. The rapid scanning capability of the interferometer allowed the reflectance measurements to be made in a timely fashion. The ellipsoidal mirror has its two foci separated by 2 inches and located on the major axis. A blackbody source was located at one focus while the tray clamp samples were located at the conjugate focus. The blackbody radiation was modulated and then focused by the ellipsoid onto the tray clamps. Radiation reflected from the tray clamp was sampled by the interferometer by viewing through a hole in the ellipsoid. A gold mirror (reflectance approximately 98 percent) was used as the reference surface.
Document ID
19920018052
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wood, Bobby E.
(Calspan Corp. Arnold AFS, TN., United States)
Cromwell, Brian K.
(Sverdrup Technology, Inc., Arnold AFS TN., United States)
Pender, Charles W.
(Sverdrup Technology, Inc., Arnold AFS TN., United States)
Shepherd, Seth D.
(Air Force Systems Command Arnold AFS, TN., United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1992
Publication Information
Publication: NASA. Langley Research Center, Second LDEF Post-Retrieval Symposium Abstracts
Subject Category
Optics
Accession Number
92N27295
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available