H. Cowardin (ESCG/Jacobs Technology), P. Seitzer (University of Michigan), K. Abercromby (California Polytechnic State University), E. Barker (LZ Technology, Inc.), T. Schildknecht (University of Bern)
Keywords: orbital debris, laboratory, optical, photometry
Abstract:
To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC attempts to emulate illumination conditions seen in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. Equipment in the OMC includes a 75-watt Xenon arc lamp, used as a solar simulator; a Santa Barbara Instrument Group CCD camera with standard Johnson/Bessel filters; and a robotic arm, used to simulate an objects position and rotation. The laboratory uses known shapes, materials that are believed to be consistent with the orbital debris population, and three phase angles to best match the lighting conditions of the telescope-based data. The 14 objects studied to-date in the OMC are fragments or materials acquired through ground-tests of scaled-model satellites and rocket bodies, as well as material samples in more or less flight-ready condition. All fragments were measured at 10 increments in a full 360 rotation at 6, 36, and 68 phase angles. This paper will investigate published color photometric data for a series of orbital debris targets and compare it to the empirical photometric measurements generated in the OMC. Using the data acquired over specific rotational angles through different filters (B, V, R, I), multiple color indices are acquired. Using these values and their associated lightcurves, the OMC data are compared to observational data obtained from the 1-m telescope of the Astronomical Institute of the University of Bern, and from the 0.9-m telescope operated by the Small- and Medium-Aperture Research Telescope System Consortium and the Curtis-Schmidt 0.6-m Michigan Orbital DEbris Survey Telescope (MODEST), which are both located at the Cerro Tololo Inter-American Observatory. An empirical-based optical characterization on a subset of fragments will be presented to provide preliminary correlations between laboratory-based and telescope-based data in the context of classifying GEO debris objects.
Date of Conference: September 14-17, 2010
Track: Posters