Space-Based Visible Space Object Photometry: Initial Results

Abstract

One of the objectives of the Midcourse Space Experiment surveillance experiments is to collect photometric and radiometric data on a selected set of resident space objects from the long-wavelength infrared through the short wavelength ultraviolet region of the spectrum. This was done using the Spatial Infrared Imaging Telescope III, Space-BasedVisible (SBV),ultravioletandvisibleimager,andspectrographicimagerinstrumentpackagesonboard thespacecraft. Analysis of these data will primarily emphasize 1 )construction and validation of phenomenological models for a broad range of resident space object classes, for example, spin- and three-axis stabilized satellites, rocket bodies, and orbital debris, over a wide range of solar phase angles and 2 ) discrimination between classes of resident space objects and identie cation of discriminating characteristics within a resident space object class. We concentrate on the initial results from the SBV instrument. We provide an overview of the surveillance data collected to date, discuss its limitations, and present examples of the data collected on two classes of resident space objects. Nomenclature Ap = projected area of resident space object, m 2 B i V = stellar color index Mv = Johnson V-band visual magnitude MSBV = Space-Based Visual (SBV) magnitude R = range, m d sun = solar declination angle W = off-specular angle w = Midcourse Space Experiment parallax angle