Analysis of Spacecraft Materials Discrimination Using Color Indices for Remote Sensing for Space Situational Awareness

The increasing number of space missions have resulted in an augmented density of artificial objects positioned in orbital
domains near Earth. Knowing the material composition of the resident space object can be of value in object identification
and risk assessment using remote sensing techniques. To perform this task, it is increasingly imperative to optically
characterize spacecraft materials to identify unique material-specific spectroscopic markers. In this work, a variety of
materials frequently utilized by the aerospace industry in spacecraft design and construction were analyzed using
reflectance spectroscopy. The collected data provide a spectral characterization baseline for modern-day and historical
spacecraft materials. The color index was computed for standard astronomical and suggested theoretical filter passbands
and compared to each other in their capability to discriminate materials belonging to different classes. The color index was
calculated from reflectance spectra of common spacecraft materials in their pristine, as-received conditions that fell under
different family groupings. Different color-index combinations were studied using color-color diagrams. Visual and
quantitative analysis of the color-color diagrams were used to evaluate the possibility of discriminating materials from one
another by means of optical measurements. Results of the analysis show that polyimide and photovoltaic materials are
most easy to discriminate from all other materials via color indices using different filter passbands evaluated in this study.