Eric C. Pearce, University of Arizona; Harrison Krantz, University of Arizona; Adam Block, University of Arizona; Mitchell Kirshner, University of Arizona; Liam O. Gunter, United States Naval Observatory; Brad Sease, Computational Physics, Inc
Keywords: multi-color, near-IR, spectra, JWST, Breeze-M, SL-12, HS-376, UKIRT, WFCAM, UIST
Abstract:
The characterization of deep space debris poses a significant challenge in Space Domain Awareness (SDA). Multi-color photometry and the resultant color indices offer the potential to rapidly discriminate between debris and intact space objects such as rocket bodies and satellites. These multi-color techniques can also identify anomalous members of object groups and cue higher fidelity data collections and studies. However, multi-color photometry can be difficult to interpret, as the effects of phase and rotation become conflated with the more fundamental material properties of the satellite, and the broad astronomical photometric bands may not identify key spectral features that can be diagnostic for SDA application.
In our previous measurements with the United Kingdom Infrared Telescope (UKIRT) Wide Field Camera (WFCAM), we characterized a wide range of space objects with the goal of developing techniques to rapidly discriminate between different classes of objects and to identify anomalous members of these groups. To date, our survey with WFCAM has produced a comprehensive database of 5-color photometry in the Z, Y, J, H, and K bands, analogous to the bands that are anticipated to be exploited by future U.S. ground based SDA systems. Our current data set includes:
Centaur rocket bodies (RBs)
Molniya communication satellites including the -1K, 1T, -2, and -3 variants
Russian FREGAT and SL-6 upper stage RBs in Molniya orbits
Russian Breeze-M RB disposed in GEO-crossing graveyard like orbits, and the Angara-5/Breeze-M mass simulator, also disposed in a near-GEO orbit
Intact payloads selected from satellites using the Boeing HS-376 bussesincluding four different generations of solar panel technology
Special interest objects, including the JWST and the Chang-e 5 orbiter
During the spring of 2022, we made additional spectral measurements of many of these objects with the UKIRT 1-5 mm Imager-Spectrometer (UIST), providing high fidelity reflectance spectra to better inform our interpretation and analysis of the 5-color photometric measurements. These measurements constitute the most comprehensive collection of near-IR spectra of space objects that have been published. Our targets for UIST observation were carefully selected to include a mix of each of our ensemble groups. The fusion of this data with the previous 5-color photometry in the same bands is a unique opportunity to interpret the 5-color photometry in the context of the higher resolution spectra. Our measurements of the recently launched James Webb Space Telescope (JWST) with both WFCAM and with UIST establishes a baseline spectrum of the JWST sunshade and we anticipate monitoring this object carefully in coming campaigns to study the evolution of its reflectance spectra with time.
Date of Conference: September 27-20, 2022
Track: Non-Resolved Object Characterization