In 2014, NASA’s Orbital Debris Program Office (ODPO) gained access to the United Kingdom Infrared Telescope (UKIRT) for orbital debris research. Lockheed Martin Space Systems was awarded a NASA contract to assume operations of this extremely productive telescope with the University of Arizona. An unprecedented one-third of this telescope’s time has been allocated for the NASA ODPO Optical Measurements Group (OMG) to collect orbital debris data over a 2-year period. This new asset increases the spectral and geographical coverage of geosynchronous orbital debris objects available to the OMG.
UKIRT is a 3.8 m telescope located on Mauna Kea, Hawaii (Figure 1). At nearly 14,000 feet, this location is one of the premier astronomical sites due to its altitude, exceptionally dry air (often 5-10% humidity or lower) and distance from light pollution.
Using UKIRT’s five available instruments, the ODPO’s spectral coverage extends into the near- (0.8-5 µm) and the mid- to far-infrared (8-25 µm) regimes (Figure 2). Analysis of lowand high-resolution spectroscopy as well as photometry yields insights into the reflectance properties of debris across these wavelengths, useful for characterizing the physical properties of objects. Absorption bands in spectra can be used to infer materials comprising debris targets, while combining reflected and thermal IR responses leads to estimates of an object’s size. The combination of all these capabilities is critical for understanding the threat debris poses to active satellites.
The combination of this ground-based telescope with optical telescopes, including the Meter Class Autonomous Telescope (MCAT) on Ascension Island (under construction) and telescopes in Chile, yields spectral coverage ranging from 0.3 – 25 µm (Figure 3). Through access to these telescopes, orbital debris is now being studied in depth across a wider wavelength range in the visible and IR than ever previously studied by ODPO. When combined with either catalogued or simultaneously obtained visible photometry, changes in the objects’ albedo across the electromagnetic spectrum will provide further insight into material types and sizes. By expanding the methods for surveying, detecting, and characterizing orbital debris, we can better model the debris environment and ultimately gain insight into how to mitigate potential collisions for future missions .
1. Lederer, S., et al. NASA’s Newest Orbital Debris Groundbased Telescope Assets: MCAT and UKIRT, 2014 AMOS Technical Conference Proceedings, 2014.
Original article posted in the Orbital Debris Quarterly News, Vol. 19, Iss. 1, January 2015.