Charles J. Wetterer, KBR; David Strong, Strong EO Imaging, Inc.; Timothy Giblin, i2 Strategic Services LLC; Matthew Fitzgerald, USAFA
Keywords: SDA, Optical System, Calibration, Spectroscopy, Diffraction, Telescope, USAFA, USAFA-1m, GEO Satellites
Abstract:
The United States Air Force Academy (USAFA) has developed techniques to characterize and identify satellites since 2014 using a 16-inch telescope (USAFA-16) on campus as well as off-campus telescopes which comprise the Falcon Telescope Network (FTN). Additionally, USAFA has developed calibration techniques to enable identification of geosynchronous satellites through slitless spectroscopy of satellites. USAFA recently acquired a 1-meter telescope (USAFA-1m) that has not yet been calibrated for spectroscopic measurements of GEO satellites. In this presentation, we report on the effort to calibrate USAFA-1m for spectroscopy. For spectroscopy calibrations we, 1) determine pixel-to-wavelength calibration for the USAFA-1m, 2) determine the spectral response across the focal plane as a function of wavelength, and 3) generate a spectral flat.
The spectroscopy calibrations will utilize a method established and proven on the USAFA-16 and FTN, which involves the capturing of spectral images for known celestial bodies and determining a pixel to wavelength conversion based on the pixel distance between the zeroth and first orders of the diffraction grating image. This conversion can then be applied to GEO satellites to determine characteristics of the spectra they are producing, which can provide insight into qualities of the satellite such as material and color. Additionally, during glint season, the spectral signatures of satellites observed from the USAFA-1m are expected to produce distinct, identifiable profiles which can aid in the classification of the satellites orientation and purpose.
After the calibration for spectroscopy, the USAFA-1m telescope will be capable of satellite characterization akin to that of the FTN, but with greater resolution, a larger focal plane, and greater overall capabilities. The USAFA-1ms wide mirror and larger focal plane should result in the production of more detailed photometry which can be used for the development of new methods for the identification and characterization of GEO satellites. We expect the USAFA-1m will be capable of furthering USAFAs research into the characterization of GEO satellites based on their spectral signatures, furthering our SDA efforts and our ability to develop new techniques to identify orbiting objects in our space domain.
Date of Conference: September 19-22, 2023
Track: SDA Systems & Instrumentation