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Welcome to our overview of the ongoing research and development related to Space Situational Awareness (SSA) by our research team at the University of Arizona Steward Observatory. Our team specializes in the development of unique instrumentation and astronomical techniques tailored to the unique challenges of satellite tracking and characterization. In many cases, our research can also be applied to challenging astronomical measurements and survey astronomy.
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The Pomenis AstrographP.I. Dr. Eric C. Pearce, Steward ObservatoryThe Pomenis Astrograph System as an alternative to more traditional narrow field of view small SSA systems. The astrograph is innovative with its fast optical design versus a traditional longer focal length found on commercial Cassegrain telescope commonly used on small COTS SSA systems. Compared with other systems used for SSA, the Pomenis astrograph has an exceptionally wide 5-degree field of view and a fast readout CCD camera. These features enable synoptic survey of the deep space satellite population several times per night. The aperture and focal length were carefully selected to achieve sensitivity relevant to synoptic GEO SSA with an integration time short enough to allow high precision astrometric reference using the streaked background stars.
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The Pomenis Enclosure (the "Dog House")P.I. Harrison Krantz, Steward ObservatoryThe Dog House is a trailer mounted telescope enclosure designed to allow periodic relocation of Pomenis between our three mountaintop sites. We can take Pomenis on trips to schools and other public shows. The team is completing the integration of the motors, controls, and CCTV to allow remote autonomous operations.
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Chimera is a high-speed photometer with simultaneous three-color photometry in the Sloan r’ (562-695 nm), i’ (695-844), and z’ (826-920 nm) bands. The wide field of view facilitates acquisition and tracking of rapidly moving satellites and allows for a variety of photometric calibration methods. For space surveillance, the optical signature characteristics of rapidly rotating satellites necessitate the use of high-speed multicolor photometers. Satellite photometric analysis takes advantage of reflections off flat surfaces of the satellite. The duration of these flashes are as short as a few ms. The high frame rate of Chimera allows detailed study of the temporal profile of these reflections, which will allow assessment of the quality and characteristics of the reflective surfaces.
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Photometric Processing PipelineP.I. Dan Avner, Steward ObservatoryThe photometric processing pipeline for Chimera is a highly modified version of the pipeline originally developed by Michael Momert for asteroid photometry. Our modifications include adapting the pipeline for the high frame rates, three simultaneous channels, higher non-sidereal rates associated with satellite photometry.
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Night Sky Brightness MonitoringP.I. Dr. Eric C. PearceOur Night Sky Brightness (NSB) monitoring program uses the unique attributes of the Pomenis Astrograph system to rapidly collect full hemisphere sky brightness measurements rapidly. These measurements allow us to quantify the sky brightness not only at zenith, but near the horizon both towards and away from nearby population centers. Such measurements allow us to validate NSB models, monitor the impact of population growth and light pollution control measures at our observatory sites.
The Pomenis Astrograph takes sky brightness measurements with the primary camera in up to seven photometric bands (usually Sloan g', r', i', z', and LGOT w). The system has been outfitted with two Unihedron Sky Quality Meters (SQMs), one co-aligned with the telescope, and one fixed at zenith to measure sky stability during the full-hemisphere collections. |
Photometric Satellite CharacterizationP.I. Dr. Eric C. PearceThe characterization of deep space debris has posed a significant challenge in SSA. For SSA, characterization must be performed quickly and under non-ideal operational conditions, generally using non-resolved techniques. The use of multi-color photometry and the resultant color indices in the near and short-wave IR offer the potential to rapidly discriminate between debris and intact space objects such as rocket bodies and satellites. The color indices surrounding the near-IR Z band (0.83-0.925 µm) show promise to differentiate materials while providing a more practical data collection opportunity when compared to spectroscopy. Similar techniques have been demonstrated in the astronomical community to discriminate between different classes of near Earth asteroids. The diagnostic attributes of the Z band are particularly compelling as similar diagnostic color indices can be measured using visible telescopes and the corresponding Sloan z’ band. In support of this research, the team uses data collected by Chimera on the Steward Observatory Kuiper 61" Telescope and five-color near IR data collected with the UKIRT Wide Field Camera (WFCAM).
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