William Ryan, New Mexico Tech/MRO; Eileen Ryan, New Mexico Tech/MRO
Keywords: Space Situational Awareness, GEO-Satellites, Ground-Based Telescopic Observations, Data Analysis
Abstract:
Satellites inhabiting the geosynchronous zone around Earth are important for basic applications (e.g., world-wide communication, weather monitoring) as well as for national security concerns (e.g., missile launch detection, etc.). As time progresses, satellites launched into the GEO region have gotten smaller, and smaller, making the ability to detect and track decimeter-sized targets at these distances increasingly difficult but important for determining operational status, revealing changes, identifying, and characterizing. In a previous work [1] we reported that the same techniques used for detection and characterization of natural objects such as asteroids and comets can be successfully applied to decimeter-scale artificial targets in the geosynchronous satellite region. We demonstrated that by using the Magdalena Ridge Observatorys (MROs) 2.4-meter telescope, we could detect debris and other objects in GEO at visible magnitudes as faint as V~20 or fainter in single images, and were able to derive reliable and accurate astrometry. We also established that employing strategic shifting and summing of individual images based on the anticipated motion of the target allows for this magnitude limit to be extended somewhat.
Initially, since objects in geostationary orbit typically move about 15 arc-sec per second with respect to sidereal motion, we limited exposure times to half a second or less to avoid significant trailing and analyzed the photometric signatures using circular apertures. For this current work, we explore techniques using elliptical apertures and extend individual exposures to push our detection limits to V~21 visible magnitude and fainter. We investigate the limitations in accuracy inherent in this approach and examine the relative practicalities of utilizing longer individual integration times versus the software shifting and summing of shorter exposures. We also explore the magnitude, and hence size, limitations that these techniques imply for the characterization of artificial objects when studying their temporal photometric and spectroscopic signatures. The MRO 2.4-meter telescopes large aperture and the sites environmental characteristics are ideal for the detection and characterization of small, natural objects in distant orbits, and we will demonstrate that the same can be accomplished for artificial targets.
REFERENCES
[1] Ryan, W.H., and E.V. Ryan (2017). Precision Tracking of Decimeter Targets at GEO Distances using the Magdalena Ridge Observatory 2.4-meter Telescope, Proceedings of the 2017 AMOS Technical Conference, Maui, Hawaii.
Date of Conference: September 17-20, 2019
Track: Space Situational Awareness