Michael Felten, U.S. Air Force; John Colombi, AFIT; Richard Cobb, AFIT; David Meyer, AFIT
Keywords: GEO, SSA, design, optimization, architecture
Abstract:
Maintaining Space Situational Awareness (SSA) of the operational activities in the space domain remains one of the Department of Defenses (DoDs) top priorities. In the ever increasing congested and contested space environment, assuring operators and maintainers have the right mix of sensors to meet SSA requirements is paramount. Current research at the Air Force Institute of Technology (AFIT) has shown that modeling and simulation of Geosynchronous orbit (GEO) SSA architectures can provide utility in identifying optimal combinations of ground and space-based sensors. These SSA architectures were scored in value based on combined sensor performance and total system cost. This paper extends previous GEO SSA research by expanding design boundaries and refining the methodology.
Specifically, for this paper, a GEO SSA scenario was explored. The updated model increased the inherent value of a selected architecture by nearly 50%. This was accomplished through a more refined examination of an increased trade space containing 1022 possible sensor combinations. High-performance computing capabilities allow parallel evaluation of thousands of architecture combinations at once to significantly reduce the wall time when solving large-scale optimization problems. Experimental trials that would have taken over 100 years on a desktop computer were completed in weeks using a high-performance computer containing over 125,000 cores. Discrete telescope aperture sizes, number of telescopes per location, possible ground locations, and satellite orbital regimes were used as inputs for the optimizer. A multi-objective genetic algorithm intelligently searched the trade space to identify optimal executable architectures.
The results of the optimization clearly favored 1.0-meter aperture ground telescopes combined with 0.15-meter aperture sensors in a 12 satellite Geosynchronous Polar Orbit (GPO) constellation. The 1.0-meter aperture ground telescopes have the best cost-performance combination for detecting Resident Space Objects (RSOs) in GEO. The GPO regime offers increased access to RSOs in GEO, without the 40° solar exclusion angle of lower inclination orbits. When performance is held constant, a GPO satellite constellation offers a 22.4% reduction in total system cost when compared to Sun Synchronous Orbit (SSO), Equatorial Low Earth Orbit (LEO), and near-GEO constellations.
The results of the research can be used to educate national policy makers on the costs and benefits of various proposed upgrades to the current and future SSA architectures. The methodology refined through this research has greater utility than simply GEO SSA architecture evaluation; it can be used as a source selection tool to evaluate opposing contractor bids, a simulation tool for efficient evaluation of very large trade spaces, or an analysis workbench for comparison of emerging technologies. Scripting and parallel high-performance computing opens the possibility of solving an entirely new class of problems of interest to the DoD.
Date of Conference: September 11-14, 2018
Track: Space Situational Awareness