Aaron J. Rosengren, University of Arizona
Keywords: Space debris; High area-to-mass ratio objects; Disposal orbits; Celestial mechanics; Dynamical evolution and stability; Orbit perturbations; Disposal orbits
Abstract:
The solution to the debris proliferation problem, brought on by decades of unfettered space activities, can only be found by coupling mitigation and remediation methods with a deeper understanding of the dynamical environments in which these objects reside. Recent efforts towards this more heuristic approach have explored passive means to curtail the growth rate of the debris population, by seeking to cleverly exploit the dynamical instabilities brought on by resonant perturbations, to deliver retired Earth-orbiting satellites into the regions where atmospheric drag can start their decay. Recent work has uncovered a devious network of lunisolar secular resonances permeating the medium-Earth orbits of the navigation satellite constellations, inducing especially strong changes on the orbital eccentricity, which could be increased to Earth-reentry values. These results have put forward the idea that similar phenomena could manifest themselves throughout all circumterrestrial space, from very low-altitude orbits up to the geostationary ring and beyond.
Here, we show that orbital resonances, associated with commensurabilities among the frequencies of the perturbed motion, occur in profusion within the whole of the circumterrestrial phase space, in both dissipative and Hamiltonian settings. In this talk, we will present a complete dynamical atlas of the entire usable space from LEO to GEO, characterizing the long-term evolution of resident space objects. Active debris removal, apart from the daunting obstacles in practical engineering and the difficult financial, political, and legal challenges that it represents, is widely seen by the debris community as the only suitable option to prevent the self-generating Kessler phenomenon. Such drastic measures, however, should be reassessed on account of our increasing knowledge on the long-term effects of the principal resonances in near-Earth space. We will show that many of these orbital resonances can be exploited on decadal timescales to effectively remove satellites from crowded regions and their long lifetime orbits. We will link our cartographic stability maps to the appropriate disposal strategy or deorbiting device for any operational orbit, and highlight how such dynamical assessments can have a tangible influence on debris mitigation though the passive debris removal ideology.
A permanent debris-control scheme, based more on remediation than mitigation, will have to be developed well in advance of the critical orbit-clogging point predicted by Kessler. The proper definition of the end-of-life strategy that takes into account the long-term dynamics, in conjunction with relatively low-cost maneuvers or an area-to-mass-ratio-augmenting device (e.g., solar sail), from the early design phase can possibly yield a self-correcting mechanism, much needed to sustain the space environment. In this regard, choosing the most effective strategy able to drive a given satellite towards a reentry solution must be based on a deeper understanding of the natural dynamical environment of the specific orbital regions. This talk will link theoretical aspects of resonant and chaotic dynamics with the practical application of passive debris removal, and lay an essential logical foundation for future developments. Further studies in this area may lead to deeper insights in astrodynamics, with broad implications for space situational awareness, as well as provide practical results for satellite technology.
Date of Conference: September 11-14, 2018
Track: Optical Systems Instrumentation