Collision Avoidance Operations in a Multi-Mission Environment
AIAA 2014-1745 SpaceOps Conferences 5-9 May 2014, Pasadena, CA Proceedings of the 2014 SpaceOps Conference, SpaceOps 2014 Conference Pasadena, CA, USA, May 5-9, 2014, Paper DRAFT ONLY AIAA 2014-1745. Collision Avoidance Operations in a Multi-Mission Environment Manfred Bester,1 Bryce Roberts,2 Mark Lewis,3 Jeremy Thorsness,4 Gregory Picard,5 Sabine Frey,6 Daniel Cosgrove,7 Jeffrey Marchese,8 Aaron Burgart,9 and William Craig10 Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 With the increasing number of manmade object orbiting Earth, the probability for close encounters or on-orbit collisions is of great concern to spacecraft operators. The presence of debris clouds from various disintegration events amplifies these concerns, especially in low- Earth orbits. The University of California, Berkeley currently operates seven NASA spacecraft in various orbit regimes around the Earth and the Moon, and actively participates in collision avoidance operations. NASA Goddard Space Flight Center and the Jet Propulsion Laboratory provide conjunction analyses. In two cases, collision avoidance operations were executed to reduce the risks of on-orbit collisions. With one of the Earth orbiting THEMIS spacecraft, a small thrust maneuver was executed to increase the miss distance for a predicted close conjunction. For the NuSTAR observatory, an attitude maneuver was executed to minimize the cross section with respect to a particular conjunction geometry. Operations for these two events are presented as case studies. A number of experiences and lessons learned are included. Nomenclature dLong = geographic longitude increment ΔV = change in velocity dZgeo = geostationary orbit crossing distance increment i = inclination Pc = probability of collision R = geostationary radius RE = Earth radius σ = standard deviation Zgeo = geostationary orbit crossing distance I.
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