Bruce W. Rabalais (DigitalGlobe, Inc)
Keywords: debris, conjunction, collision, cola, orbit selection
Abstract:
Routine collision avoidance analyses for the DigitalGlobe imaging satellite constellation have observed periodic peaks in close approaches for WorldView-2 and the Cosmos 2251 and Iridium 33 debris populations. Investigation showed that the debris populations from previous on-orbit collision or fragmentation events tend to remain somewhat grouped in ascending nodes for sometime after the event, allowing some portions of the populations dynamics to be modeled as a group. The populations ascending nodes can be fit to a circular normal distribution, and using simple linear regression, relative motion between WorldView-2 and the debris clouds can be predicted. This modeling methodology is demonstrated using the debris populations from the former Cosmos 2251 and Iridium 33 populations, and the observed peaks in the imaging constellation operators daily conjunction notices can be shown to coincide with the satellites passage through those debris populations in a head-on fashion, as indicated by the operational satellites ascending node being 180 degrees opposite the clouds mean ascending node. The derived debris cloud model is used to demonstrate this phenomenon, matching previous peaks in DigitalGlobe constellation conjunction frequency with opposing passages through the two noted debris populations. Discussion is also provided concerning the lack of such conjunction peaks between WorldView-2 and the Fengyun-1C population.
Date of Conference: September 10-13, 2013
Track: Orbital Debris