T.S. Kelso, Center for Space Standards and Innovation
Keywords: Iridium, Cosmos Collision
Abstract:
On 2009 February 10, Iridium 33–an operational US communications satellite in low-Earth orbit–was struck and destroyed by Cosmos 2251–a long-defunct Russian communications satellite. This is the first time since the dawn of the Space Age that two satellites have collided in orbit.
To better understand the circumstances of this event and the ramifications for avoiding similar events in the future, this paper provides a detailed analysis of the predictions leading up to the collision, using various data sources, and looks in detail at the collision, the evolution of the debris clouds, and the long-term implications for satellite operations.
The only publicly available system available to satellite operators for screening for close approaches, SOCRATES, did predict this close approach, but it certainly wasn’t the closest approach predicted for the week of February 10. In fact, at the time of the collision, SOCRATES ranked this close approach 152 of the 11,428 within 5 km of any payload. A detailed breakdown is provided to help understand the limitations of screening for close approaches using the two-line orbital element sets. Information is also provided specifically for the Iridium constellation to provide an understanding of how these limitations affect decision making for satellite operators. Post-event analysis using high-accuracy orbital data sources will be presented to show how that information might have been used to prevent this collision, had it been available and used.
Analysis of the collision event, along with the distribution of the debris relative to the original orbits, will be presented to help develop an understanding of the geometry of the collision and the near-term evolution of the resulting debris clouds. Additional analysis will be presented to show the long-term evolution of the debris clouds, including orbital lifetimes, and estimate the increased risk for operations conducted by Iridium and other satellite operators in the low-Earth orbit environment.
The final portion of the paper will look at how collaborative efforts, such as the current Data Center operations supporting SOCRATES-GEO, might be used to reduce the overall risk of similar events in the future.
Date of Conference: September 1-4. 2009
Track: Iridium/Cosmos Collision