Initial Analysis of Iridium 33-Cosmos 2251 Collision

T.S. Kelso

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Overview

• Background• Collision Geometry• Tracking a Collision• Debris Cloud Evolution• Summary & Conclusions

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Background

• On 2009 February 10 at 1656 UTC, Iridium 33 went silent

• SOCRATES report from 1502 UTC reported a 584-m close approach at that time with Cosmos 2251

• JSpOC confirmed tracking of debris in both orbits

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• Fresh TLEs (1.207 & 1.340 DSE)

• TCA 16:55:59.806 UTC

• Min range: 584 m

• Relative velocity 11.647 km/s

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Collision Geometry

• Views– Just prior to collision– Collision plus 10 minutes with debris– Collision plus 180 minutes with debris

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Tracking a Collision

• At time of collision, conjunction ranked:– 152 overall– 15 of all Iridium– 2 for Iridium 33

• Number of conjunctions at time of collision:– 11 for Iridium 33– 1,019 for Iridium– 11,428 for all 2,946 objects (against 11,842)

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Tracking a Collision

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Tracking a Collision

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Tracking a Collision

Debris Cloud Evolution

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Debris Cloud Evolution

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Debris Cloud Evolution

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Summary & Conclusions

• First known collision between two satellites• Screening is difficult without better data

– Technical issues regarding cost and difficulty are not the problem

• Debris problem in LEO rapidly worsening• We must work together now to mitigate risks

Questions?

http://celestrak.com/events/collision.asp