Tony Farnham (University of Maryland, College Park, Maryland) is an astronomer who studies the dynamics of cometary nuclei and the interrelationship between a comet's nucleus and its coma. He was a member of the Science teams for the Deep Impact mission to comet Tempel 1, the extended mission (DIXI) to comet Hartley 2, and the Stardust-Next mission that returned to comet Tempel 1. He also led one of the teams that performed the analysis of the dust hazards posed by comet Siding Spring during its close approach to Mars.
Comet Siding Spring is going to make a very close approach to Mars in October. Any comet dust that reaches Mars has the potential to inflict significant damage on the spacecraft orbiting the planet. As it turns out, however, Mars and its orbiters are likely to see very few, if any, impacts. Why?