A Study of Dust and Gas at Mars from Comet C/2013 A1 (Siding Spring)

TL;DR

This study models dust and gas impacts from comet C/2013 A1 near Mars, concluding impacts are unlikely to harm spacecraft but Mars may receive significant dust quantities.

Contribution

It provides a dynamical model estimating dust and gas impact fluence on Mars from comet C/2013 A1, with implications for spacecraft safety and planetary environment.

Findings

No impacts expected at Mars under nominal model.

Up to ~10^7 dust grains may reach Mars, totaling ~100 kg.

Gas molecule fluxes are also estimated.

Abstract

Although the nucleus of comet C/2013 A1 (Siding Spring) will safely pass Mars in October 2014, the dust in the coma and tail will more closely approach the planet. Using a dynamical model of comet dust, we estimate the impact fluence. Based on our nominal model no impacts are expected at Mars. Relaxing our nominal model's parameters, the fluence is no greater than ~10^-7 grains/m^2 for grain radii larger than 10 {\mu}m. Mars orbiting spacecraft are unlikely to be impacted by large dust grains, but Mars may receive as many as ~10^7 grains, or ~100 kg of total dust. We also estimate the flux of impacting gas molecules commonly observed in comet comae.