Time efficient modelling of cometary dust environments to support future cometary mission planning and operations

So far all the comets that have been visited by a spacecraft were short period comets and as such their surfaces have been altered by sublimation processes. Comet Interceptor is a new F-class mission developed by the European Space Agency. The objective of the Comet Interceptor mission is to observe a dynamically new comet or an interstellar object. Comets are thought to be relicts from the formation of our solar system and as such observing a more pristine object could give new insight in the planet formation process. Comet Interceptor will be build and potentially launched before the target object has been found, because the warning times of the arrival of such objects would be too short to intercept them otherwise. For this reason the dust environment around the nucleus is difficult to constrain during the development of the mission [1].
As described in several publications ([2],[3],[4]) the dust hazard assessment will be crucial for the success of the Comet Interceptor mission. The goal of the presented work is to develop a tool that models the dust environment of a comet and can estimate the total amount of impacting particles and the total mass of the impacting particles along a chosen trajectory. We build our model to be flexible enough to enable further usage in future cometary missions. To allow for an efficient information of the user we are aiming to keep the running time of the model as low as possible, while providing an accurate estimation of the dust hazard for a wide range of scenarios. Our model is accounting for solar radiation pressure based on the scattering properties of the dust particles, emission angle dependent dust production rates and outflow velocities and variability in the dust production rate with the rotation of the nucleus. The size distribution of the particles will be treated by using logarithmic size bins and calculating the number densities of each bin. Our model will also be able to derive an Afρ value based on the scattering properties and the dust number densities, which then can be compared to ground based observations. Using a simplified case we can show, that our model is in good agreement with an analytical fountain model (see [5]). Further, we will compare our model with measurements made during the Giotto mission [6] and the engineering dust coma model [3].

Acknowledgement
This work has been carried out within the framework of the National Centre of Competence in Research PlanetS supported by the Swiss National Science Foundation. The authors acknowledge the financial support of the SNSF.

References
[1] Colin Snodgrass & Geraint H. Jones, The European Space Agency’s Comet Interceptor lies in wait. Nat Commun 10, 5418 (2019). https://doi.org/10.1038/s41467-019-13470-1
[2] Nico Haslebacher, Selina-Barbara Gerig, Nicolas Thomas, Raphael Marschall, Vladimir Zakharov \& Cecilia Tubiana, A numerical model of dust particle impacts during a cometary encounter with application to ESA’s Comet Interceptor mission, Acta Astronautica, Volume 195, 2022, Pages 243-250, ISSN 0094-5765, https://doi.org/10.1016/j.actaastro.2022.02.023.
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