Investigation of the dust environment around Europa

Space in the vicinity of atmosphereless bodies inthe Solar system is often populated by dustoriginating from the surface. Fragments of thesurface are ejected mostly due to hypervelocitymeteoroid impacts. It is also possible that materialfrom sub-surface layers may be vented throughcracks in the ice (as detected near Enceladus).The understanding of Europa's dust cloud (anddust clouds of this sort in general) is done bymimicking micrometeoroid impact into simulatedEuropan regolith/ice using the light gas gun at theOpen University. The research is complementedwith impact modelling using the finite elementhydrocode, ANSYS Autodyn 3D. The results areimplemented in IDL in order to calculate theapproximate dust cloud population (size andspatial density) of the surface fragments atdifferent altitudes above Europa’s surface.It is, therefore, investigated whether orbit-baseddetection and analysis of material ejected from thesurface may provide an alternative method forsampling material without landing, bothquantitatively and qualitatively. Our current workis aimed at the understanding of the local dustfluxes and geometries at the orbital altitudes andits application to the design of a dust detector foran orbiter.References [1] Miljkovic, K. et al (2007) Research onEuropa's dust cloud at The Open University's HVILaboratory,26 ISTS proc. [2] Grün, E. et al. (1997) Dust measurements inthe Jovian magnetosphere, Geophys. Res. Lett., 24. [3] Holmquist, T.J. et al. (1995) High strain rateproperties and constitutive modeling of glass, 15International symposium on ballistics, 1995. [6] Melosh, H.J. (1989) Impact cratering. Ageological process, Oxford university press. [4] Divine, N. (1993), Five populations ofInterplanetary Meteoroids, JGR., 98. [5] Koschny, D and Grün, E (2001) Impacts intoIce–Silicate Mixtures: Crater morphologies,Volumes, Depth-to-Diameter Ratios, and Yield,Icarus, 154. [6] Krüger, H. et al. (2003) Impact-generated DustClouds Surrounding the Galilean Moons, Icarus,164.