Deriving Impact Ejecta Launch Site Distributions for Mapping the Composition of Europa
Abstract
The Surface Dust Analyzer (SUDA) is a time-of-flight mass spectrometer that will fly aboard NASA's Europa Clipper with an expected launch date in 2023. During close flybys of Europa (~25-100 km at closest approach), SUDA will measure the the chemical composition of particles encountered by the instrument via impact ionization. SUDA is expected to collect particles from both ice particle plumes on the surface of Europa and surface ejecta created by hypervelocity impacts of micrometeoroids with the moon. The focus of this study is on associating detected surface ejecta with their site of origin on Europa. This is achieved with probability distributions derived using Monte Carlo simulations. The simulations are designed using established models of impact ejecta dynamics and include the necessary distributions of particle velocities for a given position relative to Europa. The simulated velocities and detection positions are used to backtrack the ejecta particle's trajectory to its launch site on the surface, providing distinct launch site distributions with respect to the sub-spacecraft point.
The spatial resolution of surface chemical composition measurements along the ground track of the spacecraft can be characterized for any flyby. We also show how measuring the grain entry velocity parallel to the boresight of the instrument with a 1% uncertainty further constrains the probable launch site area thereby improving the resolution of compositional mapping performed by SUDA. This method plays a key role in the science planning for the instrument and will enhance the analysis of returned data from Europa Clipper's mission.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P53D3480G
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHERE;
- 6207 Comparative planetology;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6221 Europa;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6282 Enceladus;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS