LASP Science Seminars
Experimentally replicating hypervelocity ice grain sampling during a planetary flyby using laboratory impact ionization mass spectrometry
Impact ionization mass spectrometers, historically referred to as dust analyzers, have played a crucial role in planetary science mission investigations in recent decades, and will continue to do so for decades to come. Perhaps most notably, the compositional information gained from ice grains at Enceladus using the Cosmic Dust Analyzer (CDA) on board Cassini and the planned investigations within the next decade at Europa using the SUrface Dust Analyzer (SUDA) onboard Europa Clipper both illustrate the incredible science potential enabled by these instruments. However, tracing mass spectral features to ice grain composition in impact ionization mass spectrometry is non-trivial as the clustering of charged species and their relative peak areas vary as a function of both ice grain composition and encounter velocity. This is further complicated by a lack of impact ionization laboratory measurements that replicate the physics of an ice grain impact to inform the compositional measurements made by spaceborne dust detectors. Previous modeling and experimental efforts have been employed to predict or reproduce high-salt impact mass spectra collected by spaceborne dust detectors, however these studies did not involve the in-situ analysis of a true ice grain impact event. I will present and discuss hypervelocity ice grain impact mass spectra collected between 2.0 – 4.2 km/s for simple salts expected to be present at Ocean Worlds, as well as preliminary results on impact mass spectra of potential biosignature molecules, and discuss how high-fidelity laboratory measurements will be important to ensure accurate quantitative chemical information from ice grain impact mass spectra collected by Europa Clipper.
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Dr. K. Marshall Seaton is an experimental chemist that explores organic detection and evolution in Ocean World analogues. He is currently a NASA Postdoctoral Program Fellow at the Jet Propulsion Laboratory, California Institute of Technology, where he has developed and optimized an ice grain impact ionization mass spectrometry method capable of experimentally replicating an ice grain impact during a plume or exospheric Ocean World flyby in the laboratory. He is interested in how the hypervelocity impact process affects volatile formation and the ionization, molecular degradation, and detectability of various species in impact ionization mass spectrometry, and is passionate about science that can be used to inform future mission surface operations at Europa, Enceladus, and other icy worlds. In his spare time, he enjoys cooking, exercising, playing the guitar, playing videogames, and fishing.