In this work we propose to examine in situ plume measurements by the cassini plasma spectrometer (caps), cosmic dust analyser (CDA), and langmuir probe (LP, a subsystem of the radio and plasma wave…

The Regents of the University of Colorado has been awarded a $452,534 grant by a civilian federal agency (Shared Services Center) to conduct research examining in situ plume measurements from the Cassini spacecraft's instruments during flybys of Enceladus, Saturn's icy moon. The research leverages data from the Cassini Plasma Spectrometer (CAPS), Cosmic Dust Analyser (CDA), and Langmuir Probe to characterize plasma generated by intense dust impacts within Enceladus's water plume. By quantifying the relationship between impact plasma and dust mass density, the research team will derive plume dust profiles independent of grain size distribution and develop an ad-hoc plume dust model. The work is scheduled for completion by February 9, 2027, with performance occurring at the University of Colorado's Boulder, Colorado campus.

The research addresses two primary science questions regarding plume variability over Enceladus's orbital cycle: whether observed brightening at orbital apocentre results from increased dust production or altered size distribution, and how plume ice grains influence plume-magnetosphere interactions. This grant supports fundamental planetary science research contributing to a deeper understanding of Enceladus's geophysical processes and subsurface ocean interactions. The award carries no set-aside designation, reflecting the university's competitive standing in federal research funding. As a premier research institution with extensive experience managing NASA science missions and multi-agency research portfolios, the University of Colorado brings substantial expertise in space science data analysis and planetary research to this investigation.

In this work we propose to examine in situ plume measurements by the cassini plasma spectrometer (caps), cosmic dust analyser (CDA), and langmuir probe (LP, a subsystem of the radio and plasma wave science instrument). Our preliminary results show that plasma generated from intense dust impacts in the plume contributes significantly to data collected by caps and LP. Since the amount of dust impact plasma is directly proportional to dust mass density, characterization of the impact plasma detected within the plume allows US to derive plume dust mass density profiles independent of the dust size distribution. Our first proposed tasks are to quantify the impact plasma process caused by plume ICE grains using multiple in situ dataset. Applying characterized impact plasma parameters to analyze in situ dataset from various plume crossing flybys, we will evaluate the plume dust variation over enceladus orbit and address the following science questions: (1) does the brightening of enceladus plume near its orbital apocentre cause by increasing dust production and/or changing dust size distribution? (2) what are the effects of plume ICY grains regarding plume-magnetosphere interactions? We also plan to develop an ad-hoc plume dust model.