The cassini f ring and proximal orbits will, for the first time, provide the opportunity to directly measure the dust component of saturns main rings. In situ dust measurements in the vicinity of…

This federal contract award, valued at $214,401.02, was granted by the National Aeronautics and Space Administration (NASA) to the Regents of the University of Colorado, doing business as the University of Colorado Office of Contracts and Grants Division. The contract is for a three-year research effort to support the Cassini spacecraft's "Grand Finale" orbits around Saturn, which will provide direct measurements of the dust component of Saturn's main rings. The research will focus on refining dust dynamics models, assimilating data from Cassini instruments to optimize observation planning, and conducting comprehensive analyses to characterize the composition, origin, and evolution of Saturn's rings, as well as their interaction with the planet's ionosphere. This award is not associated with a set-aside designation.

The cassini f ring and proximal orbits will, for the first time, provide the opportunity to directly measure the dust component of saturns main rings. In situ dust measurements in the vicinity of the rings provide observational constraints for studying the rings origin and evolution as well as how the rings interact with the host planet. The cassini cosmic dust analyser (CDA) measurements during this mission phase will focus on the dust halo engulfing the rings, which is created by sub-micron inclusions within the ICY ring particles lofted by micro-meteorite impacts and subsequently affected by electromagnetic forces. The top priority is to identify the composition of the non-ICY ring impurities based on in situ measurements. Combined with information about the electrodynamics of charged ring ejecta particles, IT is even possible to resolve the composition variation across the rings. This is the so-called ring composition mapping concept, which essentially is the dust activity associated with the ring-planet interactions. While the observation plan has been designed based on our numerical simulation results, several issues remain to be addressed to ensure the observation and the analysis to be successfully accomplished. Here we propose a three-year work plan, covering the essential elements for preparing the upcoming observations and data analysis processes before, during, and after the grand finale mission. The proposed tasks are organized according to the time frame of the grand finale orbits and cover both dust dynamics and composition aspects. Regarding dust dynamics, we will first refine our existing dust dynamics model in order to examine and eliminate the uncertainties in the current observation pointing design. In collaboration with the cassini magnetometer and radio and plasma wave science (rpws) instrument teams, we will develop procedures allowing inflight magnetic field and plasma data assimilation into our model. Incorporating these measurements during the first few orbits will provide the most realistic condition for the dynamics simulation, whose results will be used to optimize the instrument setup and pointing for the upcoming measurement opportunities. Additionally, the proposed modeling works will also contribute to the data interpretation and help to illustrate the role of dust in the ring-ionosphere interactions. Regarding the composition analysis, in order to reduce the ambiguity in mass spectra interpretation, we will first examine the temporal evolution of the CDA target contamination level using existing nanodust stream particle measurements. This information will be applied to the identification of small ejecta particles in the CDA data and also to the dust mass spectrum analysis. Based on measurements during the grand finale orbits, a comprehensive analysis combining dust dynamics and composition information will be carried out to provide constraints about the ring composition, origin and evolution, and ring-ionosphere interactions.