Investigations of Mercury’s Ice-bearing Polar Craters
National Aeronautics and Space Administration Discovery Data Analysis Program
Subaward to PSI from The Johns Hopkins University Applied Physics Laboratory
PI: Nancy Chabot (The Johns Hopkins University Applied Physics Laboratory)
PSI Personnel
Project Description
The proposed work will use data in the PDS archive from the MESSENGER mission to investigate Mercury's polar deposits. In particular, raw data from the Mercury Dual Imaging System (MDIS) and Mercury Laser Altimeter (MLA) instruments, as well as MESSENGER advanced digital elevation model (DEM) and global mosaic products, will be used to produce new DEMs to model the illumination and thermal conditions of the deposits with comparisons to mapping and analysis of the visible images of the deposits. The outstanding science question that motivates the proposed work is: What is the source and evolution of the water ice and other volatiles in Mercury's polar deposits? Four independent tasks willl be undertaken to address that fundamental question: (1) Investigate polar deposits with low-reflectance surfaces; (2); Investigate polar deposits with surface ice; (3) Investigate the lowest-latitude craters that host radar-bright deposits; and (4) Investigate the thermal environment of Mercury's south polar deposits. The results will be used to provide constraints on the distribution of Mercury's water ice deposits, the properties of the low-reflectance materials that cover the water ice in many locations, and the boundaries of the deposits, which any hypothesis for the source and evolution of Mercury's water ice must meet.
As a Discovery Data Analysis Program (DDAP) Co-Investigator, Dr. Matthew Siegler will contribute to the objectives of the proposed work to use data from NASA’s MESSENGER mission to investigate the deposits of water ice and other volatile materials present in the permanently shadowed regions near Mercury’s poles. Earth- based radar observations and data from the MESSENGER mission have provided strong evidence that water ice and other volatiles are present in permanently shadowed regions near Mercury’s poles. However, there are a number of open scientific questions about these deposits, including the origin of the water and other volatiles, the extent of the deposits, the age of the deposits, and the evolution of these materials to the present day. The goals and objectives of the proposed work are focused on advancing the information available about the characteristics of these deposits, such as their reflectance, morphologic, and topographic properties, illumination conditions, and thermal environments. The new information gained about these properties and conditions would provide new implications for the origin and evolution of water ice on Mercury. All data from the MESSENGER mission to be used in the proposed work are publically available and archived in the PDS.
Dr. Siegler would lead the efforts to produce new thermal models for local regions of high scientific interest at Mercury’s poles, utilizing Digital Elevation Models (DEM) derived from data from MESSENGER’s Mercury Laser Altimeter (MLA). Dr. Siegler would also use these thermal model products to model the depth that water ice and other volatiles would be stable in these regions near Mercury’s poles. These products would contribute to the full investigation proposed of Mercury’s polar deposits, as others on the proposal would lead efforts to develop topographic and illumination models and analyze MESSENGER images. Dr. Siegler would contribute to the overall discussion of the combined results, the determination of the implications for the source and evolution of water ice on Mercury, and the presentation and publication of the results.