Mars Project Description

PI: John W. Holt Co-PI: Donald D. Blankenship
Other Professionals: Matthew J. Peters, Scott Kempf
Collaborators: C. Leuschen (Johns Hopkins University)
B. Hallet (U. of Washington), R. Sletten (U. of Washington)

Mapping water in its various forms is perhaps the most fundamental of the various Mars objectives, and the most critical in the search for signs of present or past life. Upcoming missions to Mars will employ radar sounding from orbital platforms and surface rovers in order to map subsurface ice and liquid water. The recent identification of features which exhibit morphologies consistent with ice/rock mixtures, near-surface ice bodies and near-surface liquid water point to the need for appropriate terrestrial analogs. Radar propagation models for similar features on Earth where the important physical properties can be readily determined and will be crucial for interpreting data from Mars. Climatic, hydrological, and geological conditions in the McMurdo Dry Valleys of Antarctica are analogous in many ways to those on Mars, and many ice-related features in the Dry Valleys may have direct morphologic and compositional counterparts on Mars. We propose to develop general radar models for permafrost, subsurface ice bodies, rock/ice glaciers, frozen saline lakes, and glacial deposits that occur in the Dry Valleys and that have direct relevance to future Mars missions. Observations of physical properties for these features will be assimilated into our models and the results will be compared to ~1,000 line-km of airborne radar data set that we obtained in the region. The airborne radar data were collected with multiple systems including a chirped 52.5 – 67.5 MHz coherent radar operating at 750 W and 8 kW peak power (with multiple receivers) and 1 - 2 microsecond pulse length, and a 60 MHz pulsed continuous-wave, incoherent radar operating at 8 kW peak power with 60 ns and 250 ns pulse lengths. These data are suitable for the implementation of advanced pulse compression algorithms and SAR focusing. Our model comparisons with these data will use different radar configurations and parallel tracks where they are available. Self-consistent models will indicate valid analogs. In any cases where fundamental ambiguities cannot be resolved, we will define specific additional measurements or radar experiments that would be required to construct more complete models. We will work closely with collaborators to ensure that all relevant physical observations of Dry Valleys features and processes are included, that suitable data processing algorithms are developed, and that our terrestrial radar analogs are applicable to specific future Mars missions.