P11C-2110
Surface Reflectometry and Ionosphere Sounding from the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON)

Monday, 14 December 2015
Poster Hall (Moscone South)
Cyril Grima1, Donald D Blankenship2, Dustin M Schroeder3, Alina Moussessian4, Krista M Soderlund2, Yonggyu Gim3, Jeffrey J Plaut5, Jamin Stevens Greenbaum1, Erika Lopez Garcia1, Bruce A Campbell6, Nathaniel Edward Putzig7 and Gerald Patterson8, (1)University of Texas, Institute for Geophysics, Austin, TX, United States, (2)Institute for Geophysics, Austin, TX, United States, (3)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (4)Jet Propulsion Laboratory, Pasadena, CA, United States, (5)JPL, Pasadena, CA, United States, (6)Smithsonian National Air and Space Museum, Washington, DC, United States, (7)Southwest Research Institute Boulder, Boulder, CO, United States, (8)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States
Abstract:
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) has been selected for the scientific payload of a NASA's multiple flyby mission to explore the icy moon Europa. REASON is an active dual-frequency (9/60 MHz) instrument led by the University of Texas Institute for Geophysics (UTIG). It is designed to achieve multi-disciplinary measurements to investigate subsurface waters and the ice shell structure (Sounding), the surface elevation and tides (Altimetry), the surface physical properties (Reflectometry), and the ionospheric environment (Plasma/Particles). We will present the concepts behind the “Reflectometry” and “Plasma/Particles” measurements, demonstrate their efficiency with planetary analogs, and anticipate their capabilities for the exploration of Europa. We will also highlight the potential synergies with other instruments selected for the Europa mission payload.

The “Reflectometry” compares the statistical behavior of the surface echo amplitudes with theoretical stochastic models to separate the reflected and scattered contributions to the signal. Once those two components are deduced they are used in a backscattering model to invert surface properties such as roughness, density, and/or impurity load. “Reflectometry” measurements will contribute to the statistical characterization of the surface over ~ 10-km-long areas with a ~ 10 m skin depth for geological investigation, near-surface brine detection, plume-deposited snow characterization, and landing site reconnaissance. The “Plasma/Particles” measurement relies on the dispersive signal delays induced by the ionospheric content integrated along the radio propagation path. Correction of this delay with existing techniques provides the total electron content below the spacecraft. “Plasma/Particles” measurements will constrain the ionosphere’s shape and variability along the acquisition track and might detect transient plume-induced ionosphere when active.

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