HR: 14:15h
AN: P42B-03    [PDF]
TI: Probing the Subsurface of Mars with MARSIS on Mars Express
AU: * Plaut, J J
EM: plaut@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501 4800 Oak Grove Dr., Pasadena, CA 91109 United States
AU: Picardi, G
AF: INFO-COM Department, University of Rome "La Sapienza", Via Eudossiana, 18, Rome, 00185 Italy
AB: The Mars Express orbiter carries an instrument called the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS). The MARSIS experiment is a joint project between NASA and the Italian Space Agency. The primary objective of MARSIS is to detect, map and characterize subsurface material discontinuities in the upper portions of the crust of Mars. These may include boundaries of liquid water-bearing zones, icy layers, geologic units and geologic structures. Secondary objectives include characterization of the surface topography, roughness and reflectivity, and passive and active ionospheric sounding. Detection of water and ice reservoirs will address many key issues in the hydrologic, geologic, climatic and possible biologic evolution of Mars, including the current and past global inventory of water, mechanisms of transport and storage of water, the role of liquid water and ice in shaping the landscape of Mars, and the stability of liquid water and ice at the surface as an indication of climatic conditions. MARSIS is a multi-frequency, coherent pulse, synthetic aperture radar sounder. The instrument features flexibility in frequency selection for adaptation to the Mars environment, and a secondary, receive-only antenna and data channel to minimize the effects of surface "clutter" on subsurface feature detection. The instrument will acquire echo profiles of the subsurface of Mars at a lateral spacing of approximately 5 km and a vertical (depth) resolution of 50-100 m. Four frequency channels will be available for use: 1.8, 3.0, 4.0 and 5.0 MHz. The lower frequency channels, which are likely to penetrate more deeply, will be used during night-side operations, when the ionospheric plasma frequency is lowest. The primary antenna consists of a simple dipole with a total length of 40 m. If aquifers occur only at great depth ($>$ 5-10 km) in the martian crust, they may elude detection by MARSIS. However, shallower reservoirs of liquid water, perhaps associated with thermal anomalies or an insulating upper stratigraphy, should detectable. Many other stratigraphic and structural boundaries are expected to be identified by the radar sounding, providing a view into third dimension of the geology of Mars.
DE: 5435 Ionospheres (2459)
DE: 5464 Remote sensing
DE: 5494 Instruments and techniques
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting