Applications of Surface Penetrating Radar for Mars Exploration

Abstract:

Surface Penetrating Radar (SPR) is a geophysical method that uses electromagnetic field probe the interior structure and lithological variations of a lossy dielectric materials, it performs quite well in dry, icy and shallow-soil environments. The first radar sounding of the subsurface of planet was carried out by Apollo Lunar Sounder Experiment (ALSE) of the Apollo 17 in 1972. ALSE provided very precise information about the moon's topography and revealed structures beneath the surface in both Mare Crisium and Mare Serenitatis.

Russian Mars'92 was the first Mars exploration mission that tried to use SPR to explore martian surface, subsurface and ionosphere. Although Mars'96 launch failed in 1996, Russia(Mars'98, cancelled in 1998; Phobos-Grunt, launch failed in 2011), ESA(Mars Express, succeeded in 2003; Netlander, cancelled in 2003; ExoMars 2018) and NASA(MRO, succeeded in 2005; MARS 2020) have been making great effects to send SPR to Mars, trying to search for the existence of groundwater and life in the past 20 years. So far, no Ground Penetrating Radar(GPR) has yet provided in situ observations on the surface of Mars. In December 2013, China's CE-3 lunar rover (Yuto) equipped with a GPR made the first direct measurement of the structure and depth of the lunar soil, and investigation of the lunar crust structure along the rover path. China's Mars Exploration Program also plans to carry the orbiting radar sounder and rover GPR to characterize the nature of subsurface water or ices and the layered structure of shallow subsurface of Mars.

SPR can provide diversity of applications for Mars exploration , that are:

• to map the distribution of solid and liquid water in the upper portions of the Mars’ crust;
• to characterize the subsurface geologic environment;
• to investigate the planet’s subsurface to better understand the evolution and habitability of Mars;
• to perform the martain ionosphere sounding.

Based on SPR's history and achievements, combined with the development of radar technology, SPR's technological trends applied in moon and deep space exploration are summarized in the following:

• Technological convergence in SPR and SAR(Synthetic Aperture Radar);
• Muliti-frequency and Multi-polarization;
• Bistatic or multistatic SPRs for geophysical network;
• Tomography.