A combination of radar and thermal approaches to search for methane clathrate in the Martian subsurface
It has been suggested that methane clathrate is stable in the subsurface of Mars (Max and Clifford, (J. Geophys. Res.-Planets 105 (E2) (2000) 4165). Max and Clifford (Geophys. Res. Lett. 28(9) (2001) 1787) have proposed that the Martian chaotic terrain could be a surface manifestation of the dissociation of subsurface methane clathrate hydrate. They have used the large terrestrial sub-oceanic landforms (which have formed due to dissociation of methane clathrate) as an analog. The detection of methane (either in the form of gas or in the solid form of clathrate hydrate) would be evidence of indigenous life in the Martian subsurface, since methane on Earth has mostly biogenic origin. Moreover, methane is a valuable resource for the human exploration of Mars. We propose a novel approach to search for potential Martian methane clathrate hydrate and perform related computations. Our method uses the effect of latent heat of clathrate-phase transitions on the internal heat flow, and hence on permafrost thickness above the clathrate deposit. It will allow one to extract related information out of the radar data that will be used to search for the ground ice/ground water interface. The interpretation of the radar data of ground ice/ground water boundary, which we propose here, can be used to analyze the SHARAD radar data set (Seu et al., 2003) on the Mars Reconnaissance Orbiter (MRO) 2005 mission and the potential Ground Penetrating Radar data on the Mars Science Laboratory, currently planned to be launched in 2009. From this viewpoint we make recommendations for future orbiting/landed missions to Mars.