Mars Exploration Using ELF Electromagnetic Measurements

Abstract:

We present a methodology and instrumentation allowing for an investigation of the major environmental aspects of Mars, such as the structure of the planetary subsurface, and the presence of electrical discharges in the atmosphere.

The methodology is based on the propagation of extremely low frequency (ELF) electromagnetic (EM) waves (3Hz-3kHz). These weakly attenuated waves, once generated by electrical discharges, propagate around a planet in a waveguide made of two electrically conductive spheres: the ground and the ionosphere. They are also capable of producing global EM resonances called Schumann resonances (SR).

When an ELF wave is propagating from its source to a receiver, the environmental properties, such as: electrical conductivity of the waveguide boundaries, influence its propagation parameters. Using an analytical approach, we can estimate the structure of the planetary subsurface or the lower ionosphere layers on the basis of the measured parameters.

As there is no liquid water at the Martian surface, the Martian low-conductivity ground enables deep ELF penetration into the planetary subsurface. As a result, the presented technique can be used as a tool to detect groundwater reservoirs located even several kilometers below the surface.

On the basis of presently available date on the Martian subsurface, and theories of electrical properties of rocks, ice and water, we have developed probable Martian subsurface models with and without aquifers. The obtained results indicate that if aquifers are present beneath the Martian surface, the SR frequencies, the SR amplitudes, and the ELF phase velocities will be higher by about 12%, 37%, and 9%, respectively, as compare to the situation, in which there is solely a dry basaltic ground.

As the presented phenomenon is of the global nature, one measuring station, located at the planetary surface, is enough to perform some basic research. The proposed lightweight measuring equipment, consisting of a low-power ELF receiver, and antennas, allows a one-year investigation.

Acknowledgements. This work has been supported by the National Science Centre grant 2012/04/M/ST10/00565 and 2013/09/N/ST9/02200.