Magnetic Investigations of the Martian Subsurface

Magnetic observations at Mars are vital for several important areas, including its magnetosphere, ionosphere, atmosphere, crust, and subsurface. Focusing specifically on the subsurface, there numerous ways that magnetic observations can be used to probe the subsurface and its structure, including layering, aquifers, and caves. A variety of science targets lie in the subsurface including the global/regional/local stratigraphy, mineral concentrations, potential aquifers, and potential void spaces (e.g. caves). E&M sounding is a technique used on Earth for such work; doing this at Mars is an obvious step as we increasingly send more assets to the surface. Low resource mission scenarios include 1) small, deployable packages that could make the necessary multi-point measurements or 2) instruments on mobile assets (robotic rovers/flyers, driven vehicles, or even astronauts) that could conduct surveys. There are several types of magnetometers that could be used depending the exact goals and mission scenario, but all magnetometers are relatively low resource instruments. In all cases, some techniques would use only low-frequency magnetometers (i.e. fluxgates) alone. Other techniques would combine active source elements or other instruments (e.g. electrometers). I will review these possible science targets and mission scenarios.