Review on magnetic devices development for terrestrial and planetary rock characterization during field surveys

The characterization of rocks magnetic signature, via the magnetic field and its spatial gradient, and the magnetic properties of natural samples, such as the complex magnetic susceptibility, are useful tools not only to understand the composition and structure of the rock but also its geological history, with important implication on paleomagnetism and the magnetic fields involved in the early history of the planets.

The determination of this important magnetic information often requires large and complex laboratory set-ups that measure different magnetic properties and sample collection (and tools for the extraction of the rocks) on field campaigns.

Our most recent research in this discipline has been focused on the design and construction of devices that, complemented with magnetic field measurements, could enhance the in-situ magnetic characterization of rocks and soils extracted from the field campaigns and prior to laboratory characterization.

In this work we present the development of magnetic devices for a complete in-situ and non-destructive characterization of the magnetic signature and other magnetic properties of natural samples and soils, with designs compatible with rover architectures for planetary exploration. This work comprises the development of a magnetic gradiometer prototype for the complete characterization of the magnetic field, and the evolution of a magnetic susceptometer with the capability of measuring the complex magnetic susceptibility (with a sweep of frequencies between 10 and 100 kHz) in a wide range representative for natural samples. It has to be taken into account that one of the important parameters in such devices is robustness, and thus, great part of our effort has been focused to achieve high robustness devices maintaining a high maturity level (technology readiness level – TRL).