Wideband In-Situ Electromagnetic Sensor for Exploring Planetary Subsurface

We propose a new broadband electromagnetic (EM) sensor, called GEM-5 (Figure 1), to measure the electrical conductivity of the first 5-10 m of Martian in-situ geology. The depth of exploration may increase with a higher transmitter power. While the sensor can be used for exploring other planets and moons, this proposal is directed specifically to a small rover such as the 1997 Sojourner to Mars. The proposed sensor will weigh less than 500 g, and its overall power consumption would be insignificant owing to its low duty cycle, assuming a slow rover speed. The GEM-5 sensing element is new and will be designed to be operated on a small rover. The proposed GEM-5 is designed to be a vertical EM gradiometer. The innovative antenna design calls for a very compact packaging and high spatial resolution for conductivity mapping. To lower the development cost and engineering risk, however, the data processing console will be largely based on its predecessors, GEM-2 and GEM-3, which have been highly successful for commercial geophysical surveys.Referring to desired technologies listed under this NASA SBIR topic: Instruments for Conducting In Situ Scientific Measurements, the proposed sensor can contribute to:¿ In situ characterization of planetary subsurface regions¿ Subsurface mineralogical compositions of soils, ices, sedimentary rocks, and minerals;¿ Geological and environmental understanding, and;¿ Electromagnetic and magnetic properties of shallow subsurface.The sensor will have the following specifications suitable for a rover deployment:¿ Light (<500 gm), robust, and easy to deploy;¿ Multifrequency data -- to determine layered structures such as permafrost and ice layers;¿ Low data rate due to intermittent operation for a slow-moving rover; and¿ Low power consumption (<1 watt-hour).