Miniaturized Scanning Electron Microscope for In Situ Planetary Studies

The exploration of remote planetary surfaces calls for the advancement of low-power, low-mass, highly-miniaturized instrumentation. Multi-functional instruments of this nature will prove to be particularly useful in preparation for human return to the moon, and in exploring increasingly remote locations in the Solar System. To this end, our group has been developing a miniaturized Scanning Electron Microscope (mSEM) capable of remote investigations of mineralogical samples through in-situ topographical and chemical analysis on a fine scale. Specifically, the fabrication and testing of a proof-of-concept assembly has begun, and consists of a cold-field-emission electron gun and custom high-voltage power supply, electrostatic electron-beam focusing column, and scanning-imaging electronics plus backscatter electron detector. The functioning of an SEM is well known: an electron beam is focused down to nanometer- scale onto a given sample resulting in emissions such as backscattered and secondary electrons, x rays, and visible light. Raster-scanning the primary electron beam across the sample results in a fine-scale image of the surface topography (texture), crystalline structure and orientation, with accompanying elemental composition. The flexibility in the types of measurements the mSEM is capable of makes it ideally suited for a variety of applications. The mSEM is appropriate for use on multiple planetary surfaces, and for a variety of mission goals (from science to non-destructive analysis to in-situ resource utilization). The current status of the development and potential mSEM applications for planetary exploration are summarized here. This effort is funded through the NASA Research Opportunities in Space and Earth Sciences - Planetary Instrument Definition and Development Program (PIDDP).