Miniature 3D Microscope and Reflectometer for Space Exploration

Abstract

Characterization of objects in all dimensions at a microscopic level is important in numerous applications including surface analysis on planetary bodies. Existing microscopes fit for this task are large bench-top devices unsuitable for in-situ use, particularly in resource-constrained remote robotic exploration. Computational imaging techniques present a powerful means to overcome physical limitations in fielded sensors, but have seen especially little use in space applications. We present a miniature (150 gram) 3D microscopic imager without moving parts capable of providing 1-megapixel images at approximately 1 micron horizontal and 5 micron vertical resolution. This device combines light-field imaging and photometric stereo to provide both 3D reconstruction and reflectance characterization of individual soil grains. We thoroughly evaluate its performance by designing and nanofabricating a 3D-fiducial and further demonstrate its operation on a library of planetary soil simulants. This system opens vast opportunities for extension, demonstrating the potential of computational imaging to amplify sensing capabilities in space.