Science Applications of a Multispectral Microscopic Imager for the Astrobiological Exploration of Mars

Abstract

Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples most likely to harbor fossil biosignatures. The Multispectral Microscopic Imager (MMI) provides multispectral reflectance images of geological samples at the microscale, where each image pixel is composed of a visible/shortwave infrared spectrum ranging from 0.46 to 1.73 lm. This spectral range enables the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases, and the detection of hydrated minerals. The MMI advances beyond the capabilities of current microimagers on Mars by extending the spectral range into the infrared and increasing the number of spectral bands. The design employs multispectral light-emitting diodes and an uncooled indium gallium arsenide focal plane array to achieve a very low mass and high reliability. To better understand and demonstrate the capabilities of the MMI for future surface missions to Mars, we analyzed samples from Mars-relevant analog environments with the MMI. Results indicate that the MMI images faithfully resolve the fine-scale microtextural features of samples and provide important information to help constrain mineral composition. The use of spectral endmember mapping reveals the distribution of Fe-bearing minerals (including silicates and oxides) with high fidelity, along with the presence of hydrated minerals. MMI-based petrogenetic interpretations compare favorably with laboratory-based analyses, revealing the value of the MMI for future in situ rover-mediated astrobiological exploration of Mars.

Microbial Morphology and Motility as Biosignatures for Outer Planet Missions

“…It has since been coupled with a laser ablation mass spectrometer to produce a multimodal instrument called CAMAM (Tulej et al , 2014 ). Other types of instruments with similar spatial resolution have also been proposed, some spanning several orders of spatial resolution, from centimeters to millimeters (Fink et al , 2013 ; Nunez et al , 2014 ). While this type of spatial resolution is ideal for mineralogy and perhaps fossilized microbial biosignatures (Hofmann, 2008 ; Pullan et al , 2008 ), it is insufficient for observation of living microorganisms and not at all intended for time-lapse imaging of motile specimens.…”

The Development and Demonstration of the Portable Acousto‐Optic Spectrometer for Astrobiology in Cave Environments

“…Broadly speaking, a wide range of both passive and active in situ techniques have been developed for and employed in the characterization of planetary surface environments in an effort to identify potential biomarkers. These techniques include (but are not limited to) mass spectrometry (Garcia‐Descalzo et al., 2012 ; Getty et al., 2012 ), Raman spectroscopy (Tarcea et al., 2007 ), X‐ray diffraction spectroscopy (Blake et al., 2012 ), imaging microscopy (Núñez et al., 2014 ), and laser induced breakdown spectroscopy (LIBS) (Pavlov et al., 2012 ; Schröder et al., 2013 ). There is general agreement that a multitude of techniques probing a range of spatial and temporal scales is needed to determine the presence of extant or extinct life on another planetary body (Boston et al., 2001 ; Cady et al., 2003 ; Conrad & Nealson, 2001 ; Wynne et al., 2022 ).…”

Comparison of Image Endmember- and Object-Based Classification of Very-High-Spatial-Resolution Unmanned Aircraft System (UAS) Narrow-Band Images for Mapping Riparian Forests and Other Land Covers

“…Wang and Chang [42] conducted endmember-based classification of high-spatial-resolution HSI. Núñez et al [43] performed image endmember-based mapping using multispectral images of geological samples at the microscale. Gong et al [44] estimated rapeseed yield with unmanned aerial vehicle (UAV)-based spectra and abundance data by spectral mixture analysis.…”