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There are a variety of complementary observations that could be used in the search for life in extraterrestrial settings. At the molecular scale, patterns in the distribution of organics could provide powerful evidence of a biotic component. In order to observe these molecular biosignatures during spaceflight missions, it is necessary to perform separation science in situ. Microchip electrophoresis (ME) is ideally suited for this task. Although this technique is readily miniaturized and numerous instruments have been developed over the last 3 decades, to date, all lack the automation capabilities needed for future missions of exploration. We have developed a portable, automated, batterypowered, and remotely operated ME instrument coupled to laserinduced fluorescence detection. This system contains all the necessary hardware and software interfaces for end-to-end functionality. Here, we report the first application of the system for amino acid analysis coupled to an extraction unit in order to demonstrate automated sample-to-data operation. The system was remotely operated aboard a rover during a simulated Mars mission in the Atacama Desert, Chile. This is the first demonstration of a fully automated ME analysis of soil samples relevant to planetary exploration. This validation is a critical milestone in the advancement of this technology for future implementation on a spaceflight mission.

For the first time, the covalent immobilization of oligonucleotides double helices onto surfaces prior to sequential denaturation and rehybridization is proven to lead to optimal hybridization efficiency. Two indirect methods were used for monitoring these reactions in situ: the quartz crystal microbalance with dissipation monitoring (QCM-D) and the wavelength interrogated optical sensor (WIOS, Bright Reader). Both techniques led to the result that with this immobilization approach one could reach nearly 100% hybridization efficiency. Moreover, applying the polymer theory to the adsorption of nucleotide sequences onto surfaces, we demonstrate, that for single stranded sequences the coil conformation prevails over the stretch one.

A top-level NASA exploration goal is the search for signs of life beyond Earth. Molecular biosignatures can be sought via in situ organic chemical analyses of samples collected from planetary bodies. Current spaceflight-ready technologies lack the required sensitivity to perform these analyses on key polar organic species primarily due to the low efficiency of transferring these molecules from natural samples into chemical instrumentation. One promising approach to improve the liberation of these molecules from sample matrices prior to analysis is through the use of liquid extraction, in which organic molecules are dissolved in heated, pressurized water. This process has never been performed on a spaceflight mission. As part of instrument maturation efforts, we describe the development of the first spaceflight prototype of a fully automated subcritical water extractor designed to provide this essential functionality on a potential future planetary mission. The prototype extractor was mounted on a Mars test rover platform and successfully operated remotely in the Atacama Desert, Chile. Samples acquired by the rover's drill and sample acquisition/delivery system were remotely transferred to the extractor inlet funnel, and all subsequent extractor operations were performed automatically. To validate the instrument and demonstrate its suitability as a front-end unit for an organic analyzer, we tested low-bioload Atacama Desert soil extracts for amino acid content using capillary electrophoresis coupled to laser-induced fluorescence. We show that hot extraction under subcritical conditions is required to liberate amino acids from the sample, as no amino acids were found in the extract produced at room temperature. Plain Language SummaryThe search for signs of life beyond Earth is one of NASA's highest priorities. One powerful way to look for extraterrestrial life is to perform chemical analyses on planetary samples in order to characterize any organic molecules present. Past and current spaceflight instruments analyze various components in gases collected or gases produced from solid samples; however, the instruments either lack the sensitivity to detect organic molecules or the instruments destroy many of the organic molecules during the preparation required to perform a gas-phase-based measurement. This work presents an automated pressurized hot water extractor that can be used to release organic molecules from a solid sample. Pressurized hot water is a powerful and easy-to-handle solvent for a wide range of different compounds. The extractor acts as a front-end instrument and prepares the sample for highly sensitive, liquid-based analysis. This automated and remotely controlled prototype has been successfully tested on a simulated Mars rover mission in the Atacama Desert in Chile. Extracts of the Atacama soil samples were then analyzed by capillary electrophoresis coupled to laser-induced fluorescence to determine the extracts' amino acid content, as amino acids are an auspicious class of molecules in the search fo...

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