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One excellent biosignature for the present detection of microbial life on Earth is motility, leading to its growing interest within the astrobiological community as an observable attribute that, if detected during future in situ space missions, could point towards the existence of life on Mars or other celestial bodies. Microbial motility can be induced by various stimulants, including certain chemicals called chemoeffectors, leading to subsequent chemotaxis. Following this concept, this work examines the chemotactic affinities of the bacteria Bacillus subtilis and Pseudoalteromonas haloplanktis as well as the archaeon Haloferax volcanii for L-serine, which has been previously demonstrated to have a high chemoeffective potency across a wide range of species from all domains of life on Earth. Methodologically, we introduce here a novel approach for utilizing µ-slides that diverges from the more traditional long-term chemotactic assay in favor of a shorter time frame assay that only requires a simple blob detection algorithm for microbial detection. Given the technical, computational, and time constraints necessary for an in-situ life detection mission, this simplified approach could be a cost and resource-effective way to probe for potential chemotactic-responsive life. Overall, the results indicated that each of the three organisms showed chemotactic behavior toward L-serine, which, to our knowledge, is the first time that an L-serine-induced chemotactic response has been detected for H. volcanii. [ABSTRACT FROM AUTHOR]

Abstract The study of whether life exists, is extinct, or not depends on various sophisticated experimental studies, as many different signatures of life can be used. The experimental procedures that can be performed to identify life can be further restricted by time, resources, and mobility constraints. Therefore, any research analyzing the presence of extraterrestrial life must be precise and unambiguous. This research focuses on the objective of the extraterrestrial life detection domain and seeks to provide an efficient protocol that can produce life detection decisions based on empirical data obtained through chemical analysis under time and resource-constrained conditions. While the majority of existing frameworks in this field are designed to identify biomolecules, our goal is to accomplish the same with minimal operational expense and mission complexity. We argue that the thoughtful integration of multiple biomolecular detections with lesser complexity and a robust framework can improve overall mission performance by satisfying the necessary time and resource constraints. In this study, a rapid multiple biomolecules-based life detection protocol (MBLDP-R) from soil samples is developed from scratch and embedded in an operational scientific rover subsystem targeted for planetary analysis missions. The study uses artificial biomolecule samples and simulated extraterrestrial environments to illustrate the suggested protocol’s end-to-end process. First, we list a few significant biomolecules, including lipids, proteins, carbohydrates, nucleic acids, ammonia, and pigments. Then, a weighted qualitative test scoring is applied to sort out the best test method for the finally selected biomolecules which are used as operational analogue to showcase the protocol’s in-situ analysis and decision-making capabilities. Based on the suitable biomolecules, a scientific exploration subsystem is developed, and the implemented protocol is built to perform onboard sample analysis. Evaluation results show that: (1) the proposed MBLDP-R protocol could effectively predict the classes with an average f1-score of 98.65% (macro) and 90.00% (micro), (2) the area under the Receiver Operating Characteristics (AUC-ROC) curve shows the sample categories to be correctly predicted 92% of the time (97% for Extant, 88% for Extinct, and 92% in the case of NPL), and (3) the protocol is time-efficient with an average completion time of 17.60 min, demonstrating the protocol’s rapid nature in detecting biosignatures in soil samples. The research outcome yields useful additional data for related future studies, particularly in the design of scientific frameworks for mission-specific requirements with limited resources while also serving as a reference point for constraint evaluation methods for similar systems.

In response to the problem of blocked escape routes and difficulty in determining the location of trapped personnel caused by mining disasters and accidents, based on the principles and characteristics of ultra wideband (UWB) radar life information detection and position detection, combined with existing UWB radar detection technology, a UWB radar architecture suitable for borehole detection is proposed, key technical parameters are clarified, and a UWB radar life information detector is developed; we conducted UWB radar detection experiments under different detection distances, positions, target numbers, and weak body movements, and obtained detection spectrum features under three conditions. The experimental results show that the UWB radar life information detector can penetrate a 0.5 m brick wall and accurately locate personnel spatial information in complex terrain after disaster deformation. It can observe small-scale movements of personnel within a range of 4.0 m from radar echoes; when multiple human targets are within the same range of the radar transmitting and receiving antennas, and there are differences in their radial relative positions from the radar, the number of human targets can be determined based on the echo spectrum.

This study investigates the effects of three Martian-relevant salts—sodium chlorate, sodium perchlorate, and sodium chloride—on the viability and motility of Escherichia coli, a model organism for understanding microbial responses to environmental stress. These salts are abundant on Mars and play a crucial role in forming brines, one of the few sources of stable liquid water on the planet. We analyze the survivability under different salt concentrations using colony plating. Additionally, we perform a semi-automated motility analysis, analyzing microbial speeds and motility patterns. Our results show that sodium perchlorate is the most toxic, followed by sodium chlorate, with sodium chloride being the least harmful. Both survivability and motility are affected by salt concentration and exposure time. Notably, we observe a short-lived increase in motility at certain concentrations, particularly under sodium chlorate and sodium perchlorate stress, despite rapid declines in cell viability, suggesting a stress response mechanism. Given that motility might enhance an organism's ability to navigate harsh and variable environments, it holds promise as a key biosignature in the search for life on Mars. [ABSTRACT FROM AUTHOR]

In the solar system, Icy Worlds such as Europa and Enceladus hold great potential for extraterrestrial life and may provide humanity an answer, within this century, to the age-old question of life beyond Earth. Exo-AUV technology shows promise in life detection in the icy shell, at the ice-water interface and on the seafloor of exo-ocean. Space agencies, including NASA and DLR, are enthusiastic about deploying Exo-AUVs to explore life in these regions. However, the where and how to find life, the technologies to be utilized and the goals to be achieved are crucial aspects for future Exo-AUV life detection missions on Icy Worlds. This study delves into a hypothetical mission of life detection on Europa, discussing science goals, detectable objects, potential regions and biogenic analysis for Icy Worlds. It proposes a life detection strategy for Icy Worlds based on Exo-AUVs, presents key contextual elements for Exo-AUV operations, outlines technological requirements for hull, payloads and autonomy, introduces the current state of Exo-AUV research and addresses existing challenges. This study also suggests a roadmap for conceptual development of Exo-AUV and a Concept of Operations for Multiple Exo-AUV System (ConOps for MEAS). This system aims to assist planetary scientists and astrobiologists in exploring Icy Worlds, identifying robust biosignatures and potentially discovering extant organisms, even prebiotic chemical systems. [ABSTRACT FROM AUTHOR]

The study of whether life exists, is extinct, or not depends on various sophisticated experimental studies, as many different signatures of life can be used. The experimental procedures that can be performed to identify life can be further restricted by time, resources, and mobility constraints. Therefore, any research analyzing the presence of extraterrestrial life must be precise and unambiguous. This research focuses on the objective of the extraterrestrial life detection domain and seeks to provide an efficient protocol that can produce life detection decisions based on empirical data obtained through chemical analysis under time and resource-constrained conditions. While the majority of existing frameworks in this field are designed to identify biomolecules, our goal is to accomplish the same with minimal operational expense and mission complexity. We argue that the thoughtful integration of multiple biomolecular detections with lesser complexity and a robust framework can improve overall mission performance by satisfying the necessary time and resource constraints. In this study, a rapid multiple biomolecules-based life detection protocol (MBLDP-R) from soil samples is developed from scratch and embedded in an operational scientific rover subsystem targeted for planetary analysis missions. The study uses artificial biomolecule samples and simulated extraterrestrial environments to illustrate the suggested protocol's end-to-end process. First, we list a few significant biomolecules, including lipids, proteins, carbohydrates, nucleic acids, ammonia, and pigments. Then, a weighted qualitative test scoring is applied to sort out the best test method for the finally selected biomolecules which are used as operational analogue to showcase the protocol's in-situ analysis and decision-making capabilities. Based on the suitable biomolecules, a scientific exploration subsystem is developed, and the implemented protocol is built to perform onboard sample analysis. Evaluation results show that: (1) the proposed MBLDP-R protocol could effectively predict the classes with an average f1-score of 98.65% (macro) and 90.00% (micro), (2) the area under the Receiver Operating Characteristics (AUC-ROC) curve shows the sample categories to be correctly predicted 92% of the time (97% for Extant, 88% for Extinct, and 92% in the case of NPL), and (3) the protocol is time-efficient with an average completion time of 17.60 min, demonstrating the protocol's rapid nature in detecting biosignatures in soil samples. The research outcome yields useful additional data for related future studies, particularly in the design of scientific frameworks for mission-specific requirements with limited resources while also serving as a reference point for constraint evaluation methods for similar systems. [ABSTRACT FROM AUTHOR]

Recent advances in subsurface microbiology have demonstrated the habitability of multi-million-year-old igneous rocks, despite the scarce energy supply from rock-water interactions. Given the minimal evolution coupled with exceedingly slow metabolic rates in subsurface ecosystems, spatiotemporally stable igneous rocks can sustain microbes over geological time scales. This study investigated a 2-billion-year-old mafic rock in the Bushveld Igneous Complex, South Africa, where ultradeep drilling is being executed by the International Continental Scientific Drilling Program (ICDP). New procedures were successfully developed to simultaneously detect indigenous and contaminant microbial cells in a drill core sample. Precision rock sectioning coupled with infrared, fluorescence, and electron microscopy imaging of the rock section with submicron resolution revealed microbial colonization in veins filled with clay minerals. The entry and exit of microbial cells in the veins are severely limited by tight packing with clay minerals, the formation of which supplies energy sources for long-term habitability. Further microbiological characterization of drilled rock cores from the Bushveld Igneous Complex will expand the understanding of microbial evolution in deep igneous rocks over 2 billion years. [ABSTRACT FROM AUTHOR]

Low-molecular-mass organic chemicals are widely discussed as potential indicators of life in extraterrestrial habitats. However, demarcation lines between biotic chemicals and abiotic chemicals have been difficult to define. Here, we have analyzed the potential utility of the quantum chemical property, HOMO-LUMO gap (HLG), as a novel proxy variable of life, since a significant trend towards incrementally smaller HLGs has been described in the genetically encoded amino acids. The HLG is a zeroth-order predictor of chemical reactivity. Comparing a set of 134 abiotic organic molecules recovered from meteorites, with 570 microbial and plant secondary metabolites thought to be exclusively biotic, we found that the average HLG of biotic molecules was significantly narrower (−10.4 ± 0.9 eV versus −12.4 ± 1.6 eV), with an effect size of g = 1.87. Limitation to hydrophilic molecules (XlogP < 2) improved the separation of biotic from abiotic compounds (g = 2.52). The "hydrophilic reactivity" quadrant defined by |HLG| < 11.25 eV and XlogP < 2 was populated exclusively by 183 biotic compounds and 6 abiotic compounds, 5 of which were nucleobases. We conclude that hydrophilic molecules with small HLGs represent valuable indicators of biotic activity, and we discuss the evolutionary plausibility of this inference. [ABSTRACT FROM AUTHOR]

Abstract Detecting life has driven research and exploration for centuries, but recent attempts to compile and generate a framework that summarizes life features, aimed to develop strategies for life detection missions beyond planet Earth, have disregarded a key life feature: behavior. Yet, some behaviors such as biomineralization or motility have occasionally been proposed as biosignatures to detect life. Here, we capitalize on a specific taxis’ motility behavior, magnetotaxis, to experimentally provide insights in support of behavior as an unambiguous, sensitive biosignature, and magnetic forces as a prescreening option. Using a magnetotactic bacterial species, Magnetospirillum magneticum, we conducted a lab sensitivity experiment comparing PCR with the hanging drop behavioral assay, using a dilution series. The hanging drop behavioral assay visually shows the motility of MTB toward magnetic poles. Our findings reveal that the behavioral assay exhibits higher sensitivity in the detection of M. magneticum when compared to the established PCR protocol. While both methods present similar detection sensitivities at high concentrations, at ≥ 10–7 fold dilutions, the behavioral method proved more sensitive. The behavioral method can detect bacteria even when samples are diluted at 10–9. Comparable results were obtained with environmental samples from the Hula Valley. We propose behavioral cues as valuable biosignatures in the ongoing efforts of life detection in unexplored aquatic habitats on Earth and to stimulate and support discussions about how to detect extant life beyond Earth. Generic and robust behavioral assays can represent a methodological revolution.

Detecting life has driven research and exploration for centuries, but recent attempts to compile and generate a framework that summarizes life features, aimed to develop strategies for life detection missions beyond planet Earth, have disregarded a key life feature: behavior. Yet, some behaviors such as biomineralization or motility have occasionally been proposed as biosignatures to detect life. Here, we capitalize on a specific taxis' motility behavior, magnetotaxis, to experimentally provide insights in support of behavior as an unambiguous, sensitive biosignature, and magnetic forces as a prescreening option. Using a magnetotactic bacterial species, Magnetospirillum magneticum, we conducted a lab sensitivity experiment comparing PCR with the hanging drop behavioral assay, using a dilution series. The hanging drop behavioral assay visually shows the motility of MTB toward magnetic poles. Our findings reveal that the behavioral assay exhibits higher sensitivity in the detection of M. magneticum when compared to the established PCR protocol. While both methods present similar detection sensitivities at high concentrations, at ≥ 10–7 fold dilutions, the behavioral method proved more sensitive. The behavioral method can detect bacteria even when samples are diluted at 10–9. Comparable results were obtained with environmental samples from the Hula Valley. We propose behavioral cues as valuable biosignatures in the ongoing efforts of life detection in unexplored aquatic habitats on Earth and to stimulate and support discussions about how to detect extant life beyond Earth. Generic and robust behavioral assays can represent a methodological revolution. [ABSTRACT FROM AUTHOR]

The possible existence of a microbial community in the venusian clouds is one of the most intriguing hypotheses in modern astrobiology. Such a community must be characterized by a high survivability potential under severe environmental conditions, the most extreme of which are very low pH levels and water activity. Considering different scenarios for the origin of life and geological history of our planet, a few of these scenarios are discussed in the context of the origin of hypothetical microbial life within the venusian cloud layer. The existence of liquid water on the surface of ancient Venus is one of the key outstanding questions influencing this possibility. We link the inherent attributes of microbial life as we know it that favor the persistence of life in such an environment and review the possible scenarios of life's origin and its evolution under a strong greenhouse effect and loss of water on Venus. We also propose a roadmap and describe a novel methodological approach for astrobiological research in the framework of future missions to Venus with the intent to reveal whether life exists today on the planet. [ABSTRACT FROM AUTHOR]

The search for life beyond Earth necessitates a rigorous and comprehensive examination of biosignatures, the types of observable imprints that life produces. These imprints and our ability to detect them with advanced instrumentation hold the key to our understanding of the presence and abundance of life in the universe. Biosignatures are the chemical or physical features associated with past or present life and may include the distribution of elements and molecules, alone or in combination, as well as changes in structural components or physical processes that would be distinct from an abiotic background. The scientific and technical strategies used to search for life on other planets include those that can be conducted in situ to planetary bodies and those that could be observed remotely. This chapter discusses numerous strategies that can be employed to look for biosignatures directly on other planetary bodies using robotic exploration including those that have been deployed to other planetary bodies, are currently being developed for flight, or will become a critical technology on future missions. Search strategies for remote observations using current and planned ground-based and space-based telescopes are also described. Evidence from spectral absorption, emission, or transmission features can be used to search for remote biosignatures and technosignatures. Improving our understanding of biosignatures, their production, transformation, and preservation on Earth can enhance our search efforts to detect life on other planets. [ABSTRACT FROM AUTHOR]

Organisms act stochastically. A not uncommon view in the ecological literature is that this is mainly due to the observer having insufficient information or a stochastic environment—and not partly because organisms themselves respond with inherent unpredictability. In this study, I compile the evidence that contradicts that view. Organisms generate uncertainty internally, which results in irreducible stochastic responses. I consider why: for instance, stochastic responses are associated with greater adaptability to changing environments and resource availability. Over longer timescales, biologically generated uncertainty influences behavior, evolution, and macroecological processes. Indeed, it could be stated that organisms are systems defined by the internal generation, magnification, and record-keeping of uncertainty as inputs to responses. Important practical implications arise if organisms can indeed be defined by an association with specific classes of inherent uncertainty: not least that isolating those signatures then provides a potential means for detecting life, for considering the forms that life could theoretically take, and for exploring the wider limits to how life might become distributed. These are all fundamental goals in astrobiology. [ABSTRACT FROM AUTHOR]

We report a simple, inexpensive design of a fluorescence microscope with light-emitting diode (LED) excitation for detection of labeled and unlabeled microorganisms in mineral substrates. The use of deep UV (DUV) excitation with visible emission requires no specialized optics or slides and can be implemented easily and inexpensively using an oblique illumination geometry. DUV excitation (<280 nm) is preferable to near UV (365 nm) for avoidance of mineral autofluorescence. When excited with DUV, unpigmented bacteria show two emission peaks: one in the near UV ∼320 nm, corresponding to proteins, and another peak in the blue to green range, corresponding to flavins and/or reduced nicotinamide adenine dinucleotide (NADH). Many commonly used dyes also show secondary excitation peaks in the DUV, with identical emission spectra and quantum yields as their primary peak. However, DUV fails to excite key biosignature molecules, especially chlorophyll in cyanobacteria. Visible excitation (violet to blue) also results in less mineral autofluorescence than near UV, and most autofluorescence in the minerals seen here is green, so that red dyes and red autofluorescence of chlorophyll and porphyrins are readily distinguished. The pairing of DUV and near UV or visible excitation, with emission across the visible, represents the most thorough approach to detection of labeled and unlabeled bacteria in soil and rock. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ultra wideband (UWB) radar life detection technology has the advantages of low power consumption, good penetration, and high confidentiality. It is beneficial for improving the survival rate of trapped personnel after disasters. This paper systematically summarizes the research progress and current status of UWB radar life detection technology both domestically and internationally. According to the different forms of transmitted signals, UWB radar life detection technology is divided into continuous wave radar life detection technology and pulse wave radar life detection technology. The principles and application advantages of the two detection technologies are introduced respectively. Based on the respective features of continuous wave radar life detection technology and pulse wave radar life detection technology, this paper analyzes the key technologies of UWB radar life detection from three perspectives: detection signal transmission, echo signal preprocessing, and life signal extraction and analysis, and summarizes the research status of the three key technologies. The paper proposes prospects for the research on UWB radar life detection technology. The technology breaks through the hardware performance of life detector transceivers, improves the transmission signal bandwidth, and optimizes RF power amplification technology to increase the detection distance through walls. The technology comprehensively utilizes multiple feature extraction methods and intelligent pattern classification methods, as well as new generation information technologies such as artificial intelligence, big data, and cloud computing, to improve the precision of target recognition. The technology develops a human target recognition and positioning equipment based on multi input multi output radar and a high-precision distributed networked fully polarized UWB radar life detector to enhance the dimension of detection results.

Astrobiology aims to determine the distribution and diversity of life in the universe. But as the word "biosignature" suggests, what will be detected is not life itself, but an observation implicating living systems. Our limited access to other worlds suggests this observation is more likely to reflect out‐of‐equilibrium gasses than a writhing octopus. Yet, anything short of a writhing octopus will raise skepticism about what has been detected. Resolving that skepticism requires a theory to delineate processes due to life and those due to abiotic mechanisms. This poses an existential question for life detection: How do astrobiologists plan to detect life on exoplanets via features shared between non‐living and living systems? We argue that you cannot without an underlying theory of life. We illustrate this by analyzing the hypothetical detection of an "Earth 2.0" exoplanet. Without a theory of life, we argue the community should focus on identifying unambiguous features of life via four areas: examining life on Earth, building life in the lab, probing the solar system, and searching for technosignatures. Ultimately, we ask, what exactly do astrobiologists hope to learn by searching for life? [ABSTRACT FROM AUTHOR]

The concept of a biosignature is widely used in astrobiology to suggest a link between some observation and a biological cause, given some context. The term itself has been defined and used in several ways in different parts of the scientific community involved in the search for past or present life on Earth and beyond. With the ongoing acceleration in the search for life in distant time and/or deep space, there is a need for clarity and accuracy in the formulation and reporting of claims. Here, we critically review the biosignature concept(s) and the associated nomenclature in light of several problems and ambiguities emphasized by recent works. One worry is that these terms and concepts may imply greater certainty than is usually justified by a rational interpretation of the data. A related worry is that terms such as "biosignature" may be inherently misleading, for example, because the divide between life and non-life—and their observable effects—is fuzzy. Another worry is that different parts of the multidisciplinary community may use non-equivalent or conflicting definitions and conceptions, leading to avoidable confusion. This review leads us to identify a number of pitfalls and to suggest how they can be circumvented. In general, we conclude that astrobiologists should exercise particular caution in deciding whether and how to use the concept of biosignature when thinking and communicating about habitability or life. Concepts and terms should be selected carefully and defined explicitly where appropriate. This would improve clarity and accuracy in the formulation of claims and subsequent technical and public communication about some of the most profound and important questions in science and society. With this objective in mind, we provide a checklist of questions that scientists and other interested parties should ask when assessing any reported detection of a "biosignature" to better understand exactly what is being claimed. [ABSTRACT FROM AUTHOR]

The origin of life and the detection of alien life have historically been treated as separate scientific research problems. However, they are not strictly independent. Here, we discuss the need for a better integration of the sciences of life detection and origins of life. Framing these dual problems within the formalism of Bayesian hypothesis testing, we demonstrate via simple examples how high confidence in life detection claims require either (1) a strong prior hypothesis about the existence of life in a particular alien environment, or conversely, (2) signatures of life that are not susceptible to false positives. As a case study, we discuss the role of priors and hypothesis testing in recent results reporting potential detection of life in the venusian atmosphere and in the icy plumes of Enceladus. While many current leading biosignature candidates are subject to false positives because they are not definitive of life, our analyses demonstrate why it is necessary to shift focus to candidate signatures that are definitive. This indicates a necessity to develop methods that lack substantial false positives, by using observables for life that rely on prior hypotheses with strong theoretical and empirical support in identifying defining features of life. Abstract theories developed in pursuit of understanding universal features of life are more likely to be definitive and to apply to life-as-we-don't-know-it. We discuss Molecular Assembly theory as an example of such an observable which is applicable to life detection within the solar system. In the absence of alien examples these are best validated in origin of life experiments, substantiating the need for better integration between origins of life and biosignature science research communities. This leads to a conclusion that extraordinary claims in astrobiology (e.g., definitive detection of alien life) require extraordinary explanations, whereas the evidence itself could be quite ordinary. [ABSTRACT FROM AUTHOR]

An ideal life detection instrument would have high sensitivity but be insensitive to abiotic processes and would be capable of detecting life with alternate molecular structures. In this study, we propose that catalytic activity can be the basis of a nearly ideal life detection instrument. There are several advantages to catalysis as an agnostic life detection method. Demonstrating catalysis does not necessarily require culturing/growing the alien life and in fact may persist even in dead biomass for some time, and the amplification by catalysis is large even by minute amounts of catalysts and, hence, can be readily detected against abiotic background rates. In specific, we propose a hydrolytic catalysis detection instrument that could detect activity in samples of extraterrestrial organic material from unknown life. The instrument uses chromogenic assay-based detection of various hydrolytic catalytic activities, which are matched to corresponding artificial substrates having the same, chromogenic (preferably fluorescent) upon release, group; D- and L-enantiomers of these substrates can be used to also answer the question whether unknown life is chiral. Since catalysis is a time-proportional product-concentration amplification process, hydrolytic catalytic activity can be measured on a sample of even a minute size, and with instruments based on, for example, optofluidic chip technology. [ABSTRACT FROM AUTHOR]

Flow cytometry is a potential technology for in situ life detection on icy moons (such as Enceladus and Europa) and on the polar ice caps of Mars. We developed a method for using flow cytometry to positively identify four classes of biomarkers using exogenous fluorescent stains: nucleic acids, proteins, carbohydrates, and lipids. We demonstrated the effectiveness of exogenous stains with six known organisms and known abiotic material and showed that the cytometer is easily able to distinguish between the known organisms and the known abiotic material using the exogenous stains. To simulate a life-detection experiment on an icy world lander, we used six natural samples with unknown biotic and abiotic content. We showed that flow cytometry can identify all four biomarkers using the exogenous stains and can separate the biotic material from the known abiotic material on scatter plots. Exogenous staining techniques would likely be used in conjunction with intrinsic fluorescence, clustering, and sorting for a more complete and capable life-detection instrument on an icy moon lander. [ABSTRACT FROM AUTHOR]

We present a comparative study of the methods used in the search for extraterrestrial microorganism life, including a summary table where different life-detection techniques can be easily compared as an aid to mission and instrument design aimed at life detection. This is an extension of previous study, where detection techniques for a series of target characteristics and molecules that could constitute a positive life detection were evaluated. This comparison has been extended with a particular consideration to sources of false positives, the causes of negative detection, the results of detection techniques when presented regarding terrestrial life, and additional science objectives that could be achieved outside the primary aim of detecting life. These additions address both the scientific and programmatic side of exploration mission design, where a successful proposal must demonstrate probable outcomes and be able to return valuable results even if no life is found. The applicability of the life detection techniques is considered for Earth life, Earth-independent life (life emerging independently from that on Earth,) and Earth-kin life (sharing a common ancestor with life on Earth), and techniques effective in detecting Earth life should also be useful in the detection of Earth-kin life. However, their applicability is not guaranteed for Earth-independent life. As found in our previous study, there exists no realistic single detection method that can conclusively determine the discovery of extraterrestrial life, and no method is superior to all others. In this study, we further consider combinations of detection techniques and identify imaging as a valuable addition to molecule detection methods, even in cases where there is insufficient resolution to observe the detailed morphology of a microbial cell. The search for extraterrestrial life is further divided into a survey-and-detection and analysis-and-conclusion step. These steps benefit from different detection techniques, but imaging is necessary for both parts. [ABSTRACT FROM AUTHOR]

Growing evidence of the potential habitability of Ocean Worlds across our solar system is motivating the advancement of technologies capable of detecting life as we know it—sharing a common ancestry or physicochemical origin with life on Earth—or don't know it, representing a distinct emergence of life different than our one known example. Here, we propose the Electronic Life-detection Instrument for Enceladus/Europa (ELIE), a solid-state single-molecule instrument payload that aims to search for life based on the detection of amino acids and informational polymers (IPs) at the parts per billion to trillion level. As a first proof-of-principle in a laboratory environment, we demonstrate the single-molecule detection of the amino acid L-proline at a 10 μM concentration in a compact system. Based on ELIE's solid-state quantum electronic tunneling sensing mechanism, we further propose the quantum property of the HOMO–LUMO gap (energy difference between a molecule's highest energy-occupied molecular orbital and lowest energy-unoccupied molecular orbital) as a novel metric to assess amino acid complexity. Finally, we assess the potential of ELIE to discriminate between abiotically and biotically derived α-amino acid abundance distributions to reduce the false positive risk for life detection. Nanogap technology can also be applied to the detection of nucleobases and short sequences of IPs such as, but not limited to, RNA and DNA. Future missions may utilize ELIE to target preserved biosignatures on the surface of Mars, extant life in its deep subsurface, or life or its biosignatures in a plume, surface, or subsurface of ice moons such as Enceladus or Europa. One-Sentence Summary: A solid-state nanogap can determine the abundance distribution of amino acids, detect nucleic acids, and shows potential for detecting life as we know it and life as we don't know it. [ABSTRACT FROM AUTHOR]

In recent years, strong evidence has emerged indicating the potential habitability of the subsurface of Mars. Occasional discharge events that bring subsurface fluids to the surface may carry with them the biological traces of subsurface organisms. Similar events are known to take place on Earth and are frequently associated with long-term mineralogical preservation of organic material, including DNA. Taking advantage of this process may allow for the development of life-detection strategies targeting biosignatures from the more habitable subsurface environment without the need for direct subsurface exploration. To test the potential for this approach to life-detection, we adapted a protocol to extract microbial DNA preserved in carbonate rocks and tested its efficacy in detecting subsurface organisms at a Mars analog site in southeastern Utah, USA, using samples from ancient and modern carbonate deposits associated with natural and artificial springs. Our results indicated that DNA from deep-subsurface organisms preserved in carbonate deposits can remain recoverable for up to 100,000 years, supporting life-detection strategies based on the detection of deep-subsurface biosignatures in surface-exposed rocks on Mars. [ABSTRACT FROM AUTHOR]

Simple Summary: The Antarctic Polar Plateau is one of the most extreme environments on Earth and our knowledge on the microbial diversity inhabiting this region is still limited. The BacFinder project investigated microbial diversity on the snow surface of the Polar Plateau, focusing on the vicinity of the Concordia Antarctic Research Station, to assess the microbial diversity and the potential impact of human presence on such a pristine environment. We found that seasonality was the main driver for both bacterial and fungal assemblages, while biodiversity appeared unaffected by distance from the base. Amplicon sequencing revealed a predominance of Basidiomycota (49%) and Ascomycota (42%) for the fungal component. Bacteroidota (65.8%) is the main representative of the bacterial component. Basidiomycetes are almost exclusively represented by yeast-like fungi. Overall, the study highlighted the impact of human activity on the microbial composition in this environment and may provide critical information on the habitability of extra-terrestrial analogs on our planet and on the possibility to explore the surfaces of icy worlds. The French–Italian Concordia Research Station, situated on the Antarctic Polar Plateau at an elevation of 3233 m above sea level, offers a unique opportunity to study the presence and variation of microbes introduced by abiotic or biotic vectors and, consequently, appraise the amplitude of human impact in such a pristine environment. This research built upon a previous work, which explored microbial diversity in the surface snow surrounding the Concordia Research Station. While that study successfully characterized the bacterial assemblage, detecting fungal diversity was hampered by the low DNA content. To address this knowledge gap, in the present study, we optimized the sampling by increasing ice/snow collected to leverage the final DNA yield. The V4 variable region of the 16S rDNA and Internal Transcribed Spacer (ITS1) rDNA was used to evaluate bacterial and fungal diversity. From the sequencing, we obtained 3,352,661 and 4,433,595 reads clustered in 930 and 3182 amplicon sequence variants (ASVs) for fungi and bacteria, respectively. Amplicon sequencing revealed a predominance of Basidiomycota (49%) and Ascomycota (42%) in the fungal component; Bacteroidota (65.8%) is the main representative among the bacterial phyla. Basidiomycetes are almost exclusively represented by yeast-like fungi. Our findings provide the first comprehensive overview of both fungal and bacterial diversity in the Antarctic Polar Plateau's surface snow/ice near Concordia Station and to identify seasonality as the main driver of microbial diversity; we also detected the most sensitive microorganisms to these factors, which could serve as indicators of human impact in this pristine environment and aid in planetary protection for future exploration missions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Good feature engineering is a prerequisite for accurate classification, especially in challenging scenarios such as detecting the breathing of living persons trapped under building rubble using bioradar. Unlike monitoring patients' breathing through the air, the measuring conditions of a rescue bioradar are very complex. The ultimate goal of search and rescue is to determine the presence of a living person, which requires extracting representative features that can distinguish measurements with the presence of a person and without. To address this challenge, we conducted a bioradar test scenario under laboratory conditions and decomposed the radar signal into different range intervals to derive multiple virtual scenes from the real one. We then extracted physical and statistical quantitative features that represent a measurement, aiming to find those features that are robust to the complexity of rescue-radar measuring conditions, including different rubble sites, breathing rates, signal strengths, and short-duration disturbances. To this end, we utilized two methods, Analysis of Variance (ANOVA), and Minimum Redundancy Maximum Relevance (MRMR), to analyze the significance of the extracted features. We then trained the classification model using a linear kernel support vector machine (SVM). As the main result of this work, we identified an optimal feature set of four features based on the feature ranking and the improvement in the classification accuracy of the SVM model. These four features are related to four different physical quantities and independent from different rubble sites. [ABSTRACT FROM AUTHOR]

The search for extant microbial life will be a major focus of future astrobiology missions; however, no direct extant life detection instrumentation is included in current missions to Mars. In this study, we developed the semiautomated MicroLife detection platform that collects and processes environmental samples, detects biosignatures, and characterizes microbial activity. This platform is composed of a drill for sample collection, a redox dye colorimetric system for microbial metabolic activity detection and assessment (μMAMA [microfluidics Microbial Activity MicroAssay]), and a MinION sequencer for biosignature detection and characterization of microbial communities. The MicroLife platform was field-tested on White Glacier on Axel Heiberg Island in the Canadian high Arctic, with two extracted ice cores. The μMAMA successfully detected microbial metabolism from the ice cores within 1 day of incubation. The MinION sequencing of the ice cores and the positive μMAMA card identified a microbial community consistent with cold and oligotrophic environments. Furthermore, isolation and identification of microbial isolates from the μMAMA card corroborated the MinION sequencing. Together, these analyses support the MicroLife platform's efficacy in identifying microbes natively present in cryoenvironments and detecting their metabolic activity. Given our MicroLife platform's size and low energy requirements, it could be incorporated into a future landed platform or rovers for life detection. [ABSTRACT FROM AUTHOR]

Life detection technology using ultra-wideband (UWB) radar is a non-contact, active detection technology, which can be used to search for survivors in disaster rescues. The existing multi-target detection method based on UWB radar echo signals has low accuracy and has difficulty extracting breathing and heartbeat information at the same time. Therefore, this paper proposes a new multi-target localization and vital sign detection method using ultra-wide band radar. A target recognition and localization method based on permutation entropy (PE) and K means++ clustering is proposed to determine the number and position of targets in the environment. An adaptive denoising method for vital sign extraction based on ensemble empirical mode decomposition (EEMD) and wavelet analysis (WA) is proposed to reconstruct the breathing and heartbeat signals of human targets. A heartbeat frequency extraction method based on particle swarm optimization (PSO) and stochastic resonance (SR) is proposed to detect the heartbeat frequency of human targets. Experimental results show that the PE—K means++ method can successfully recognize and locate multiple human targets in the environment, and its average relative error is 1.83%. Using the EEMD–WA method can effectively filter the clutter signal, and the average relative error of the reconstructed respiratory signal frequency is 4.27%. The average relative error of heartbeat frequency detected by the PSO–SR method was 6.23%. The multi-target localization and vital sign detection method proposed in this paper can effectively recognize all human targets in the multi-target scene and provide their accurate location and vital signs information. This provides a theoretical basis for the technical system of emergency rescue and technical support for post-disaster rescue. [ABSTRACT FROM AUTHOR]

We introduce a Bayesian method for guiding future directions for detection of life on exoplanets. We describe empirical and theoretical work necessary to place constraints on the relevant likelihoods, including those emerging from better understanding stellar environment, planetary climate and geophysics, geochemical cycling, the universalities of physics and chemistry, the contingencies of evolutionary history, the properties of life as an emergent complex system, and the mechanisms driving the emergence of life. We provide examples for how the Bayesian formalism could guide future search strategies, including determining observations to prioritize or deciding between targeted searches or larger lower resolution surveys to generate ensemble statistics and address how a Bayesian methodology could constrain the prior probability of life with or without a positive detection. Key Words: Exoplanets-Biosignatures-Life detection-Bayesian analysis. Astrobiology 18, 779-824.

The plume of Enceladus is thought to originate from the dispersion of a liquid source beneath the icy crust. Cryovolcanic activity on Enceladus may present a direct way of accessing material originating from the potentially habitable subsurface ocean. One way to test the hypothesis of whether life is present within the ocean of Enceladus would be to investigate the plume material for the presence of microbial life. In this study, we investigated the entrainment of Bacillus subtilis within Enceladus-like fluids under boiling conditions caused by exposure of the fluids to low pressure. We show that boiling, associated with exposure of a fluid to low pressure, works as a mechanism for dispersing bacteria in Enceladus plume-like environments. Exposure of Enceladus-type fluids (0.01–0.1 molal Na2CO3 and 0.05–0.2 molal NaCl) to low pressure (5 mbar) results in the dispersion of bacteria in droplets that evaporate to produce particles of salt. We find that, for particles with radius (r) ≤ 10 μm, the number of dispersed particles containing cells was between 7.7% and 10.9%. However, for larger particles 10 < r ≤ 50 μm, 64.4% and 56.4% contained cells for lower and upper end-member solutions, respectively. Our results suggest that the gravity-induced size sorting of plume particles will result in plume deposits closer to the vent source containing a larger volume of biological material than within the plume. If life is present in the ocean of Enceladus, we would expect that it would be effectively entrained and deposited on the surface; therefore, it would be accessible with a surface-lander-based instrument. [ABSTRACT FROM AUTHOR]

The Concordia Research Station provides a unique location for preparatory activities for future human journey to Mars, to explore microbial diversity at subzero temperatures, and monitor the dissemination of human-associated microorganisms within the pristine surrounding environment. Amplicon sequencing was leveraged to investigate the microbial diversity of surface snow samples collected monthly over a two-year period, at three distances from the Station (10, 500, and 1000 m). Even when the extracted total DNA was below the detection limit, 16S rRNA gene sequencing was successfully performed on all samples, while 18S rRNA was amplified on 19 samples out of 51. No significant relationships were observed between microbial diversity and seasonality (summer or winter) or distance from the Concordia base. This suggested that if present, the anthropogenic impact should have been below the detectable limit. While harboring low microbial diversity, the surface snow samples were characterized by heterogeneous microbiomes. Ultimately, our study corroborated the use of DNA sequencing-based techniques for revealing microbial presence in remote and hostile environments, with implications for Planetary Protection during space missions and for life-detection in astrobiology relevant targets. [ABSTRACT FROM AUTHOR]

The detection and identification of the building blocks of life, from amino acids to more complex molecules such as certain lipids, is a crucial but highly challenging task for current and future space exploration missions in our Solar System. To date, Gas Chromatography Mass Spectrometry has been the main technology applied. Although it has shown excellent performance in laboratory research, it has not yet been able to provide a conclusive answer regarding the presence or absence of a signature of life, extinct or extant, in space exploration. In this contribution we present the current measurement capabilities of our space prototype laser-based mass spectrometer for organics detection. The developed mass spectrometer currently allows the detection and identification of small organic molecules, such as amino acids and nucleobases, at sample concentrations at the level of femtomole mm-2, using the same measurement protocol. The latter is highly relevant to space exploration, since with the instrumentation in use so far only one class of organics can be measured with one instrument configuration., (Copyright 2025 Andreas Riedo, Nikita J. Boeren, Peter Keresztes Schmidt, Marek Tulej, Peter Wurz. License: This work is licensed under a Creative Commons Attribution 4.0 International License.)

Human-assistance rovers have a broad prospect in the field of space robotics, as a significant number of organizations and researchers have been investing in the design and development of sophisticated rovers for planetary exploration. In order to promote research and development in the design of next-generation MARS rovers, an annual University Rover Challenge (URC) is hosted by the MARS Society in the United States. In this study, we highlight the design and development process of several novel subsystems of a human-assistance planetary exploration rover and their successive integration in the prototype named PHOENIX, which is a rover that participated in the URC 2021. First, a detailed requirement elicitation has been conducted, for designing a conceptual framework for a rover capable of planetary exploration. Secondly, the design and development process has been detailed for five basic subsystems (power, communication, primary-manipulator, chassis with drive, processing) and two mission-specific subsystems (scientific exploration and autonomous navigation), as well as their successive integration into the rover. Afterwards, a detailed evaluation study has been conducted in order to validate the performance of the developed system. Terrain traversability, autonomy in navigation, and sophisticated task execution capabilities have been evaluated individually within this study. Additionally, the capability of the rover in detecting bio-signatures from soil samples using a novel Multiple Bio-molecular Rapid Life Detection (MBLDP-R) protocol has also been evaluated. The developed scientific exploration subsystem is capable of detecting the presence of life from soil samples with a 92% success rate, and from rock samples with a success rate of 93.33%.

A multisensor data fusion algorithm is proposed in this study for life detection in cluttered environments. The method consists of four steps: data acquisition, data preprocessing, data fusion, and result sort. First, four kinds of data (RGB image, RGB video, infrared image, and radar wave) are acquired from three different sensors (RGB camera, infrared camera, and life detection radar). Then, four specified algorithms are used on each data for data preprocessing. Third, an ordered weighted average (OWA)-based data fusion is used to fuse the four single results. The result is a sort of four possible results ($\textit {Alive}$ , $\textit {Dead}$ , $\textit {Animal}$ , and $\textit {None}$). A series of cluttered environments are designed to verify the effectiveness of the proposed method. The results show that the data fusion method can effectively improve the success rate of life detection in cluttered environments. Specifically, the average accuracies of 97.8%, 96.7%, and 89.7% under different distances, light intensities, and shelter, respectively, are obtained. [ABSTRACT FROM AUTHOR]

Raman spectroscopy, an emerging technology for in situ space exploration, has been suggested for life detection for the Europa Lander Mission. However, obtaining spectra of samples from the europan icy shell requires measurements at temperatures down to −233°C, which will affect the Raman spectra of any potential biosignatures. In this study, we obtained Raman spectra of amino acids using a 785 nm Raman system at temperatures ranging down to −196°C, analogous to Europa's surface and near subsurface. Significant Raman band width narrowing and decreasing variance were observed at lower temperatures leading to higher-precision Raman measurements, which required higher spectral resolution that could be as high as 2 cm−1 for full identification of amino acids. Such spectral resolution is much higher than the resolution of contemporary Raman instruments for planetary exploration and may be particularly problematic for miniaturized instruments. Shifting of Raman bands to both higher and lower frequencies by as much as ∼25 cm−1 together with changes in the Raman band intensity were recorded. The emergence of new bands and diminishing of the original bands also occurred for some amino acids. A significantly increased fluorescence background was observed in spectra of fluorescent molecules (i.e., tryptophan). A link between the type of vibrational modes associated with Raman bands and the change in their Raman shift at extreme low temperatures was identified and described. This link offers an exciting new method of molecule identification solely based on the comparison of spectra collected at two different temperatures and could greatly improve the identification capabilities in Raman spectroscopy for a wide array of applications. [ABSTRACT FROM AUTHOR]

Craters of the Moon National Monument and Preserve (CotM) is a strong terrestrial analog for lava tube formations on Mars. The commonality of its basalt composition to Martian lava tubes makes it especially useful for probing how interactions between water, rock, and life have developed over time, and what traces of these microbial communities may be detectable by current flight‐capable instrumentation. Our investigations found that secondary mineral deposits within these caves contain a range of underlying compositions that support diverse and active microbial communities. Examining the taxonomy, activity, and metabolic potential of these communities revealed largely heterotrophic life strategies supported by contributions from chemolithoautotrophs that facilitate key elemental cycles. Finally, traces of these microbial communities were detectable by flight‐capable pyrolysis and wet chemistry gas chromatography‐mass spectrometry methods comparable to those employed by the Sample Analysis at Mars (SAM) instrument aboard the Curiosity rover and the Mars Organic Molecule Analyzer (MOMA) on the upcoming Rosalind Franklin rover. Using a suite of methods for chemical derivatization of organic compounds is beneficial for resolving the greatest variety of biosignatures. Tetramethylammonium hydroxide (TMAH), for example, allowed for optimal resolution of long chain fatty acids. Taken together, these results have implications for the direction of mass spectrometry as a tool for biosignature detection on Mars, as well as informing the selection of sampling sites that could potentially host biosignatures. Plain Language Summary: We investigated lava tubes at Craters of the Moon National Monument and Preserve for their potential to host and preserve evidence of life. Lava tubes are found on both Earth and Mars, and can shield life from extreme environmental conditions such as radiation and temperature fluctuation. We found a variety of mineral deposits on the walls of lava tube caves formed by water‐rock interactions throughout time, which hosted diverse microbial communities. These communities contained the ability to generate energy from both inorganic and organic carbon sources, as well as cycle important nutrients such as nitrogen and sulfur. In addition, we used techniques comparable to those employed aboard the Sample Analysis at Mars instrument on the Curiosity rover to understand whether this life could hypothetically be detected by exploratory missions. Many organic molecules were detected using our techniques, demonstrating that these habitats have the potential to preserve life and its traces on other worlds. Key Points: Genomic results reveal a diverse microbial ecosystem in the lava tubes at Craters of the MoonThere are multiple ways for chemolithotrophic life to harvest energy in this basaltic Mars analog environmentBiosignatures, or traces of life, can be detected in secondary mineral deposits using flight‐like techniques [ABSTRACT FROM AUTHOR]

Before the first humans depart for Mars in the next decade, hundreds of tons of martian water-ice must be harvested to produce propellant for the return vehicle, a process known as in situ resource utilization (ISRU). We describe here an instrument, the Agnostic Life Finder (ALF), that is an inexpensive life-detection add-on to ISRU. ALF exploits a well-supported view that informational genetic biopolymers in life in water must have two structural features: (1) Informational biopolymers must carry a repeating charge; they must be polyelectrolytes. (2) Their building blocks must fit into an aperiodic crystal structure; the building blocks must be size-shape regular. ALF exploits the first structural feature to extract polyelectrolytes from ∼10 cubic meters of mined martian water by applying a voltage gradient perpendicularly to the water's flow. This gradient diverts polyelectrolytes from the flow toward their respective electrodes (polyanions to the anode, polycations to the cathode), where they are captured in cartridges before they encounter the electrodes. There, they can later be released to analyze their building blocks, for example, by mass spectrometry or nanopore. Upstream, martian cells holding martian informational polyelectrolytes are disrupted by ultrasound. To manage the (unknown) conductivity of the water due to the presence of salts, the mined water is preconditioned by electrodialysis using porous membranes. ALF uses only resources and technology that must already be available for ISRU. Thus, life detection is easily and inexpensively integrated into SpaceX or NASA ISRU missions. [ABSTRACT FROM AUTHOR]

The search for life in Solar System bodies such as Mars and Ocean Worlds (e.g., Europa and Enceladus) is an ongoing and high-priority endeavor in space science, even ∼ five decades after the first life detection mission at Mars performed by the twin Viking landers. However, the in situ detection of biosignatures remains highly challenging, both scientifically and technically. New instruments are being developed for detecting extinct or extant life on Mars and Ocean Worlds due to new technology and fabrication techniques. These instruments are becoming increasingly capable of both detecting and identifying in situ organic biosignatures that are indicative of life and will play a pivotal role in the search for evidence of life through robotic lander missions. This review article gives an overview of techniques used for space missions (gas chromatography, mass spectrometry, and spectroscopy), the further ongoing developments of these techniques, and ion mobility spectrometry. In addition, current developments of techniques used in the next-generation instruments for organic biosignature detection are reviewed; these include capillary electrophoresis, liquid chromatography, biosensors (primarily immunoassays), and nanopore sensing; whereas microscopy, biological assays, and isotope analysis are beyond the scope of this paper and are not covered.

Homochirality is a generic and unique property of all biochemical life and it is considered a universal and agnostic biosignature. Upon interaction with unpolarized light, homochirality induces fractional circular polarization in the light that is scattered from it, which can be sensed remotely. As such, it can be a prime candidate biosignature in the context of future life detection missions and observatories. The linear polarizance of vegetation is also sometimes envisaged as a biosignature, although it does not share the same molecular origin as circular polarization. It is known that linear polarization of surfaces is strongly dependent on the phase angle. The relationship between the phase angle and circular polarization stemming from macromolecular assemblies such as in vegetation, however, remained unclear. In this study, using the average of 27 different species, we demonstrate that the circular polarization–phase angle dependency of vegetation induces relatively small changes in spectral shape and mostly affects the signal magnitude. With these results, we underline the use of circular spectropolarimetry as a promising agnostic biosignature complementary to the use of linear spectropolarimetry and scalar reflectance. [ABSTRACT FROM AUTHOR]

Capillary electrophoresis (CE) is a promising liquid-based technique for in situ chemical analysis on ocean worlds that allows the detection of a wide range of organic molecules relevant to the search for life. CE coupled with mass spectrometry (MS) is particularly valuable as it also enables the discovery of unknown compounds. Here we demonstrate that CE coupled to MS via electrospray ionization (ESI) can readily analyze samples containing up to half the saturation levels of salts relevant to ocean worlds when using 5 M acetic acid as the separation media. A mixture containing amino acids, peptides, nucleobases, and nucleosides was analyzed in the presence of two salts, NaCl and MgSO4, based on their relevance to Europa and Enceladus. We demonstrate here CE-MS limits of detection for these organics ranging from 0.05 to 1 μM (8 to 89 ppb) in the absence of salts. More importantly, we demonstrate here for the first time that organics in the low micromolar range (1–50 μM) are detected by CE-MS in the presence of 3 M NaCl without desalting, preconcentration, or derivatization. This demonstration highlights how CE-MS is uniquely suited for organic analysis on future missions to ocean worlds. [ABSTRACT FROM AUTHOR]

Life detection on Mars is an important topic that includes a direct search for biomarkers. This requires instruments for in situ biomarker detection that are compact, lightweight, and able to withstand operations in space. Solid-state nanopores are excellent candidates that allow fast single-molecule detection. They can withstand high temperatures and be sterilized to minimize planetary contamination. The instruments are portable with low-power requirements. We demonstrate a few key results in advancing the use of nanopores for in-space applications. First, we developed modified deoxyribonucleic acid (DNA) extraction protocols to extract DNA from Mars analog soils. Second, we used silicon nitride nanopores to demonstrate the detection of extracted DNA and corresponding current characteristics. The yields and properties of extracted DNA (e.g., estimated diameters) varied somewhat by soil types, extraction methods, and nanopores used. The yields varied from a minimum of 0.9 ng DNA/g soil for a magnesium carbonate sample from Lake Salda to a maximum of 210 ng DNA/g soil for a calcium carbonate sample from Trona Pinnacles. For a given soil type, yields from different methods varied by a factor of up to 50. These observations motivate future studies with a broader range of Mars-like soils and improved instruments to increase signal-to-noise-ratio at higher measurement bandwidths. [ABSTRACT FROM AUTHOR]

Copyright of Il Colle di Galileo is the property of Firenze University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the study of microbial life, microscopy plays a unique role due to its ability to detect ordered structure, motility, and fluorescence signals. As such it has also recently gained attention in the context of searching for extant life on distant Solar System bodies bearing liquid water. In this paper we introduce a multi-modal volumetric microscopy system for potential future spaceflight missions that combines digital holographic microscopy (DHM) and volume fluorescence imager (VFI), which are volumetric imaging methods that provide high-resolution, high-throughput examination of liquid samples. DHM provides information on the absorption, morphology, and motility of imaged objects without requiring the use of contrast agents. On the other hand, VFI based on light field microscopy focuses on the fluorescence signals from the sample to observe specific structures dyed with targeted contrast agents or providing unique autofluorescence signals. We also present an autonomous sample handling and data acquisition system to allow for an autonomous mission to distant planets or moons, or for autonomous use in bodies of water on Earth. The full system, named ELVIS, or Extant Life Volumetric Imaging System, is capable of autonomously surveying a liquid sample to extract morphology, motility, and fluorescence signals of extant microbial life.