A model of Martian ecology
Hypothetical anaerobic ecological system for Mars environment, and suggested life detection experiments
LIFE DETECTOR↗
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U.S. planetary protection program - Implementation highlights
The implementation of the United States planetary protection program, intended to prevent the contamination of the celestial bodies in the solar system during their exploration, in recent interplanetary projects is reviewed. The shift in planetary protection policy from that of absolute sterilization to a probabilistic approach is noted. Attention is then given to the use of microbiological assay, organic materials inventory, microbial burden reduction, contamination control, trajectory biasing and the analysis and identification of contaminating processes for purposed of planetary protection for the Pioneer 10 and 11, Viking and Voyager projects. The success of these measures, as demonstrated by the prevention of accidental planetary impact and the failure to detect terrestrial organisms by the Viking life detection experiments, is pointed out.
Barengoltz, J.↗
Identifying Molecules as Biosignatures with Assembly Theory and Mass Spectrometry
The search for evidence of life elsewhere in the universe is hard because it is not obvious what signatures are unique to life. Here we postulate that complex molecules found in high abundance are universal biosignatures as they cannot form by chance. To explore this, we developed the first intrinsic measure of molecular complexity that can be experimentally determined, and this is based upon a new approach called assembly theory which gives the molecular assembly number (MA) of a given molecule. MA allows us to compare the intrinsic complexity of molecules using the minimum number of steps required to construct the molecular graph starting from basic objects, and a probabilistic model shows how the probability of any given molecule forming randomly drops dramatically as its MA increases. To map chemical space, we calculated the MA of ca. 2.5 million compounds, and collected data which showed the complexity of a molecule can be experimentally determined by using three independent techniques including infra-red spectroscopy, nuclear magnetic resonance, and by fragmentation in a mass spectrometer, and this data has an excellent corelation with the values predicted from our assembly theory. We then set out to see if this approach could allow us to identify molecular biosignatures with a set of diverse samples from around the world, outer space, and the laboratory including prebiotic soups. The results show that there is a non-living to living threshold in MA complexity and the higher the MA for a given molecule, the more likely that it had to be produced by a biological process. This work demonstrates it is possible to use this approach to build a life detection instrument that could be deployed on missions to extra-terrestrial locations to detect biosignatures, map the extent of life on Earth, and be used as a molecular complexity scale to quantify the constraints needed to direct prebiotically plausible processes in the laboratory. Such an approach is vital if we are going to find new life elsewhere in the universe or create de-novo life in the lab.
Stuart M Marshall↗
FEASIBILITY OF OPTICAL ROTATORY DISPERSION METHODS APPLIED TO THE DETECTION OF EXTRATERRESTRIAL LIFE.
Optical rotatory dispersion methods applied to the detection of extraterrestrial life
DETECTION↗
Accessing the Subsurface Biosphere Within Rocks Undergoing Active Low-Temperature Serpentinization in the Samail Ophiolite (Oman Drilling Project)
The Oman Drilling Project established an “Active Alteration” multi-borehole observatory in peridotites undergoing low-temperature serpentinization in the Samail Ophiolite. The highly serpentinized rocks are in contact with strongly reducing fluids. Distinct hydrological regimes, governed by differences in rock porosity and fracture density, give rise to steep redox (Eh +200 to –750 mV) and pH (pH range 8.5–11.2) gradients within the 300–400 m deep boreholes. The serpentinites and fluids host an active subsurface ecosystem. Microbial cell abundances in serpentinite vary at least six orders of magnitude, from ≤3.5 × 10 1 to 2.9 × 10 7 cells/g. Low levels of biological sulfate reduction (2–1,000 fmol/cm 3 /day) can be detected in rock cores, particularly in rocks in contact with reduced groundwaters with pH < 10.5. Thermodesulfovibrio is the predominant sulfate reducer identified via metagenomic sequencing of adjacent groundwater communities. Here, we infer that transport and reaction of microbially generated sulfide with the serpentine and brucite assemblages gives rise to optical darkening and sulfide overprinting, including the formation of tochilinite-vallerite group minerals, potentially serving as an indicator that this system is inhabited by microbial life. Olivine mesh-cores replaced with ferroan brucite and minor awaruite, abundant veins containing hydroandradite garnet and polyhedral serpentine, and late-stage carbonate veins are suggested as targets for future spatially resolved life-detection investigations. The high-quality whole-round core samples that have been preserved can be further probed to define how life distributes itself and functions within a system where chemical disequilibria are sustained by low-temperature water/rock interaction, and how biosignatures of in situ microbial activity are generated.
58 GEOSCIENCES↗
Opportunities and Limitations of Nuclear Magnetic Resonance Spectroscopy in Astrobiology
For decades, Nuclear Magnetic Resonance (NMR) spectroscopy has been utilized as a powerful tool in various scientific disciplines, most prominently in chemistry, to determine molecular structures or monitor reactions. While well established in various fields, NMR applications in astrobiology are still unclear. This work aims to explore the potential of NMR in astrobiology, highlighting strengths but also weaknesses. We illustrate capabilities of NMR with two applications: (1) recently developed methods for position-specific carbon isotope analysis of complex organics; and (2) well-established tools for performing quantitative compositional analysis of complex organic mixtures. By utilizing samples relevant to astrobiology, specifically the amino acid valine and analogue mixtures of organics, we showcase that molecules retain a source dependent and distinct intramolecular carbon isotope fingerprint. We demonstrate that compositional sample analysis provides an independent and complementary line of evidence pointing towards the origin of a molecule or mixture. Together, these NMR tools have the potential to support life detection efforts, and aid in distinguishing between biotic and abiotic samples. Finally, we discuss sensitivity, detection limits, the portability of NMR, and propose how integration with mass-spectrometry techniques will be imperative to enable more targeted and comprehensive analyses relevant to astrobiology, including in-situ analysis but also sample return missions.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Common Scientific and Technological Interests Between Astrobiology and Space Biology
The disciplines of astrobiology (AB) and space biology (SB) clearly have common interests, however they have not been pursued jointly. SB and AB are inextricably linked, both intellectually and technologically. They can now be effectively linked operationally. Cross-cutting joint collaborations will enhance innovation and increase cost effectiveness. Session topics include joint science questions, technologies, instrumentation, and missions. Examples include life detection, overlapping planetary protection concerns, biofilms, radiation, hyper- and hypogravity, applications of artificial intelligence and machine learning, interoperable databases, facilities (i.e., spacecraft, lunar surface efforts, simulation chambers, analog sites, etc.), training opportunities, and other topics relevant to AB and SB joint ventures. We welcome contributions on this very broad topical area to facilitate cross-fertilization of these disciplines that are of great importance to NASA.
astrobiology↗
Extraterrestrial biology.
Book on extraterrestrial biology covering origin processes of life, planets, life detection, etc
LIFE DETECTOR↗
Science Objectives for Flagship-Class Mission Concepts for the Search for Evidence of Life at Enceladus
Cassini revealed that Saturn's Moon Enceladus hosts a subsurface ocean that meets the accepted criteria for habitability with bio-essential elements and compounds, liquid water, and energy sources available in the environment. Whether these conditions are sufficiently abundant and collocated to support life remains unknown and cannot be determined from Cassini data. However, thanks to the plume of oceanic material emanating from Enceladus’ south pole, a new mission to Enceladus could search for evidence of life without having to descend through kilometers of ice. In this article, we outline the science motivations for such a successor to Cassini, choosing the primary science goal to be determining whether Enceladus is inhabited and assuming a resource level equivalent to NASA's Flagship-class missions. We selected a set of potential biosignature measurements that are complementary and orthogonal to build a robust case for any life detection result. This result would be further informed by quantifications of the habitability of the environment through geochemical and geophysical investigations into the ocean and ice shell crust. This study demonstrates that Enceladus’ plume offers an unparalleled opportunity for in situ exploration of an Ocean World and that the planetary science and astrobiology community is well equipped to take full advantage of it in the coming decades.
Enceladus↗
Aseptic Handling of the MOMA Mass Spectrometer After Dry Heat Microbial Reduction
Mars Organic Molecule Analyzer Mass Spectrometer (MOMA-MS) is an instrument in the larger MOMA instrument suite for the European Space Agency (ESA) ExoMars 2020 Rover. As a life-detection instrument on a Mars landing mission, MOMA-MS has very stringent Planetary Protection (PP) bioburden requirements. Within the MOMA instrument suite, the hardware surfaces of the sample path must be cleaned to a level of 0.03 spore/sq m. To meet this requirement, a process called Dry Heat Microbial Reduction (DHMR) is used to decrease the number of viable spores by 4 orders of magnitude. Before DHMR, the hardware is handled using standard cleanroom practices, while after DHMR, all sample path surfaces must be handled aseptically when exposed. Aseptic handling of the sample path involves a number of strategies and protocols including working only in an aseptic ISO class 5 work space, limiting the amount of time of exposure, using sterile garmenting with sterile gloves, and using sterile tools. Before work begins, the aseptic workspace will be tested for bioburden and particle fallout, and all tools that will contact sample path surfaces must be sterilized. During the exposure activity, sterile garments will be worn, sterile tools will be handled in a 2 person set up so that the operator touches only the sterile tool and not the exterior surfaces of the sterile pouch, and the environment will be monitored with active and passive fallout for bioburden and particle levels. Any breach in the planetary protection cleanliness can necessitate repeating DHMR, which not only has significant cost and schedule implications, it also become a risk to hardware that is not rated for repeated long exposures to high temperatures.
Life Detection↗
Characterization of Spacesuit Associated Microbial Communities and their Implications for NASA Missions
Crewed National Aeronautics and Space Administration (NASA) missions to other solar system bodies are currently being planned. One high-profile scientific focus during such expeditions would be life detection, specifically the discovery of past or present microbial life, if they exist. However, both humans and associated objects typically carry a high microbial burden. Thus, it is essential to distinguish between microbes brought with the expedition and those present on the exploring planets. Modern spacesuits are unique, customized spacecraft which provide protection, mobility and life support to crew during spacewalks, yet they vent continuously, and the mobility of microbes through spacesuits has not been studied. To evaluate the microbial colonization of spacesuits, NASA used an Extravehicular Activity swab kit to examine viable microbial populations of 48 samples from spacesuits using both traditional microbiological methods and molecular sequencing methods. The cultivable microbial population ranged from below the detection limit to 9 x 102 colony forming units per 25 cm2 of sample and also significantly varied by the location. The cultivable microbial diversity was dominated by members of Bacillus, Arthrobacter, and Ascomycota. However, 16S rRNA-based viable bacterial burden ranged from 105 to 106 copies per 25 cm2 of sample. Shotgun metagenome sequencing revealed the presence of a diverse microbial population on the spacesuit surfaces, including Curtobacterium and Methylobacterium from across all sets of spacesuits in high abundance. Among bacterial species identified, higher abundance of Cutibacterium acnes, Methylobacterium oryzae, and M. phyllosphaerae reads were documented. The results of this study provide evidence that identical microbial strains may live on the wrist joint, inner gauntlet, and outer gauntlet of spacesuits. This raises the possibility, but does not confirm, that viable microbes are able to migrate between the interior and exterior of spacesuits. Overall, these data provide the first estimate of microbial dispersion from internal to external spacesuit surfaces, which will help future mission planners develop effective planetary protection strategies.
spacesuit↗
Publications of the planetary biology program for 1978: A special bibliography
The planetary events which are responsible for, or related to, the origin, evolution, and distribution of life in the universe are investigated. Bibliographies from chemical evolution, organic geochemistry, life detection, biological adaptation, bioinstrumentation, planetary environments, and origin of life studies are presented.
Pleasant, L. G.↗
Impact-shocked rocks--insights into Archean and extraterrestrial microbial habitats (and sites for prebiotic chemistry?)
Impact-shocked gneiss shocked to greater than 10 GPa in the Haughton impact structure in the Canadian High Arctic has an approximately 25-times greater pore surface area than unshocked rocks. These pore spaces provide microhabitats for a diversity of heterotrophic microorganisms and in the near-surface environment of the rocks, where light levels are sufficient, cyanobacteria. Shocked rocks provide a moisture retaining, UV protected microenvironment. During the Archean, when impact fluxes were more than two orders of magnitude higher than today, the shocked-rock habitat was one of the most common terrestrial habitats and might have provided a UV-shielded refugium for primitive life. These potential habitats are in high abundance on Mars where impact crater habitats could have existed over geologic time periods of billions of years, suggesting that impact-shocked rocks are important sites to search for biomolecules in extraterrestrial life detection strategies. In addition to being favourable sites for life, during the prebiotic period of planetary history impact-shocked rocks might have acted as a site for the concentration of reactants for prebiotic syntheses. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
Evolution, Chemical↗
Sample Handling and Processing on Mars for Future Astrobiology Missions
In most analytical investigations, there is a need to process complex field samples for the unique detection of analytes especially when detecting low concentration organic molecules that may identify extraterrestrial life. Sample processing for analytical instruments is time, resource and manpower consuming in terrestrial laboratories. Every step in this laborious process will have to be automated for in situ life detection. We have developed, and are currently demonstrating, an automated wet chemistry preparation system that can operate autonomously on Earth and is designed to operate under Martian ambient conditions. This will enable a complete wet chemistry laboratory as part of future missions. Our system, namely the Automated Sample Processing System (ASPS) receives fines, extracts organics through solvent extraction, processes the extract by removing non-organic soluble species and delivers sample to multiple instruments for analysis (including for non-organic soluble species).
Beegle, Luther↗
MEAD In-situ Sampling and Testing at Haughton Crater
The Mars Exploration through Analog-site Drilling (MEAD) project is designed to demonstrate the feasibility and scientific value of robotic drilling missions to Mars in the search for evidence of past or extant life. MEAD conducts high-fidelity field simulations integrating drilling, autonomous operations, and in-situ life-detection and mineralogical instruments. The project tests the Signs of Life Detector (SOLID), proposed for the 2019 Discovery Mars Icebreaker mission, and ARIA (Astronaut Raman Instrument for ISRU and Astrobiology), which provides mineral identification and detects trace organics and volatiles, including indicators of organic thermal maturity. Because current and planned Mars drilling missions operate largely “blind,” MEAD also evaluates the use of drill-induced vibrations recorded by deployed geophones to enable local subsurface mapping for improved targeting of drilling and sampling. In August 2025, MEAD completed its first-year field deployment to Haughton Crater in the Canadian High Arctic, an established Mars impact-crater terrestrial analog site, bringing a Honeybee Robotics TRIDENT drill with applied automation, alongside ARIA, SOLID, and FleetSpace geophones.
Haughton Crater↗
Viking - The exploration of Mars
The Viking 1 and 2 spacecraft were launched in August and September, 1975 on a ten month journey to begin an in depth study of the nature, origin and evolution of Mars. Upon arrival at Mars, the previously selected Viking 1 landing site was found to be unsuitable and a new site was selected by means of cameras mounted on the Viking orbiter, which also revealed features suggesting a history of liquid water on the Martian surface. Once the new site in the Cryse basin was selected, the Viking 1 lander separated from the orbiter and landed on July 20, 1976, followed by the Viking 2 lander in August, 1976 at a site considerably to the north of the first site. At the two sites, scanning facsimile cameras allowed the panoramic imaging of the terrain and measurements were made of local atmospheric and soil compositions, temperatures, pressures, winds and seasonal changes. Soil analyzers have not detected the presence of organic materials at these sites, and although the results of the life detection experiments are ambiguous, the likelihood of life on Mars seems extremely remote.
Young, R. S.↗
The Blue Dot Workshop: Spectroscopic Search for Life on Extrasolar Planets
This workshop explored the key questions and challenges associated with detecting life on an extrasolar planet. The final product will be a NASA Conference Publication which includes the abstracts from 21 talks, summaries of key findings, and recommendations for future research. The workshop included sessions on three related topics: the biogeochemistry of biogenic gases in the atmosphere, the chemistry and spectroscopy of planetary atmospheres, and the remote sensing of planetary atmospheres and surfaces. With the observation that planetary formation is probably a common phenomenon, together with the advent of the technical capability to locate and describe extrasolar planets, this research area indeed has an exciting future.
Des Marais, David J.↗
Sample Processor for Life on Icy Worlds (SPLIce): Monolithic Manifold-Based System to Recover, Prepare, and Deliver Samples and Standards to Instrumentation Suites for Ocean World Life-Search Missions
A claim of life detection on one of the solar system’s icy ocean worlds would necessitate extraordinarily convincing evidence. Limited energy availability in the oceans of such bodies as Europa and Enceladus argues for microbes as most probable among possible life forms, but evidence of their existence in the surface layers of an icy moon or in a frozen plume ejected into space could take various forms, pointing to instrumentation suites as a preferred means to detect diverse molecular and morphological life indicators. Multiple disparate categories of positive detections could provide truly convincing evidence from samples that may be only a few micro-liters. SPLIce’s Foundation. Teams led by NASA’s Ames Research Center have developed and operated numerous small, live-biology and astrobiology science payloads in space over two decades. Since 2016, we have adapted and augmented their biological sample-handling systems to create compact, robust search-for-life fluidic processors designed to function after a decade or more in transit, in environments with very little gravity and lots of radiation: up to 100’s of kilorads.
Instrumentation suite↗