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Project Reports

• Advancing Methods for the Analyses of Organic Molecules in Sediments

  Eigenbrode’s research focuses on understanding the formation and preservation of organic and isotopic sedimentary records of ancient Earth and Mars. To this end, and as part of GCA’s Theme IV effort, Eigenbrode seeks to overcome sampling and analytical challenges associated with organic analyses of samples relevant to astrobiology. She modifies and develops methods of contamination tracking, sampling, and analysis (primarily gas chromatography mass spectrometry, GCMS) that improve the recovery of meaningful observations and provide protocol guidance for future astrobiological missions.

  ROADMAP OBJECTIVES: 2.1 2.2 7.1

• Cosmic Distribution of Chemical Complexity

  This project explores the connections between chemistry in space and the origin of life. It is comprised of three tightly interwoven tasks. We track the formation and evolution of chemical complexity in space starting with simple carbon-rich molecules such as formaldehyde and acetylene. We then move on to more complex species including amino acids, nucleic acids and polycyclic aromatic hydrocarbons. The work focuses on carbon-rich species that are interesting from a biogenic perspective and on understanding their possible roles in the origin of life on habitable worlds. We do this by measuring the spectra and chemistry of analog materials in the laboratory, by remote sensing with small spacecraft, and by analysis of extraterrestrial samples returned by spacecraft or that fall to Earth as meteorites. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.2 3.4 4.3 7.1 7.2

• Project 1A: Detection of Biosignatures in Extreme Environments and Analogs for Mars

  Sulfate, a chemical form containing sulfur and oxygen, is present in ocean water and is a component of minerals on Earth and on Mars, created by evaporation of such water. We have been measuring variations in the relative abundances of naturally-occurring, non-radioactive oxygen isotopes in sulfate to indicate what processes were involved in sulfate formation: for example microbes gaining energy from sulfide or via a non-biological route. A precursor chemical in the formation of sulfate is sulfite, containing sulfur and just a little less oxygen. We have shown recently that the oxidation of sulfite (adding more oxygen), governs the oxygen isotope composition of sulfate. This work will be of significant importance in helping us to understand conditions of formation of ancient minerals.

  ROADMAP OBJECTIVES: 5.3 7.1

• Biosignatures in Ancient Rocks – Kasting Group

  The work by Ramirez concerned updating the absorption coefficients in our 1-D climate model. Harman’s work consisted of developing a 1-D code for modeling hydrodynamic escape of hydrogen from rocky planets.

  ROADMAP OBJECTIVES: 1.1 3.2 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2

• Task 1.1.1: Leaching of Radiogenic Potassium From Titan’s Core Into Its Ocean

  Working with graduate student Jason Hofgartner and NAI collaborator Christophe Sotin, we modeled the equilibrium chemistry of potassium at high pressure in the interior aqueous media in Saturn’s moon Titan to determine the extent of potassium leaching. This, in turn, allows us to test the hydrated silicate core model proposed by J. Castillo-Rogez and NAI Titan deputy PI Jonathan Lunine.

  ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.2 7.1

• Investigation 1: Habitability of Icy Worlds

  Habitability of Icy Worlds investigates the habitability of liquid water environments in icy worlds, with a focus on what processes may give rise to life, what processes may sustain life, and what processes may deliver that life to the surface. Habitability of Icy Worlds investigation has three major objectives. Objective 1, Seafloor Processes, explores conditions that might be conducive to originating and supporting life in icy world interiors. Objective 2, Ocean Processes, investigates the formation of prebiotic cell membranes under simulated deep-ocean conditions, and Objective 3, Ice Shell Processes, investigates astrobiological aspects of ice shell evolution.

  ROADMAP OBJECTIVES: 2.1 2.2 3.2 4.1 5.1 5.2 5.3 6.2 7.1 7.2

• Advancing Techniques for in Situ Analysis of Complex Organics: Laser Mass Spectrometry of Planetary Materials

  This line of work within the Goddard Center for Astrobiology (GCA) seeks to connect key science objectives related to understanding organics in our solar system to specific techniques and protocols that may enable us to achieve those objectives with in situ investigations. In particular, laser mass spectrometry (MS) techniques are being developed for analysis of complex, nonvolatile organic molecules, such as those that might be found at Mars, Titan, comets, and other planetary bodies, with limited chemical sample manipulation, preparation, and processing (as may be required by flight missions). The GCA laser MS effort is complementary to both (i) instrument development work supported by NASA programs such as ASTID, PIDDP, and MatISSE, to forward the design and testing of new prototype spaceflight hardware, and (ii) ongoing research and development within Theme 4 of the GCA, concerning analytical chemical sample analysis as well as across GCA (particularly with Theme 3) to define combined analysis techniques that may affect future mission design. There are additionally aspects of this effort that relate to understanding synthetic pathways for certain complex organics in planetary environments. Areas of activity with GCA support during this period included: * Comparative study of prompt and two-step laser desorption MS (LDMS) analyses * Development of protocols for induced molecular dissociation and tandem mass spectrometry (MS/MS) * Mars analog analyses using laser TOF-MS, ion trap MS, and SAM-like protocols

  ROADMAP OBJECTIVES: 2.1 2.2 3.2 7.1

• Habitability, Biosignatures, and Intelligence

  Understanding the nature and distribution of habitable environments in the Universe is one of the primary goals of astrobiology. Based on the only example of life we know, we have devel-oped various concepts to predict, detect, and investigate habitability, biosignatures and intelli-gence occurrence in the near-solar environment. In particular, we are searching for water vapor in atmospheres of extrasolar planets and protoplanets, developing techniques for remote detec-tion of photosynthetic organisms on other planets, have detected a possible bio-chemistry sig-nature in Martian clays contemporary with early life on Earth, developed a comprehensive methodology and an interactive website for calculating habitable zones in binary stellar systems, expanded on definitions of habitable zones in the Milky way Galaxy, and proposed a novel ap-proach for searching extraterrestrial intelligence.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 4.1 4.2 6.2 7.1 7.2

• Project 2: Origin and Evolution of Organic Matter in the Solar System

  We conduct observational analytical research on the volatile and organic rich Solar System Bodies by focusing on astronomical surveying of outer solar system objects and performing in-house analyses of meteorite, interplanetary dust particle, and Comet Wild 2/81P samples with an emphasis on characterizing the distribution, state and chemical history of primitive organic matter. We continue to study the mechanism of formation of refractory organic solids in primitive bodies and determine the origin of isotopic anomalies in organic solids in primitive solar system materials.

  ROADMAP OBJECTIVES: 2.2 3.1 7.1

• Project 1C: Compositional and Structural Variations in Dolomite and Ca-Bearing Magnesite From Modern and Ancient Carbonate Sediments

  Low-temperature Ca-Mg carbonates that have a wide range of chemical variation (from high-Mg calcite to Ca-bearing magnesite) may be used as a biosignature. Certain polysaccharides can inhibit aragonite precipitation and promote Ca-Mg-carbonate crystallization. Experiments indicate that ancient low-temperature, non-stoichiometry dolomite with the observed nano-precipitates of Ca-rich phases may be used as a biosignature.

  ROADMAP OBJECTIVES: 7.1 7.2

• Investigation 4: Path to the Flight

  The (Field Instrumentation and) Path to Flight investigation’s purpose is to enable in-situ measurements of organics and biological material with field instrumentation that have high potential for future flight instrumentation. The preceding three Investigations provide a variety of measurable goals used to modify or “tune” instrumentation that can be placed in the field. In addition the members of this Investigation provide new measurement capabilities that have been developed with the specific goal of life-detection. The instrument arsenal goes beyond the commercially available instrumentation and brings next generation imaging spectrometers, chromatographic, and sample extraction devices.

  ROADMAP OBJECTIVES: 2.1 2.2 6.1 7.1

• Astrobiology in Icy Extraterrestrial Environments

  Scientists in the Cosmic Ice Laboratory with the Goddard Center for Astrobiology (GCA) study the formation and stability of molecules under conditions found in outer space. In the past year, studies of amino-acid destruction were continued, a project on the formation of sulfate ions was completed (related to Europa), measurements of the infrared band strengths were published for application to the outer Solar System, and the formation and chemistry of a particularly-versatile interstellar molecule were investigated. All of this work is part of the Comic Ice Laboratory’s continuing contributions to understanding the chemistry of biologically-related molecules and chemical reactions in extra-terrestrial environments.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 7.1 7.2

• Project 1D: Potential for Microbial Iron Reduction in Chocolate Pots Hot Springs, Yellowstone National Park

  Iron biogeochemical cycling in circumneutral pH hot spring systems is an increasingly important astrobiological target, given recent discoveries on Mars by Curiosity. This study explored the potential for microbial reduction of ferric iron Fe(III) in the warm (ca. 40-60 C), circumneutral pH (ca. 6.0-6.5) Chocolate Pots (CP) hot springs in Yellowstone National Park. Endogenous microbial communities were able to reduce native CP Fe(III) oxides, as documented in most probable number (MPN) enumerations and ongoing enrichment culture studies. Microbial communities in the enrichments have been analyzed by high-throughput pyrosequencing of 16S rRNA gene amplicons. The sequencing revealed an abundance of the well-known Fe(III)-reducing bacterial species, Geobacter metallireducens, as well several other novel organisms with the potential to contribute to Fe(III) reduction. A shotgun metagenomic (paired-end Illumina sequencing) analysis of the enrichment cultures is in progress to explore the identity and function of G. metallireducens as well as other less well-characterized organisms in the cultures. Of particular interest are the likely presence of thermotolerance genes in the G. metallireducens metagenome, as well as outer membrane cytochrome genes that may be indicative of other Fe(III)-reducing organisms and provide evidence for pathways of electron flow in these cultures.

  ROADMAP OBJECTIVES: 2.1 5.1 6.1 7.1

• Biosignatures in Extraterrestrial Settings

  We are working on finding potentially habitable extrasolar planets, using a variety of search techniques, and developing some of the technology necessary to find and characterize low mass extrasolar planets. We also work on modeling and numerical techniques relevant to the problem of identifying extrasolar sites for life, and on some aspects of the prospects for life in the Solar System outside the Earth. The ultimate goal is to find signatures of life on nearby extrasolar planets.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 4.1 4.3 6.2 7.1 7.2

• Project 5: Vistas of Early Mars: In Preparation for Sample Return

  To understand the history of life in the solar system requires knowledge of how hydrous minerals form on planetary surfaces, and the role minerals may play in the development of potential life forms. The minerals hematite and jarosite have been identified on Mars and presented as in situ evidence for aqueous activity. This project seeks to understand (i) the conditions required for jarosite and hematite formation and preservation on planetary surfaces, and (ii) the conditions under which their “radiometric clocks” can be reset (e.g., during changes in environmental conditions such as temperature). By investigating the kinetics of noble gases in minerals, known to occur on Mars and Earth, we will be prepared to analyze and properly interpret ages measured on samples from future Mars sample return missions.

  ROADMAP OBJECTIVES: 1.1 2.1 7.1

• Project 5: Geological-Biological Interactions

  We continue to study the intersection between geology and biology. We continue to explore how sub-seafloor interactions support deep ocean hydrothermal ecosystems. We study life’s adaption to extremes of pressure, cold, and salinity. We adapt and apply multiple isotopic sulfur geochemistry towards the understanding of microbial metabolism and as a means of detecting ancient metabolisms recorded in the rock record through characteristic sulfur isotopic signatures. We apply state-of-the-art methods to derive chemical and isotopic biosignatures of life in the Earth’s most ancient rocks.

  ROADMAP OBJECTIVES: 4.1 5.1 6.1 6.2 7.1

• Biosignatures in Relevant Microbial Ecosystems

  PSARC is investigating microbial life in some of Earth’s most mission-relevant modern ecosystems. These environments include the Dead Sea, the Chesapeake Bay impact structure, methane seeps, ice sheets, and redox-stratified Precambrian ocean analogs. We target environments that, when studied, provide fundamental information that can serve as the basis for future solar system exploration. Combining our expertise in molecular biology, geochemistry, microbiology, and metagenomics, and in collaboration with some of the planet’s most extreme explorers, we are deciphering the microbiology, fossilization processes, and recoverable biosignatures from these mission-relevant environments.

  PSARC Ph.D. (now postdoctoral researcher at Caltech) Katherine Dawson published a new paper documenting the anaerobic biodegradation of organic biosignature compounds pristane and phytane. PSARC Ph.D. Daniel Jones (now postdoctoral researcher at U. Minnesota) published a new paper that uses metagenomic data to show how sulfur oxidation in the deep subsurface environments may contribute to the formation of caves and the maintenence of deep subsurface microbial ecosystems. PSARC Ph.D. student Khadouja Harouaka published a new paper that represents some of the first available information about possible Ca isotope biosignatures. Lastly, the Macalady group published a paper showing how ecological models based on available energy resources can be used to predict the distribution of microbial populations in space and time.

  ROADMAP OBJECTIVES: 4.1 4.3 5.1 5.2 5.3 6.1 7.1 7.2

• Project 1F: Organics Exposure in Orbit (OREOcube): A Next-Generation Space Exposure Platform

  The OREOcube (ORganics Exposure in Orbit cube satellite) experiment on the International Space Station (ISS) investigates the effects of solar and cosmic radiation on organic thin films. By depositing organic samples onto inorganic substrates, structural changes and photo-modulated organic-inorganic interactions are examined to study the role that solid mineral surfaces play in the photo-chemical evolution, transport, and distribution of organics. The results of these experiments in low Earth orbit (LEO) allow extrapolation to different solar system and interstellar/interplanetary environments. Organic molecules appropriate for study in thin-film form include biomarkers such as amino acids and nucleobases, as well as polyaromatic hydrocarbons (PAHs), redox molecules, and organosulfur compounds. Inorganic substrates include silicates, metal oxides, iron sulfides, nano-phase iron, and iron-nickel alloys. By measuring changes in the UV-vis-NIR spectra of samples as a function of time in situ on the ISS, OREOcube will provide data sets that capture critical kinetic and mechanistic details of sample reactions that cannot be obtained with current exposure facilities in LEO. Combining in situ, real-time kinetic measurements with post-flight sample analysis will provide time-course studies, as well as in-depth chemical analysis, enabling us to characterize and model the chemistry of organic species associated with mineral surfaces in the astrobiological context.

  ROADMAP OBJECTIVES: 3.1 5.3 7.1

• Project 2A: Magnesium Isotope Fractionation Between Brucite [Mg(OH)2] and Mg Aqueous Species

  Recognition of clay minerals on Noachian martian terranes provides important information on the habitability of early Mars. Magnesium isotopic studies can aid in constraining the paleoenvironmental conditions of these clay deposits. Our goal is to conduct Mg isotope exchange experiments between clay minerals and aqueous Mg solutions to better understand how the formation of clay minerals can produce Mg isotope variability. In Mg-bearing phyllosilicates, octahedrally coordinated Mg2+ cations occur in a sheeted structure that is the same as brucite. Determination of Mg isotope fractionation between brucite and aqueous solution, therefore, may provide insight into the origin of Mg isotope variations during weathering and alteration of silicate rocks. Our results document the distinct Mg isotope signals produced by weathering in the presence of organic ligands, raising the possibility that abiotic weathering may be distinguished from biologically-catalyzed weathering using stable Mg isotopes.

  ROADMAP OBJECTIVES: 1.1 2.1 7.1 7.2

• Developing New Biosignatures

  The development and experimental testing of potential indicators of life is essential for providing a critical scientific basis for the exploration of life in the cosmos. In microbial cultures, potential new biosignatures can be found among isotopic ratios, elemental compositions, and chemical changes to the growth media. Additionally, life can be detected and investigated in natural systems by directing cutting-edge instrumentation towards the investigation of microbial cells, microbial fossils, and microbial geochemical products. Over the next five years, we will combine our geomicrobiological expertise and on-going field-based environmental investigations with a new generation of instruments capable of revealing diagnostic biosignatures. Our efforts will focus on creating innovative approaches for the analyses of cells and other organic material, finding ways in which metal abundances and isotope systems reflect life, and developing creative approaches for using environmental DNA to study present and past life.

  ROADMAP OBJECTIVES: 2.1 3.1 4.1 5.1 7.1

• Project 2B: Origin of Carbonates: Environmental Proxies and Formation Pathways

  Magnesium isotopes can provide insights into past environmental conditions including formation temperatures and sources of Mg for carbonates, including dolomite, which is a common sedimentary carbonate of the geologic rock record. For Mg isotopes to be a useful proxy, the factors that control isotope fractionation during formation of carbonates must be known. Previous experimental studies have provided conflicting results on potential kinetics effects during the inorganic synthesis of Mg-calcite from solution. To resolve these differences, a matrix of 34 laboratory experiments were conducted to independently determine the effects of temperature, precipitation kinetics, and solution composition (e.g.,pCO₂, aqueous Mg/Ca ratio) on Mg- isotope fractionation in the Mg-calcite-aqueous Mg system. Preliminary results suggest that factors in addition to precipitation rate (e.g., aqueous Mg/Ca ratio, pCO₂) may play a role in the fractionation of Mg isotopes in the Mg-calcite-aqueous Mg system.

  ROADMAP OBJECTIVES: 4.1 7.1

• Water and Habitability of Mars and the Moon and Antarctica

  Water plays an important role in shaping the crusts of the Earth and Mars, and now we know it is present inside the Moon and on its surface. We are assessing the water budgets and total inventories on the Moon and Mars by analyzing samples from these bodies.

  We also study local concentrations of water ice on the Moon, Mars, and at terrestrial analogue sites such as Antarctica and Mauna Kea, Hawaii. We are particularly interested in how local phenomena or microclimates enable ice to form and persist in areas that are otherwise free of ice, such as cold traps on the Moon, tropical craters with permafrost, and ice caves in tropical latitudes. We approach these problems with field studies, modeling, and data analysis. We also develop new instruments and exploration methods to characterize these sites. Several of the terrestrial field sites have only recently become available for scientific exploration.

  HI-SEAS (Hawaii Space Exploration Analog and Simulation, hi-seas.org) is a small habitat at a Mars analog site in the saddle area of the Island of Hawaii. It is a venue for conducting research relevant to long-duration human space exploration. We have just completed our first four-month long mission, and are preparing for three more, of four, eight and twelve months in length. The habitat is a 36’ geodesic dome, with about 1000 square feet of floor space over two stories. It is a low-impact temporary structure that can accommodate six crewmembers, and has a kitchen, a laboratory, and a flexible workspace. Although it is not airtight, the habitat does have simulated airlock, and crew-members don mockup EVA suits before going outside. The site is a disused quarry on the side of a cinder/splatter cone, surrounded by young lava fields. There is almost no human activity or plant life visible from the habitat, making it ideal for ICE (isolated/confined/extreme) research.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 5.3 6.1 6.2 7.1

• Molecular Biosignatures: Fossil Record of Animal Biopolymers

  We contributed to a study of the diagenetic products of the animal pigment eumelanin and learned how to recognize melanin-derived products in the fossil record.

  ROADMAP OBJECTIVES: 4.1 4.2 7.1

• Project 2C: Calibrating the ¹³C-¹⁸O (“clumped”) Isotope Temperature Scale

  Determining paleotemperatures in ancient fluid-mineral systems is key to determining ancient habitability. Stable oxygen isotope studies of carbonates have long used changes in ¹⁸O/¹⁶O ratios to infer the temperature from which carbonate precipitated, using a laboratory-calibrated temperature conversion, but this requires knowledge of the ¹⁸O/¹⁶O ratios of the fluid. This is often not known. A relatively new approach is to use the non-random variations in rare C and O isotopes, specifically the preferential enhancement of ¹³C-¹⁸O bonds, which has been shown to be related to temperature and independent of the fluid isotopic composition. Experimental calibrations, however, have been inconsistent, and goal of this project is to reconcile these discrepancies.

  ROADMAP OBJECTIVES: 2.1 4.1 7.1 7.2

• Infrared Detections of Hypervolatiles in Distant Comets – Implications for Chemical Taxonomy

  Most IR taxonomic databases of comets concentrate on objects at heliocentric distances within 2 AU, where water (the main volatile species in comets) is active. In 2012, we found that we could quantify hypervolatiles (such as carbon monoxide and methane) using infrared facilities in comets at distances even beyond Jupiter, where water ice cannot sublime efficiently. This project has focused on a new approach to understand the activity of distant comets using infrared facilities, as well as on the role of hypervolatiles in the onset of activity and the implications for current taxonomic databases of primary volatiles.

  ROADMAP OBJECTIVES: 1.1 3.1 3.2 7.1

• Project 2D: Catalytic Roles of Microbes in Dolomite Crystallization in a Modern Hypersaline Lake

  A key question is if the presence of Mg-bearing carbonates, such as dolomite or proto-dolomite, by itself, represents a biosignature. This proposal is based on the observation that inorganic precipitation of Mg-bearing carbonates is difficult in laboratory settings, possibly reflecting the high Mg dehydration energies in aqueous solutions. New work shows that microbial extracellular polymeric substances substance (EPS) from halophylic archaea from a hypersaline lake can catalyze disordered dolomite precipitation at low-temperature. Mg-rich dolomite can form at 40 degree C. No dolomite precipitates from solutions without the biomass. Low-temperature dolomite with wide range of compositions may therefore be used as a biosignature.

  ROADMAP OBJECTIVES: 6.1 7.1 7.2

• Molecular Biosignatures: Preservation in Mineral-Forming Ecosystems

  Molecular biosignatures are an important and informative means to reconstruct ancient ecosys-tems, especially, in the case of those dominated by microbes. Most microbes leave only fragmentary chemical records and fossilized hard-parts confined to those taxa with mineralized tests. Preservation can be significantly enhanced when these molecular biosignatures are encapsulated in minerals which are actively forming where the microbes are living and where they may be sequestered from the deleterious effects of oxygen and radiation. We studied several such organo-mineral associations comprising carbonate, silica and gypsum and document a diverse range of molecular biosignatures some of which would be preservable over long timescales. These results are relevant for the study of sediments on the ancient earth, but are also useful in predictive sense for the study of minerals on other planets.

  ROADMAP OBJECTIVES: 5.1 5.3 7.1

• Project 2E: Carbonate-Associated Sulfate (CAS) as a Tracer of Ancient Microbial Ecosystems

  The iron carbonate mineral, siderite, in sedimentary rocks is usually formed by microbial processes. The presence of small amounts of metals other than iron, and the stable isotope compositions of carbon and oxygen, give information on the details of the microbial ecosystem that produced it and its environment of formation. In particular, if associated with iron sulfide (pyrite), it indicates the former presence of at least two different microbial metabolic processes. In addition, carbonate minerals can contain trace amounts of the chemical compound sulfate, in which the isotopic compositions of sulfur and oxygen reveal further details of the microbial process if that sulfate can be released unaltered from the minerals. Our first challenge in this project has been to develop a method for releasing the original, preserved sulfate without contaminating it with somewhat similar material produced from oxidation of pyrite as an artifact of the preparation method.

  ROADMAP OBJECTIVES: 5.2 6.1 7.1

• Project 3A: Banded Iron Formation Deposition Across the Archean-Proterozoic Boundary

  Prior to widespread oxygenic photosynthesis, reduced iron, Fe(II), was the dominant form of soluble iron in surface environments on the early Earth, and likely Mars. On Earth, extensive iron deposits, Banded Iron Formations (BIFs), which currently supply the majority of the iron used in our society, largely formed prior to the Great Oxidation Event of ~2.4 Ga age, and yet contain substantial quantities of oxidized iron, Fe(III). The pathways by which these different oxidation states arose remains unclear. In addition, the chemical and isotopic compositions of BIFs have been used as proxies for ancient seawater or paleoenvironments. In competition with this proposal, however, has been use of BIFs as a tracer of microbial iron cycling. To test the use of BIFs as ambient paleoenvironmental proxies or proxies of microbial process, BIFs from South Africa and Australia were examined from the micron scale to the 100’s of meter scales. We find that BIFs tend to record specific pathways of oxidation of Fe(II), as well as reduction of Fe(III), and extensive post-depositional changes, and it may be quite difficult to infer ambient paleoenvironmental conditions form such deposits.

  ROADMAP OBJECTIVES: 2.1 4.1 5.2 6.1 7.1 7.2

• Remote Sensing of Organic Volatiles on Mars and Modeling of Cometary Atmospheres

  Using our newly developed analytical routines, Villanueva reported the most comprehensive search for trace species on Mars (Villanueva et al. 2013b, Icarus) and described in detail the chemical taxonomy of comets C/2001 Q4 and C/2002 T7 (de Val-Borro et al. 2013). He expanded our already comprehensive high-resolution spectroscopic database to include billions of spectral lines of ammonia (NH3, Villanueva et al. 2013a), hydrogen cyanide (HCN, Villanueva et al. 2013a, Lippi et al. 2013), hydrogen isocyanide (HNC, Villanueva et al. 2013a), cyanoacetylene (HC3N, Villanueva et al. 2013a), monodeuterated methane (CH3D, Gibb et al. 2013), and methanol (CH3OH, DiSanti et al. 2013). For each species, he developed improved or new fluorescence models using the new spectral models. These permit unprecedented improvement in models of absorption spectra in planetary atmospheres (Earth, Mars), and in computing fluorescence cascades for emission spectra of cometary gases pumped by solar radiation. Villanueva utilized these new models in analyzing spectra of comets that enabled record observations of CO in comet 29P/Schwassmann-Wachmann-1 (see report by Paganini), revealed the unusual organic composition of comet 2P/Encke (see report by Mumma), developed new fluorescence models for the ν2 band of methanol and for the ν3 band of CH3D in comets (see reports by DiSanti and by Bonev), and discovered two modes of water release in comet 103P/Hartley-2 (see report by Bonev).

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1

• Task 3.5.1: Titan as a Prebiotic Chemical System

  Six years ago, NASA sponsored a National Academies report that asked whether life might exist in environments outside of the traditional habitable zone, where “weird” genetic molecules, metabolic processes, and bio‐structures might avoid the water‐based biochemistry that is found across the terran biosphere. In pursuit of this “big picture” question, we turned to Titan, which has exotic solvents both on its surface (methane‐hydrocarbon) and sub‐surface (perhaps super‐cooled ammonia‐rich water). This work sought genetic molecules that might support Darwinian evolution in both environments, including non‐ionic polyether molecules in the first and biopolymers linked by exotic oxyanions (such as phosphite, arsenate, arsenite, germanate) in the second. Further, we asked about the possibility that Titan might inform our understanding of prebiotic chemical processes, including those on “warm Titans”. Our experimental activities found few possibilities for non‐phosphate-based genetics in subsurface aqueous environments, even if they are rich in ammonia at very low temperatures. Further, we showed that polyethers are insufficiently soluble in hydrocarbons at very low temperatures, such as the 90‐100 K found on Titan’s surface. However, we did show that “warm Titans” could exploit propane as a biosolvent for certain of these “weird” alternative genetic biopolymers; propane has a huge liquid range (far larger than water). Further, we integrated this work with other work that allows reduced molecules to appear as precursors for more standard genetic biomolecules, especially through interaction with various mineral species.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 4.1 4.2 5.3 6.2 7.1 7.2

• Preparation of Review Articles

  We prepared a number of astrobiologically-related review articles during the reporting period.

  ROADMAP OBJECTIVES: 4.1 7.1

• Taphonomy, Curiosity and Missions to Mars

  MIT team members are actively involved in both the continuing MER and new MSL missions to Mars. Team members are also collaborating on research designed to provide ground truth for remotely sensed clay mineral identifications on Mars, exploring, as well, the relationship between clay mineralogy and organic carbon preservation in sedimentary rocks. For example, our team has been exploring the use of reflectance spectroscopy, which is a rapid, non-destructive technique, for assessing the presence and abundance of organic materials preserved in ancient rocks. Sumner chairs the Gale Mapping Working Group, which is producing geomorphic and geologic maps of the landing area and lower slopes of Mt. Sharp in Gale Crater. This map is being used for long-term planning of science campaigns for Curiosity as well as to put observations into a regional context.

  ROADMAP OBJECTIVES: 2.1 4.1 4.2 6.1 7.1

• Project 4A: Better, Faster, Smaller Fe Isotope Analysis on Iron Oxides and Sulfides by Femtosecond Laser Ablation: Aerosol Characterization and the Influence of Ablation Cells

  New methods are being developed for in situ stable isotope analysis that increase the precision and/or decrease the volume sampled during the analysis. These improvements allow one to identify isotopic anomalies with increasing spatial resolution. We have focused on improving the ablation cell and mass spectrometer electronics to increase the spatial resolution of Fe isotope studies on iron oxides and sulfides whilst maintaining an external precision of +0.2 ‰ in 56Fe/54Fe using femtosecond Laser Ablation (fs-LA) with isotopic analysis by MC-ICP-MS (Micromass “IsoProbe”). These improvements have allowed us to decrease the volume needed for an Fe isotope analysis to ~600μm3 with an external precision of 0.2 ‰ in 56Fe/54Fe (for a typical analysis the laser beam is rastered over an area of 20 by 15 μm). Compared to previous LA Fe isotope studies the volume used for an analysis in an order of magnitude smaller and is similar to Fe isotope studies that have been done by ion microprobe.

  ROADMAP OBJECTIVES: 1.1 2.1 7.1 7.2

• Undergraduate Research Associates in Astrobiology (URAA)

  2013 featured the Tenth URAA offering (Undergraduate Research Associates in Astrobiology), a ten-week residential research program at the Goddard Center for Astrobiology (GCA) (http://astrobiology.gsfc.nasa.gov/education.html). Competition was very keen, with an oversubscription ratio of 3.0. Students applied from over 19 colleges and universities in the United States, and 6 Associates from 6 institutions were selected. Each Associate carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse laboratories and gaining a broader view of astrobiology as a whole. At summer’s end, each Associate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 6.2 7.1

• The Astrobiology Walk

  The Goddard Center for Astrobiology (GCA) has completed the development and installation of a permanent outdoor exhibit at the Goddard Space Flight Center (GSFC) Visitor Center as a major public outreach effort. The “Astrobiology Walk” is designed to showcase the latest scientific discoveries from the GCA research theme “Search for the Origin and Evolution of Organics” in the context of a timeline for the evolution of the Universe and the Solar System. The exhibit consists of ten outdoor stations situated on the circular pathway around the Visi-tor Center’s “Rocket Garden”, each with a memorable iconic 3D object to convey the main scientific message. QR codes link each placard to web sites relevant to that topic.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 4.1 4.3 7.1 7.2

• Undergraduate Research Associates in Astrobiology (URAA)

  2013 featured the Tenth URAA offering (Undergraduate Research Associates in Astrobiolo-gy), a ten-week residential research program at the Goddard Center for Astrobiology (GCA) (http://astrobiology.gsfc.nasa.gov/education.html). Competition was very keen, with an oversubscription ratio of 3.0. Students applied from over 19 colleges and universities in the United States, and 6 Associates from 6 institutions were selected. Each Associate carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse la-boratories and gaining a broader view of astrobiology as a whole. At summer’s end, each As-sociate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 6.2 7.1