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Project Reports

• Project 1A: Ground Control Experiments for the OREOcube Mission

  The OREOcube (ORganics Exposure in Orbit cube) experiment has been designed to study the effects of solar and cosmic radiation on astrobiology relevant organics when associated with mineral surfaces. The goal of this project is to investigate the (photo)chemical evolution and processing of organic matter in simulated proto-planetary and planetary microenvironments in the laboratory and in space. Testing the photostabitity and evolution of organics in actual space environments on the International Space Station (ISS) provides a powerful tool to study the combined impact of several relevant parameters (e.g., ultraviolet and comic radiation, microgravity) simultaneously. The OREOcube capability to measure in-situ changes of samples exposed to space radiation using an UV-visible-NIR spectrometer as a function of time in Low Earth Orbit will confer significant advantages relative to more basic ISS exposure facilities for which sample measurements are made on Earth prior to and at the end of a space mission. The innovative aspect of this OREOcube experiments is the capability of in-situ monitoring of flight samples, which has not yet been achieved on the ISS. A comparison of measurements performed with OREOcube with recent LEO data (EXPOSE-E, EXPOSE-R, O/OREOS Sat) and ground-based laboratory data will reveal how those combined data from different exposure facilities can be effectively used to investigate the evolution of organic matter in space.

  ROADMAP OBJECTIVES: 3.1

• Life Underground

  Our multi-disciplinary team from the University of Southern California, California Institute of Technology, Jet Propulsion Lab, Desert Research Institute, Rensselaer Polytechnic Institute, and Northwestern University is developing and employing field, laboratory, and modeling approaches aimed at detecting and characterizing microbial life in the subsurface—the intraterrestrials. We posit that if life exists, or ever existed, on Mars or other planetary body in our solar system, evidence thereof would most likely be found in the subsurface. This study takes advantage of unique opportunities to explore the subsurface ecosystems on Earth through boreholes, mine shafts, sediment coring, marine vents and seeps, and deeply-sourced springs. Access to the subsurface—both continental and marine—and broad characterization of the rocks, fluids, and microbial inhabitants is central to this study. Our focused research themes require subsurface samples for laboratory and in situ experiments. Specifically, we are carrying out in situ life detection, culturing and isolation of heretofore unknown intraterrestrial archaea and bacteria using numerous novel and traditional techniques, and incorporating new and existing data into regional and global metabolic energy models.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.2 3.3 4.1 5.1 5.2 5.3 6.1 6.2 7.2

• Inv 1 – Geochemical Reactor: Energy Production at Water-Rock Interfaces

  INV 1 examines water-rock interactions in the lab and in the field, to characterize the geochemical gradients that could be present at water-rock interfaces on Earth and other worlds, taking into account different ocean and crustal chemistries. We have fully investigated serpentinization as the most likely of all possible environments for life’s emergence on Earth as well as other water-rich worlds – a key goal for astrobiology as stated in the NASA Astrobiology Roadmap 2008. (Russell, 2015). Serpentinization is now recognized as fundamental to delivering the appropriate chemical disequilibria at the emergence of life. And the fact that this process is likely inevitable on any icy, wet and rocky planet makes its study fundamental to emergence of life, habitability and habitancy. Nevertheless, notwithstanding the thermodynamic drives to CO₂ reduction during the process, great uncertainty exists over just what kind of organic molecules (if any) are delivered to the submarine springs and consequential precipitate mounds. In attempts to clarify what these might be we have undertaken thermodynamic modelling and experimental investigations of the serpentinization process.

  ROADMAP OBJECTIVES: 2.2 3.1 3.2 3.3 3.4 4.1

• Modeling and Observation of Disks Project

  The broader goal of this NAI team is to understand and follow the evolution of complex, prebiotic organic molecules from the interstellar medium to their incorporation into planets. This Project’s work focuses on chemical evolution in the protoplanetary disk stage of planetary system formation. Disk matter provides the raw material for planet formation and its composition is thus expected to have a direct bearing on the composition of planets and eventually, the origin of life on them. We study disk chemical evolution via a two-pronged approach: (i) theoretical modeling of disk physical structure and its chemistry in time and the transport of matter in the disk as it evolves, and (ii) constructing synthetic line and continuum spectra and images of gas and dust in disks to compare with observational data from ground and space-based telescopes. New chemical networks that incorporate results from the Laboratory and Quantum Calculation Projects are developed and disk modeling results compared with observations to infer conditions under which the solar system and exoplanets formed.

  ROADMAP OBJECTIVES: 1.1 3.1 3.2

• Analysis of Prebiotic Organic Compounds in Astrobiologically Relevant Samples

  The Astrobiology Analytical Laboratory (AAL) of the GCA is dedicated to the study of organic compounds derived from past and future sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development. This year, we continued our work analyzing the organic content of carbonaceous chondrites, including analyses of amino acids, aliphatic amines, aldehydes and ketones. We investigated model systems for potentially relevant prebiotic chemistry. We supported the Biomolecule Sequencer project for evaluating DNA-analysis in microgravity environments by flying a MinIon device on the International Space Station. We continued to support development of protocols for a liquid chromatograph-mass spectrometer aimed at in situ analyses of amino acids and chirality on airless bodies, including asteroids and outer-planet icy moons (e.g., Enceladus and Europa). We participated in numerous public outreach and education events. We continued our participation in the OSIRIS-REx asteroid sample return mission and provided support for the Sample Analysis at Mars instrument of NASA’s Mars rover Curiosity.

  ROADMAP OBJECTIVES: 2.1 3.1

• Inv 2 – From Geochemistry to Biochemistry

  INV 2 focuses on experimentally simulating the geological disequilibrium in hydrothermal systems, and determining the role of minerals in harnessing these gradients toward the emergence of metabolism. Biology utilizes metals (to speed up reactions) and “engines” (such as electron bifurcators, to couple endergonic and exergonic reactions); these components in modern metabolism strongly resemble specific minerals found in hydrothermal environments. We focus on simulating these primordial geological components and processes that might have led to the beginning of metabolism in a seafloor system on a wet rocky planet.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 4.1 7.1

• Project 2: Cells as Engines and the Serpentinization Hypothesis for the Origin of Life

  All life is, and must be, “powered” since all of its most essential and distinguishing processes have to be driven “up-hill” against their natural thermodynamic direction. By the 2nd law of thermodynamics, however, a process can only be made to proceed up-hill by being mechanistically linked, via a molecular device functioning as an engine, to another, more powerful, process that is moving in its natural, down-hill direction. On fundamental principles, we argue, such engine-mediated conversion activities must also have been operating at, and indeed have been the cause of, life’s emergence. But what then were life’s birthing engines, what sources of power drove them, what did they need to produce, and how did they arise in an entirely lifeless world? Promising potential answers to these and other questions related to the emergence of life are provided by the Alkaline Hydrothermal Vent/serpentinization (“AHV”) hypothesis, whose original propounder and lead proponent, Dr. Michael Russell of JPL, is a co-investigator on this project. The goal of the project is specifically to clarify the essential mechanistic modus operandi of all molecular engines that power life, and to see how the most fundamental and prerequisite of these could have arisen, and operated, in the structures and flows produced by the serpentinization process. Importantly, candidate answers to these questions can be put to definitive laboratory tests.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 3.2 3.3 3.4

• Inv 3 – Planetary Disequilibria: Characterizing Ocean Worlds and Implications for Habitability

  INV 3 looks at how, where, and for how long might
disequilibria exist in icy worlds, and what that may imply in terms of
habitability. A major interest for this work is how ocean composition affects habitability. We are investigating chemistry behaves under conditions of pressure, temperature, and composition not found on Earth. Our simulations of deep ocean world chemistry couple with models for ocean dynamics, ocean ice interaction, and tectonics within the ice. We are examining each of these, how they interact, and how they relate to what future missions may discover. Members of our team are involved in missions to Mars, Jupiter’s moon Europa, Saturn, and Pluto. We are also involved in studies of exoplanets, and are working to understand how ocean worlds like Ganymede and Europa might provide analogues for more distant watery super-earths.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 4.2 6.2 7.1 7.2

• Evolution of Protoplanetary Disks and Preparations for Future Observations of Habitable Worlds

  The evolution of protoplanetary disks tells the story of the birth of planets and the formation of habitable environments. Microscopic interstellar materials are built up into larger and larger bodies, eventually forming planetesimals that are the building blocks of terrestrial planets and their atmospheres. With the advent of ALMA and continuing use of the Hubble Space Telescope, we are poised to break open the study of young exo-planetesimals, probing their organic content with detailed observations comparable to those obtained for Solar System bodies. Furthermore, studies of planetesimal debris around nearby mature stars are paving the way for future NASA missions to directly observe potentially habitable exoplanets.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 7.2

• Subsurface Serpentinization Processes and In-Situ Microbial Life in Oman

  The Rock-Powered Life team has initiated several field-based efforts in Oman focused on characterizing the geochemistry and microbial community structure and activity within massive exposures of peridotites undergoing low-temperature serpentinization. In this project, we are using deep wells drilled hundreds of meters into peridotite catchments to access waters stored in the deep subsurface, and to capture the mineralogical and biological processes that give rise to hyperalkaline fluids rich in dissolved H₂ and CH₄. In particular we extract biomass from the fluids for genetic sequencing in order to identify the types of life that can live within the extreme conditions of low energy and carbon availability, and to infer the metabolisms that sustain in-situ life activity. These analyses are paired with mineralogical analyses of the subsurface rocks and isotopic analyses of the dissolved gases in order to quantify the water/rock reactions occurring in the modern system that give rise to energy transfer from the rocks to living ecosystems.

  ROADMAP OBJECTIVES: 3.1 4.1 5.3 7.2

• Exploring the Evolution of the Water and Organic Reservoirs in the Solar System

  This project investigates the evolution and stability of water and organic reservoirs in our Solar System, with particular emphasis on the characterization of the current and ancient habitability of planet Mars. We employ extremely powerful observatories (e.g., ALMA, Keck, VLT, future JWST) to acquire high spatial and spectral resolution maps of the isotopic and organic signatures on several bodies in the Solar System. These maps allow us to investigate the stability and evolution of their atmospheres, while localized plumes can be used to identify regions of active release. In this reporting period, we emphasized three areas:

  1. We advanced our pioneering work on characterizing the evolution of water on Mars, by developing a new observational plan that combines the power of ALMA, of Keck and of MAVEN to obtain maps of the water D/H signatures on Mars.

  2. We identified previously unknown chemical processes affecting singlet-O₂ and odd-oxygen on Mars, which may be indicative of a much more active photochemical cycle (with the possible intervention of heterogeneous processes).

  3. We provided science leadership in the investigation of Mars with the James Webb Space Telescope (JWST), and established a variety of observing modes and scientific opportunities.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1

• RPL and Expedition 357: Serpentinization and Life at the Atlantis Massif

  Circulating hydrothermal fluids associated with mid-ocean ridges represent some of the most prominent examples of the intersection between chemical energy and the biosphere. The Lost City Hydrothermal Field, which sits atop the Atlantis Massif near the Mid Atlantic Ridge hosts a microbial ecosystem which feeds off the products of serpentinization. IODP Expedition 357, which sailed in Fall 2015, obtained rock cores and fluids from the Atlantis Massif, which are being used for the coordinated investigation of serpentinization processes and life. Lost City is known to sustain abiogenic organosynthesis reactions and as such has been suggested to be an analogue to prebiotic early Earth environments and potential extraterrestrial habitats.

  ROADMAP OBJECTIVES: 3.1 3.4 5.1 5.2 5.3 7.2

• Project 7: Mining Archaeal Genomes for Signatures of Early Life: Comparison of Metabolic Genes in Methanogens

  Methanogens represent the largest diversity among the archaea and have the unique ability to generate methane from simple compounds such as carbon dioxide, acetate and methylamines which were common in the anaerobic environments of early Earth and perhaps Mars. Methane biosynthesis also requires the presence/uptake of important ions such as sulfates, sulfides, carbonates, phosphates, and various light metal ions. In this project, we are attempting to analyze the evolution of the methanogens’ central cellular functions of translation, transcription, replication, and metabolism. To accomplish this, we are constructing the metabolic and regulatory networks of Methanosarcina acetivorans, the most complex methanogen known, and using these models to establish a framework for studying the evolution of methanogens. Results will be tested through microfluidic studies using varying carbon and ion sources.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 3.3 3.4 4.1 4.2 5.1 5.2 5.3 6.1 6.2 7.1

• Interstellar and Nebular Chemistry: Theory and Observations

  We continue to undertake theoretical and observational studies pertaining to the origin and evolution of organics in Planetary Systems, including the Solar System. In this performance period, we have focused on studies aimed at understanding the origin and processing of organics in the earliest evolutionary phases of stars like the Sun. These include formation pathways and related isotopic fractionation effects.

  We have continued observational programs designed to explore the chemical composition of comets and establishing their potential for delivering prebiotic organic materials and water to the young Earth and other planets. State-of-the-art international facilities are being employed to conduct multi-wavelength simultaneous studies of comets in order to gain more accurate abundances, distributions, temperatures, and other physical parameters of various cometary species. We are also leading an international collaboration to study the organic composition of Titan with the Atacama Large Millimeter Array (ALMA).

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 7.1 7.2

• Habitable Planet Formation and Orbital Dynamical Effects on Planetary Habitability

  This task explores how habitable planets form and how their orbits evolve with time. Terrestrial planet formation involves colliding rocks in a thin gaseous disk surrounding a newborn star and VPL’s modeling efforts simulate the orbital and collisional evolution of a few to millions of small bodies to determine the composition, mass, and orbital parameters of planets that ultimately reach the habitable zone. After formation, gravitational interactions with the star and planet can induce short- and long-term changes in orbital properties that can change amount of energy available for the climate and to illuminate the planetary surface. The VPL simulates these effects in known and hypothetical planetary systems in order to determine the range of variations that permit planetary habitability.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 4.3

• Laboratory Investigations Into Chemical Evolution in Icy Solids: Mars, Carbonaceous Meteorites, and ISM

  The goal of this project is to investigate chemical and physical changes and properties of molecules in low-temperature environments, such as found in interstellar space and the outer regions of the Solar System. Some of the molecules studied have been detected in meteorites and samples returned from NASA missions.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1

• NAI ARC Communications

  The ARC NAI Team interacts with a number of institutions that fall outside the NAI proper. These include universities and other domestic and international organizations, chief of which are Langston University, the Chickasaw and Choctaw Nations, and the Dutch Astrochemistry Network, which is part of the Netherlands Organization for Scientific Research (NWO).

  ROADMAP OBJECTIVES: 3.1 3.2 3.4

• NNX15AT33A Origin and Evolution of Organics and Water in Planetary Systems

  Research by the Blake group (CalTech) supported by the NAI has centered on a joint laboratory and observational program, designed with the participation of Goddard node scientists, that aims to investigate the chemistry of water and simple organics in the protoplanetary disk analogs of the early solar nebula, in comets, and in the atmospheres of extrasolar planets. The laboratory work has involved the creation of novel high bandwidth instruments from the microwave to the THz regime that can probe both gaseous and condensed phase (liquid and solid) materials. Particular emphasis has been placed on the study of small chiral (that is, ‘handed’) organic species, with a view toward establishing whether the homochirality exhibited on the Earth is stochastically or deterministically derived. We combine the laboratory studies with astronomical observations at radio (VLA, GBT, ALMA), far-infrared (SOFIA, Herschel archival data), and infrared (Keck/VLT, Spitzer archival data) wavelengths. A recent highlight is the first detection of a chiral species toward the Galactic Center, as is described in this report

  ROADMAP OBJECTIVES: 1.1 1.2 3.1

• Laboratory Studies

  The Laboratory Studies project uses a variety of cryo-vacuum systems to study the physical and chemical properties of astrophysically relevant materials to better understand the extent to which these materials can be converted in more complex organic materials of astrophysical and astrobiological importance. We concentrate on mimicking conditions found in astrophysically relevant environments involving low temperatures, low pressures, and high radiation fields. The main processes we explore are the photolytic processing of mixed molecular ices and organics and chemistry that occurs at gas-solid interfaces.

  ROADMAP OBJECTIVES: 3.1 3.2 3.4

• Serial Measurements of the Volatile Composition of Comet D/2012 S1 (ISON) between 1.2 and 0.34 AU from the Sun

  The composition of ices and rocky material in cometary nuclei is central to understanding their origins, and to assessing their possible roles in delivering water and prebiotic organic compounds to the young Earth. For most comets, measurements of primary volatiles (ices contained in the cometary nucleus) exist for only a single date or for very few dates, questioning whether such ‘momentary’ measurements represent the bulk content of the nucleus. The early discovery of the dynamically new, sun-grazing comet C/2012 S1 (ISON) was extremely rare in that it permitted measurements of the abundances of sublimed ices over a large range of heliocentric distance (R_h). As part of a world-wide observing campaign, world-class astronomical observatories provided large amounts of observing time dedicated to studying Comet ISON. Using high-resolution infrared spectroscopy at Keck-2 and the NASA-IRTF, the GCA Team measured production rates for H₂O and eight trace gases (CO, C₂H₆, CH₄, CH₃OH, NH₃, H₂CO, HCN, C₂H₂) on ten pre-perihelion dates that spanned heliocentric distances ranging from 1.21 to 0.34 AU. This project addressed the evolution in molecular production and composition as the comet approached the Sun. GCA members also investigated the spatial distribution of H₂O in the near-nucleus coma to identify modes of water release and of heat injection by release from icy grains, and they conducted a sensitive search for HDO to test the potential delivery of Earth’s oceans by such comets.

  ROADMAP OBJECTIVES: 3.1 3.2

• Surface Mediated Reactions in the Primitive Solar Nebula

  Hydrogen, carbon monoxide and nitrogen gases are abundant in the primitive solar nebula, as are silicate dust and metallic grains. These gases can react on such grain surfaces to produce an abundance of carbon-bearing products that include volatile hydrocarbons, amines, alcohols, aldehydes and acids as well as more complex, less volatile species such as carbon nanotubes. Refractory carbonaceous deposits catalyze additional surface reactions. Nebular environments span a large range in time, temperature, pressure, catalyst composition and secondary reactions. We are working to understand the rates and products of such reactions that could occur in nebular environments.

  ROADMAP OBJECTIVES: 1.1 3.1

• Undergraduate Research Associates in Astrobiology (URAA)

  2015 saw the twelfth session of our summer program for talented science students (Under-graduate Research Associates in Astrobiology), a ten-week residential research program tenured at Goddard Space Flight Center and the University of Maryland, College Park (http://astrobiology.gsfc.nasa.gov/education.html). Competition was again very keen, with an over-subscription ratio of 4.7. Students applied from over 19 Colleges and Universities in the United States, and 4 Interns from 4 institutions were selected. Each Intern 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 1.2 2.1 2.2 3.1 6.2 7.1

• Physiology of Microbial Populations From W/R Hosted Ecosystems

  Microbial communities supported by chemical energy (chemotrophic communties) released through water / rock interactions are widespread in contemporary Earth environments, including the subsurface where light is excluded and in surface environments where physical or chemical conditions preclude photosynthetic metabolisms. Chemotrophic microorganisms are key targets of astrobiological investigation due to the strong likelihood that they predate photosynthetic metabolisms and because they can be physiologically tested to define the habitable limits for life on Earth, including those associated with extremes of temperature, pH, salinity, and energy availability. Research by RPL scientists is focused on identifying and characterizing the physiological strategies or mechanisms that allow life to persist under extreme conditions at the habitable limits. By combining this information with phylogenetic approaches, we aim to determine how and when these mechanisms evolved and what role they played in the diversification of early life. As such, this research effort is highly interdisciplinary and employs both traditional (e.g., activity assays, cultivation) and contemporary (genomics, transcriptomics, metabolomics) microbiological approaches in combination with geochemical approaches. In addition, RPL investigators are studying the evolution of these communities to hone in on the nature of key physiological processes (e.g., central carbon metabolism, nitrogen metabolism, and iron-sulfur metabolism) in chemotrophs prior to the onset of photosynthetic metabolisms. Field-based RPL investigations of microbial physiology in water/rock ecosystems to date have focused on populations inhabiting subglacial environments (cold-adaptation), hot springs (adaptation to acidity, high temperature), and subsurface peridotite environments (adapation to energy stress, nutrient stress, alkalinity).

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 4.1 5.1 5.2 5.3