2014 Annual Science Report

Astrobiology Roadmap Objective 3.2 Reports Reporting  |  SEP 2013 – DEC 2014

Project Reports

  • 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: 2.2 3.1 3.2
  • Co-Crystals on the Surface of Titan

    We have discovered that benzene and ethane form a co-crystalline inclusion compound at Titan surface temperatures and pressures. Co-crystals of other organic compounds could be common on Titan’s surface. These results can help explain the release of ethane observed at the Huygens landing site, and point to a new type of surface material that may have significant impact on Titan surface chemistry and geology.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2
  • Advancing Techniques for in Situ Analysis of Complex Organics: Laser Mass Spectrometry of Planetary Materials

    In this final reporting period under CAN-5, we extended the development of protocols for laser mass spectrometry (MS) for analysis of complex, nonvolatile organic molecules from the progress made last year. In particular the major area of focus was in (1) the use of tunable laser wavelengths for desorption in two-step laser MS (L2MS), and (2) the use of tandem mass spectrometry (MS/MS) for in situ molecular structure analysis. Each of these protocols has been investigated during the course of the CAN-5 project, jointly supported by NAI and instrument development (PIDDP, MatISSE) and flight (MOMA) programs. The unique aspect of these efforts is their implementation and evaluation using truly miniature, flight-like instrumentation, to optimize the benefit to real mission science.

    ROADMAP OBJECTIVES: 2.1 2.2 3.2 7.1
  • Astrobiology of Icy Worlds

    Our goal in the Astrobiology of the Icy Worlds Investigation is to advance our understanding of the role of ice in the broad context of astrobiology through a combined laboratory, numerical, analytical, and field investigations. Icy Worlds team pursues this goal through four major investigations namely, the habitability, survivability, and detectability of life of icy worlds coupled with “Path to Flight” Technology demonstrations. A search for life linked to the search for water should naturally “follow the ice”. Can life emerge and thrive in a cold, lightless world beneath hundreds of kilometers of ice? And if so, do the icy shells hold clues to life in the subsurface? These questions are the primary motivation of our science investigations

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 4.1 5.1 5.2 5.3 6.2 7.1
  • Project 1: Dynamics of Self-Programming Systems

    This project is a theoretical attempt to understand how evolution can arise from inanimate physical systems. The key idea is that matter can organize into structures that not only replicate and carry information, but are able to program and reprogram themselves functionally. We have already been able to construct simple computer programs that can increase their complexity in an open-ended way, but in this grant period we have been building a mathematical formulation of how this arises using recursive function theory. We have also been trying to develop cellular automata meta-programming pairs that can co-evolve complexity.

    ROADMAP OBJECTIVES: 3.2 4.1 4.2 5.3 6.2
  • Project 2: Processing of Precometary Ices in the Early Solar System

    The discovery of numerous planetary systems still in the process of formation gives us a unique opportunity to glimpse how our own solar system may have formed 4.6 billion years ago. Our goal is to test the hypothesis that the building blocks of life were synthesized in space and delivered to the early Earth by comets and asteroids. We use computers to simulate shock waves and other processes that energize the gas and dust in proto-planetary disks and drive physical and chemical processes that would not otherwise occur. Our work seeks specifically to determine (i) whether asteroids and comets were heated to temperatures that favor prebiotic chemistry; and (ii) whether the requisite heating mechanisms operate in other planetary systems forming today.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Development of Direct Sampling Methodology for Analysis of Complex Organic Mixtures on Titan’s Surface

    Photochemistry in Titan’s dense atmosphere generates a complex mixture of organic molecules that have been deposited on Titan’s surface over time. Requiring no sample pretreatment or handling, the technique of direct analysis in real time (DART), combined with an ion trap mass spectrometer having MS/MS capability, is shown to be an enabling experimental methodology to vaporize, ionize, and structurally characterize organic components of this mixture. A key important development is the use of temperature programmed desorption, accomplished by heating of the probe gas, to examine complex mixtures of organics with a wide range of volatility (polypropylene glycol and tar samples from a petroleum seep). Of particular relevance to astrobiology, this methodology is employed to compare Titan simulants produced in a pulsed discharge from gas mixtures designed to probe mechanistic pathways leading to high molecular weight products.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2
  • 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 2.1 3.1 3.2 3.3 3.4
  • Investigation of Electron-Molecule Chemistry and Micrometeorite Induced Reactions on Titan’s Surface

    Low-energy electron-beam irradiation and dissociative electron attachment (DEA) experiments were performed on nitrogen-containing organic condensates as a model for cosmic-ray induced polymerization processes and charging events that can occur within Titan’s atmosphere and on Titan’s organic-rich surface. In addition, detailed analysis of meteorite surfaces were analyzed with an emphasis of understanding the corrosion of schreibersite and the role this may play in the formation of phosphorylated pre-biotic molecules.

    ROADMAP OBJECTIVES: 3.1 3.2 7.1
  • Project 3: The Origin of Homochirality

    A universal aspect of living systems on Earth is their homochirality: Life uses dextrorotary sugars and levorotary amino acids. The reasons for this are hotly debated and not close to being settled. However, the leading idea is that autocatalytic reactions grew exponentially fast at the origin of life, and whatever chiral symmetry breaking was accidentally present became amplified subsequently. We are calculating the way in which this can take place using statistical mechanics, and also trying to see how a uniform homochirality could be stable to spatial fluctuations.

    ROADMAP OBJECTIVES: 3.2 3.4 4.1 4.2 5.1 5.2 7.1 7.2
  • Origins of Functional Proteins and the Early Evolution of Metabolism

    The main goal of this project is to identify critical requirements for the emergence of biological complexity in early habitable environments by examining key steps in the origins and early evolution of functional proteins and metabolic reaction networks. Applying a combination of experimental and theoretical methods, we investigate whether protein functionality can arise from an inventory of polypeptides that might have naturally existed in habitable environments, investigate how primordial proteins could evolve through the diversification of their structure and function and determine how simple proteins could carry out seemingly complex functions that are essential to life. This work offers unique information about the earliest evolution of cellular systems that has not been available from other studies.

    ROADMAP OBJECTIVES: 3.2 3.4
  • Longer Wavelength Photochemistry of Condensates and Aerosols in Titan’s Lower Atmosphere and on the Surface

    This study focuses on the condensed phase photochemistry on Titan. In particular, we focus on understanding longer wavelength photochemistry of solid hydrocarbons so simulate photochemistry that could occur based on the UV penetration through the atmosphere and on the evolution of complex organic species in astrobiologically significant regions on Titan’s surface. Here we investigate the oxygenation chemistry involving the condensed Titan’s organic aerosols with water-ice on Titan’s surface – induced by high energy photons simulating the cosmic ray induced chemistry on Titan’s surface.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3
  • NAI Titan Education and Public Outreach

    Planetariums have a long history of experimentation with audio and visuals to create new multimedia experiences. We report on a series of innovative experiences that began in the Gates Planetarium at the Denver Museum of Nature & Science, combining live performances of music and navigation through scientific visualizations. The Life Out There productions featured a story showcasing astrobiology concepts at scales ranging from galactic to molecular, and told using VJ-ing of immersive visualizations and musical performances from the House Band of the Universe. These hour-long shows were broken into four separate themed musical movements, with an improvisatory mix of music, dome visuals, and spoken science narrative which resulted in no two performances being exactly alike. Post-performance dissemination is continuing via a recorded version of the performance available as a DVD and online streaming video. Written evaluations from visitors who were present at the live shows reveal high satisfaction and subsequent interest in astrobiology topics. Life Out There concerts have been used to inaugurate a new evening program to draw in a younger audience demographic to DMNS, and have been taken on the road to other venues in other cities.

    We continued the development and public presentation of this live digital planetarium show about Titan and Astrobiology. This live lecture planetarium show, entitled “Life Out There” makes use of the digital imaging capabilities of the dome, through the innovative Uniview software, a “real time” virtual simulation of the known universe based on accurate astronomical databases and modeling. The inclusion of live musicians, who serve to introduce each section of the show, helps to attract an audience beyond those who reliably come to space science events at the planetarium, and help to create a relaxing and evocative atmosphere conducive to wonder and learning. With Uniview, we can utilize the SPICE Kernels that spacecraft teams use to describe mission trajectories, and create virtual versions that can be followed along through the simulation. Using 3-D spacecraft models, the public can follow spacecraft missions shown with breathtaking realism within the immersive display. We have a detailed model of the Cassini spacecraft, and we are using the most recently updated SPICE kernels of Cassini, including the many Titan flybys, to show the public the fantastic journey of Cassini and Huygens in exploring Titan. In addition to the live lecturer, a second operator controls the Uniview software, allowing these flybys to be seen from any perspective deemed instructive and/or entertaining. Various Cassini and Huygens image data sets, including camera data, infrared spectrometer data and radar data, are being texture mapped and rendered on the moon’s surface. The atmosphere is visually peeled away, and various visuals are used together with an original script and musical score, both written by E/PO lead David Grinspoon, to explore themes of Titan and Astrobiology for the public. The visual content was directed by Dr. KaChun Yu, Curator of Space Sciences at DMNS, in collaboration with Dr. Grinspoon.

    We developed, tested, evaluated and disseminated a 20-minute stage show for informal science centers to excite and inform visitors about the science and exploration of Titan. The show utilizes a participatory exercise in scientific illustration to engage visitors in the material. Each participant is given a clipboard and pencils, and the facilitator, using a series of Cassini and Huygens images and videos of Titan, leads them through an exercise in which each draws a sketch of a Titan landscape, learning along the way about many aspects of the Titan environment as revealed by modern exploration. The show has now been seen by many thousands of visitors to the Denver Museum of Nature and Science.

    During this last year we focused on disseminating the presentation materials and supporting media, and training materials, including a training DVD for presenters for use at other informal science centers.

    We continued the development and public presentation of a live digital planetarium show about Titan and Astrobiology. This live lecture planetarium show, entitled “Life Out There” makes use of the digital imaging capabilities of the dome, through the innovative Uniview software, a “real time” virtual simulation of the known universe based on accurate astronomical databases and modeling. The inclusion of live musicians, who serve to introduce each section of the show, helps to attract an audience beyond those who reliably come to space science events at the planetarium, and help to create a relaxing and evocative atmosphere conducive to wonder and learning. With Uniview, we can utilize the SPICE Kernels that spacecraft teams use to describe mission trajectories, and create virtual versions that can be followed along through the simulation. Using 3-D spacecraft models, the public can follow spacecraft missions shown with breathtaking realism within the immersive display. We have a detailed model of the Cassini spacecraft, and we are using the most recently updated SPICE kernels of Cassini, including the many Titan flybys, to show the public the fantastic journey of Cassini and Huygens in exploring Titan. In addition to the live lecturer, a second operator controls the Uniview software, allowing these flybys to be seen from any perspective deemed instructive and/or entertaining. Various Cassini and Huygens image data sets, including camera data, infrared spectrometer data and radar data, are being texture mapped and rendered on the moon’s surface. The atmosphere is visually peeled away, and various visuals are used together with an original script and musical score, both written by E/PO lead David Grinspoon, to explore themes of Titan and Astrobiology for the public. The visual content was directed by Dr. KaChun Yu, Curator of Space Sciences at DMNS, in collaboration with Dr. Grinspoon.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2
  • Project 6. Mining Archaeal Genomes for Signatures of Early Life: Comparison of Metabolic Genes in Methanogens

    Methanogenic archaea derive energy from simple starting materials, producing methane and carbon dioxide in the process. The chemical simplicity of the growth substrates and versatility of the organisms in extreme environments provide for a possibility that they could exist on other planets. By characterizing the evolution of methanogens from the most simple to most complex organism as well as their growth characteristics under controlled environments, we hope to address the question as to whether they could exist on planets such as Mars, where bursts of methane have been seen, yet no source has yet been identified.

    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 7.2
  • Project 6: Prebiotic Chemical Catalysis on Early Earth and Mars

    The “RNA World” hypothesis is the current paradigm for the origins of terrestrial life. Our research is aimed at testing a key component of this paradigm: the efficiency with which RNA molecules form and grow under realistic conditions. We are studying abiotic production and polymerization of RNA by catalysis on montmorillonite clays. The catalytic efficiency of different montmorillonites are determined and compared, with the goal of determining which properties distinguish good catalysts from poor catalysts. We are also investigating the origin of montmorillonites, to test their probable availability on the early Earth and Mars, and the nature of catalytic activity that could have led to chiral selectivity on Earth.

    ROADMAP OBJECTIVES: 3.1 3.2
  • Titan as a Prebiotic Chemical System – Benner

    In 2007, NASA sponsored a committed of the National Academies of Science to explore whether life might exist in environments outside of the traditional habitable zone, defined as positions in a solar system where liquid surface water might be found. Alternative solvents which have analogous “habitable zones” farther away from their star include hydrocarbons, ammonia, and dinitrogen. The core question asked whether life having genetic biopolymers might exist in these solvents, which are in many cases (including methane) characterized by the need for “cold” (temperatures < 100K in the case of methane).

    These “weird” solvents would require “weird” genetic molecules, “weird” metabolic processes, and “weird” bio-structures. 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.

    In the current year, we completed our studies that identified biopolymers that might work in hydrocarbon solvents. These studies have essentially ruled out biological processes in true cryosolvents. However, a series of hydrocarbons containing different numbers of carbon atoms (one, two, three, and four, for example, in methane, ethane, propane, and butane) cease to be cryosolvents as their chain lengths increase. These might be found on “warm Titans”. Further, they might exist deep in Titan’s hydrocarbon oceans, where heating from below would lead to warm hydrocarbon oceans.

    These studies showed that polyethers are insufficiently soluble in hydrocarbons at very low temperatures, such as the 90-100 K found on Titan’s surface where methane is a liquid at ambient pressures. However, we did show that “warm Titans” could exploit propane (and, of course, higher hydrocarbons) 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 mineralogy-based work that allows reduced molecules to appear as precursors for less “weird” genetic biomolecules, especially through interaction with various mineral species, including borates, molybdates, and sulfates.

    ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 3.4 4.1 5.3 6.2 7.1 7.2
  • Project 7: Microenvironmental Influences on Prebiotic Synthesis

    Before biotic, i.e., “biologically-derived” pathways for the formation of essential biological molecules such as RNA, DNA and proteins could commence, abiotic pathways were needed to form the molecules that were the basis for the earliest life. Much research has been done on possible non-biological routes to synthesis of RNA, thought by many to be the best candidate or model for the emergence of life. Our work focuses on possible physicochemical microenvironments and processes on early earth that could have influenced and even directed or templated the formation of RNA or its predecessors.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4
  • Fischer-Tropsch-Type Reactions in the Solar Nebula

    Fischer-Tropsch-Type (FTT) reactions can form complex hydrocarbons via surface-mediated reactions using simple gases (CO, N2, and H2) on almost any grain surface and are currently being studied in relation to the early Solar Nebula. Several theories exist as to how hydrocarbons are formed in the early Solar System but the compelling nature of this type of reaction is that it is passive and generates a wide variety of complex hydrocarbons using commonly available components (gases/grains) without invoking a complex set of conditions for formation.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2
  • Early Animals: The Role of Biosignatures in Illuminating Homonin Diet

    Work conducted by Ainara Sistiaga, a student visitor from the University of La Laguna, Tenerife, Spain, aimed to evaluate the biomarker methodologies we typically apply to modern and ancient sediments to the issues surrounding the evolution of homo sapiens. Gas chromatography-mass spectrometry data on samples from El Salt (Spain), a Middle Palaeolithic site dating to ca. 50,000 yr. BP, represents the oldest positive identification of human faecal matter. We showed that Neanderthals, like anatomically modern humans, have a high rate of conversion of cholesterol to coprostanol related to the presence of specific gut flora. Analysis of five sediment samples from different occupation floors suggests that Neanderthals predominantly consumed meat, as indicated by high coprostanol proportions, but also had significant plant intake, as shown by the presence of 5β-stigmastanol.

    ROADMAP OBJECTIVES: 3.2 4.2
  • Titan as a Prebiotic System Activity Report

    We are calculating how much material, over time, is ejected from geysers on the moon Enceladus and ends up on the moon Titan, and how this material may be important for pre-biological chemistry on Titan.

    ROADMAP OBJECTIVES: 2.2 3.1 3.2 3.3
  • The Long Wavelength Limit of Oxygenic Photosynthesis

    Oxygenic photosynthesis (OP) produces the strongest biosignatures at the planetary scale on Earth: atmospheric oxygen and the spectral reflectance of vegetation. Both are controlled by the properties of chlorophyll a (Chl a), its ability to perform the water-splitting to produce oxygen, and its spectral absorbance that is limited to red and shorter wavelength photons. We seek to answer what is the long wavelength limit at which OP might remain viable, and how. This would clarify whether and how to look for OP adapted to the light from stars redder than our Sun.

    Previously under this project, with other co-investigators we spectrally quantified the thermodynamic efficiency of photon energy use in the chlorophyll d utilizing cyanobacterium, Acaryochloris marina str. MBIC11017, determining that it is more efficient than a Chl a cyanobacterium. The current focus of the project is aimed at understanding the adaptations of far-red/near-infrared (NIR) oxygenic photosynthetic organisms in general: what is their ecological niche where they are competitive against chlorophyll a organisms in nature, and what energetic shifts have been made in their photosynthetic reactions centers to enable their use of far-red/NIR photons. Field sampling and measurements are being conducted to isolate new strains of far-red utilizing oxygenic photosynthetic organisms, to quantify the spectral and temporal light regime in which they and previously discovered strains live in nature, and use these light measurements to drive kinetic models of photon energy use to ascertain light thresholds of survival.

    ROADMAP OBJECTIVES: 3.2 4.2 5.1 5.3 6.2 7.2
  • Project 13: Experimental Determination of the Existence of the Darwinian Transition

    Life on our planet can be divided into three domains: Archaea, Bacteria and Eukarya. While some genes may be shared among the domains of life, others especially those involved in information processing namely DNA replication, transcription and translation are often unique to a particular domain. It has, therefore, been proposed that the molecular machineries that carry out these processes (replication, transcription and translation) have crossed a so-called Darwinian threshold where the molecular machineries have become gelled and therefore intolerant of new components. This project is examining the Darwinian threshold hypothesis by testing the interchangeability of the components of the DNA replication machinery across the domains of life. Further experiments will examine the capacity of biomolecules involved in translation and transcription to substitute for their counterparts across the domains of life.

    ROADMAP OBJECTIVES: 3.2 3.4 4.2 5.3
  • Remote Sensing of Organic Volatiles on Mars and Modeling of Cometary Atmospheres

    During this period, Dr. Villanueva mainly worked on processing high-resolution (spectral and spatial) data of Mars acquired in January/2014 and in the observational campaigns of 2008, 2009 and 2010, using the recently developed new analytical and modeling capabilities. Unprecedented maps of the D/H ratio in water were extracted from these data, and a paper was recently accepted by Science (see below). In addition, he participated in several international conferences and collaborated on several Titan and cometary projects.

    ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1
  • The Variability of Carbon Monoxide Abundances Among Oort Cloud Comets

    Direct observations of neutral CO in multiple wavelength regimes (radio, infrared and ultraviolet) have established a wide range for measured CO abundances (relative to water), ranging from a few tenths of a percent to ~30%. But the largest complexity when interpreting measurements of CO stems from its competing roles as a primary (parent) vs product species. For instance, CO is a principal product of CO2 dissociation, so comets rich in CO2 should also reveal a significant production rate for CO — this product CO is extended and its detection is strongly dependent on the instrumental field-of-view (FOV). Prior to 2013, only six comets within 2.5 AU of the Sun (where both H2O and CO are active primary volatiles) were identified as being enriched in native CO. During late 2013, we confirmed a relatively high abundance of CO in C/2013 R1 (Lovejoy; hereafter C/2013 R1), supporting the existence of a so-far sparse (yet growing) fraction of CO-rich comets.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2 7.1
  • Volatile Composition of Comets: Emphasis on Oxidized Carbon

    DiSanti’s research emphasizes the chemistry of volatile oxidized carbon in comets, in particular the efficiency of converting CO to H2CO and CH3OH through reduction reactions on the surfaces of icy grains prior to their incorporation into the cometary nucleus. Additionally, oxidation reactions on grains can play a significant role, particularly for CO-enriched, C2H2-depleted comets such as C/2009 P1 (Garradd; see item 1 under Section 3 below). Such processes produce precursor molecules that (if delivered to Earth through impact of comet nuclei) could have enabled the emergence of life, and so are highly relevant to Astrobiology.

    ROADMAP OBJECTIVES: 3.1 3.2