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Project Reports

• Project 1: Looking Outward: Studies of the Physical and Chemical Evolution of Planetary Systems

  We continue to apply theory and observations to investigate the nature and distribution of extrasolar planets both through radial velocity and astrometric methods, the composition of circumstellar disks, early mixing and transport in young disks, and late mixing and planetary migration in the Solar System, and Solar System bodies.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1

• Project 1: Interstellar Origins of Preplanetary Matter

  Interstellar space is rich in the raw materials required to build planets and life, including essential chemical elements (H, C, N, O, Mg, Si, Fe, etc.) and compounds (water, organic molecules, planet-building minerals). This research project seeks to characterize the composition and structure of these materials and the chemical pathways by which they form and evolve. The long-term goal is to determine the inventories of proto-planetary disks around young sun-like stars, leading to a clear understanding of the processes that led to our own origins and insight into the probability of life-supporting environments emerging around other stars.

  ROADMAP OBJECTIVES: 1.1 3.1

• 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

• Life Underground

  Our multidisciplinary team from USC, Caltech, JPL, DRI, and RPI 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, 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 seek to carry out in situ life detection and characterization experiments, employ numerous novel and traditional techniques to culture heretofore unknown intraterrestrial archaea and bacteria, and incorporate new and existing data into regional and global metabolic energy models.

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

• Alteration of Asteroid Surfaces, Martian Meteorites and Terrestrial Rocks

  The inner solar system is relatively dry, but recent discoveries of water ice on the Moon, the subsurface of Mars, and potentially on a small class of asteroids known as main belt comets (MBCs), has forced us to re-evaluate our understanding of the inner solar system volatile distribution. Understanding the water content in asteroids and its evolution with time will be critical to constrain the origin and evolution of water in the asteroid belt.

  Interpreting the early aqueous history of the solar system requires an understanding of the processes that alter the original materials, including secondary alteration of minerals within parent bodies, and processes termed space weathering that influence surface layers. The nakhlite group of Martian meteorites is known to contain secondary alteration minerals that formed on Mars. We studied the fine-scale mineralogy and chemistry of these alteration minerals, and compared them to terrestrial alteration minerals formed in the Antarctic. The aim of these comparisons was to determine whether conditions such as water/rock ratio, pH and temperature were similar during the formation of alteration minerals in both planetary environments. Hence, the suitability of the Antarctic as a martian analogue site was tested.

  The distribution of MBCs and asteroids with hydrated minerals provide us with a tool to constrain the position of the snow line within the asteroid belt, which has important implications for the origin and distribution of volatiles for the terrestrial planets. However we need to understand the processes that alter the surface composition to be able to interpret the observations in the context of early solar system volatile distribution. Space weathering has been largely associated with “dry” S-type asteroids and is known to decrease the absorption depths and redden the spectral slopes of their surfaces. Only recently have studies indicated that C-type asteroids experience space weathering as well. Currently there are two contrasting views of how space weathering modifies the surfaces of these asteroids. One study found that the spectral slopes become redder with age, similar to S-type asteroids, but another study found that the spectral slopes become neutral with age. This discrepancy has been attributed to sampling effects and differences in mineralogy among C-type asteroids.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1

• Astrophysical Controls on the Elements of Life, Task 1: High-Precision Isotopic Studies of Meteorites

  The initial Solar System abundances of the short-lived radionuclides (SLRs) ²⁶Al (half life ~0.73 Ma) and ⁶⁰Fe (half life ~2.6 Ma) are important to constrain since, if present in sufficient abundance, these SLRs served as heat sources for dehydration and differentiation processes on planetary bodies. The implications for this work include the astrophysical environment in which the Sun formed, and the abundance of water on the terrestrial planets.

  Research on this task was completed in Year 4.

  ROADMAP OBJECTIVES: 1.1 3.1

• Project 2: Processing of Precometary Ices in the Early Solar System

  The discovery of numerous planetary systems still in the process of formation provides a unique opportunity to see how our own solar system may have formed 4.6 billion years ago. Our research group studies physical processes that determine thermal environments in and around young planetary systems in order to constrain the prebiotic chemistry which can occur there. In one study we have built a unique code which simulates the heating of dense molecular gas in chemically active outflows (CAOs) associated with protostars. Our code will be used to model the wealth of molecular observations of CAOs which will be obtained by SOFIA and other observatories. In another study we have discovered a new mechanism whereby asteroids in the solar nebula are heated by magnetohydrodynamical processes. The goal of the second study is to determine whether asteroids can be warm enough to support prebiotic chemistry in protoplanetary systems that were not innoculated by short-lived radionuclides such as aluminum-26.

  ROADMAP OBJECTIVES: 1.1 3.1 3.2

• Astrophysical Controls on the Elements of Life, Task 2: Model the Chemical and Dynamical Evolution of Massive Stars

  Stars create the chemical elements heavier than hydrogen and helium, with the majority arising from the lives and violent deaths of massive stars in supernova explosions. The starting chemical composition of stars also affects their evolution and that of their associated planets. We have performed computational simulations for a large range of stellar masses to provide predictions for important stellar characteristics (i.e. brightness, temperature, stellar winds, composition) over the stars’ lifetimes and made the data available to the public. We have also simulated the explosions of massive stars to predict the chemical abundances of material ejected from the dying stars and how that material is distributed in the surrounding universe. As a complement, we are modeling how the habitable zones and planets of stars with different abundances evolve.

  ROADMAP OBJECTIVES: 1.1 3.1

• 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

• Task 2.1.1.1: Titan Photochemical Model

  To develop a comprehensive model of the chemistry in Titan’s atmosphere including condensation of molecules onto grains, and sublimation back to the gas.

  ROADMAP OBJECTIVES: 2.2 3.1

• Disks and the Origins of Planetary Systems

  This task is concerned with the evolution of complex habitable environments. The planet formation process begins with fragmentation of large molecular clouds into flattened disks. This disk is in many ways an astrochemical “primeval soup” in which cosmically abundant elements are assembled into increasingly complex hydrocarbons and mixed in the dust and gas within the disk. Gravitational attraction among the myriad small bodies leads to planet formation. If the newly formed planet is a suitable distance from its star to support liquid water at the surface, it is in the so-called “habitable zone.” The formation process and identification of such life-supporting bodies is the goal of this project.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 4.1 4.3

• 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

• Task 2.1.1.2: Titan Photochemistry

  The Caltech effort has focused on the chemistry of hydrocarbons in the atmosphere of Titan and its relation to aerosols. We have an effort for analyzing the stellar occultation data from Cassini/UVIS instrument. The mean optical depth as a function of line of sight impact parameter is derived for the spectral range between 1700 and 1900 Å from stellar occultations.

  ROADMAP OBJECTIVES: 2.2 3.1

• Astrophysical Controls on the Elements of Life, Task 3: Model the Injection of Supernova Material Into Star-Forming Molecular Clouds

  The goal of this task is to see if material ejected from a star that has exploded as a supernova can make its way into the gas as it is forming new solar systems. It has been expected that this material, because it is moving so fast (> 2000 km/s) when it hits the cold, dense molecular cloud in which stars are forming, would shock, heat up, and then “bounce” off of the cloud boundary.

  ROADMAP OBJECTIVES: 1.1 3.1

• Project 3: The Origin, Evolution, and Volatile Inventories of Terrestrial Planets

  We study the origin and evolution of the terrestrial planets with a special emphasis on CHON volatiles, their delivery and retention in the deep interiors of terrestrial planets. We will experimentally investigate how CHON volatiles may be retained even during magma ocean phases of terrestrial evolution. We investigate the early Earth’s recycling processes studying the isotopic composition of diamonds, diamond inclusions, and associated lithologies. We continue to integrate new information from the NASA Messenger Mission to Mercury into the broader context of understanding the inner Solar System planets.

  ROADMAP OBJECTIVES: 1.1 3.1 4.1

• 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 analyzed the amino acid and nucleobase content of a martian meteorite; our findings suggested the presence of extraterrestrial amino acids in that meteorite. We studied irradiated benzene ices to determine that this type of radiation chemistry may have produced some of the complex aromatics found in meteorites. We identified amino acids for the first time in high-metal carbonaceous chondrite classes, supporting the idea of multiple formation mechanisms for these astrobiologically relevant compounds. We supported development of a liquid chromato-graphmass spectrometer aimed at in situ analyses of amino acids and chirality on airless bodies including asteroids and the outer planet’s icy moons Enceladus and Europa. We hosted a graduate student, an undergraduate, and a high-school intern, and 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

• Ice Chemistry: Radiation Induced Chemical Processing

  Prebiotic molecules such as amino acids, sugar, and sugar alcohols are thought to be delivered to the early Earth by meteorites and comets and may have played crucial role in the origin of life. However, there is no conclusive evidence of these molecules found in the interstellar medium. However, simple precursors such as formaldehyde, acetaldehyde, acetone, propanal, propenal, and acetic acid were observed in the interstellar medium such as toward the star forming region SgrB2. Extraterrestrial ices with abundant molecules like water, methane, carbon monoxide, carbon dioxide, ammonia, and methanol are exposed to ionizing radiation such as galactic cosmic radiation and UV radiation. Here, we have been investigating the effect of ionizing radiation on simple astrophysical ice representatives in the solid state using FTIR, UV-VIS, Raman spectroscopy as well as the products analyzed in the gas phase (fragment free reflectron time-of-flight mass spectroscopy combined with single photon ionization (ReTOF-PI)) while subliming to the gas phase after a controlled temperature desorption. Our laboratory simulation experiments provide clear evidence of the formation of large number of aldehydes, ketones such as acetaldehyde, acetone in methane-carbon monoxide ices, formation of simple sugar alcohols (glycerol) in methanol ices and possibly formation of amino acid (glycine) in mixed ices of water, carbon dioxide, methane, and ammonia.

  ROADMAP OBJECTIVES: 3.1 3.2

• Project 4: Geochemical Steps Leading to the Origins of Life

  We investigate the geochemical steps that may have lead to the origin of life, focusing on identifying and characterizing mineral catalyzed organic reaction networks that lead from simple volatiles, e.g., CO₂, NH₃, and H₂, up to greater molecular complexity. We continue to explore the role of minerals to enhance molecular selection, both isomeric and chiral selection, as well as molecular organization on mineral surfaces. We continue to refine our understanding of the evolution of mineralogical complexity in the context of planetary evolution.

  ROADMAP OBJECTIVES: 3.1 3.2

• 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

• 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 4: Survival of Sugars in Ice/Mineral Mixtures on High Velocity Impact

  Understanding the delivery and preservation of organic molecules in meteoritic material is important to understanding the origin of life on Earth. Though we know that organic molecules are abundant in meteorites, comets, and interplanetary dust particles, few studies have examined how impact processes affect their chemistry and survivability under extreme temperatures and pressures. We are investigating how impact events may change the structure of simple sugars, both alone and when combined with ice mixtures. The experiments will allow us to understand how sugar chemistry is affected by high pressure events and to contrast the survival probabilities of sugars in meteorite and comet impacts. This will lead to a better understanding of how organic molecules are affected during their delivery to Earth. This project leverages expertise in two different NAI nodes, increasing collaborative interaction among NAI investigators.

  ROADMAP OBJECTIVES: 1.1 3.1 4.1 4.3

• Astrophysical Controls on the Elements of Life, Task 4: Model the Injection of Supernova Material Into Protoplanetary Disks

  The goal of this project has been to determine whether supernova material could be injected into a proto-planetary disk, the disk of gas and dust from which planets form. A secondary issue is whether these materials would be mixed within the disk efficiently, and whether such an injection into our own proto-planetary disk can explain the isotopic evidence from meteorites that the solar system contained short-lived radionuclides like ²⁶Al.

  ROADMAP OBJECTIVES: 1.1 3.1

• Task 2.1.2.2: Shortwave Solar Flux at Titan’s Surface

  What can we learn about pre-biotic chemistry by studying Titan? The surface of Titan is a special place for the study of pre-biotic chemistry because that is where the organic haze sedimenting from the atmosphere can come in contact with liquid water (briefly, from cryovolcanic eruptions) to form amino acids and other molecules relevant to life. But an energy source is also needed, and this may come from short-wave (ultraviolet – blue) solar radiation that makes its way through Titan’s dense haze layer to the surface. In this study we calculated the amount of UV-blue solar flux at Titan’s surface based on measurements made by the Descent Imager/Spectral Radiometer (DISR) instrument on the Huygens Probe coupled with radiative transfer models that include haze optical properties.

  ROADMAP OBJECTIVES: 2.2 3.1 3.2 3.3

• Astrophysical Controls on the Elements of Life, Task 5: Model the Variability of Elemental Ratios Within Clusters

  We carried out studies of self-enrichment of the earliest star clusters, building on the turbulence simulations in Pan & Scannapieco (2010) and Pan et al. (2011), and developing a method to track the formation of metal free stars.

  ROADMAP OBJECTIVES: 1.1 3.1

• Solar System Volatile Distributions – Icy Bodies

  One of the forefront areas of science related to the early solar system, and highlighted in the Plane-tary Decadal Survey, is the need to understand the source of volatiles for planets in the habitable zone and the role that primitive bodies played in creating habitable worlds. Comets, which have escaped the high-temperature melting and differentiation that asteroids experience, are “astrobio-logical time capsules” that have preserved a valuable record of the complex chemical and physical environment in the early solar Nebula. In the early 1970’s we were at the threshold of a new era of asteroid physical studies. After four decades the asteroid population is yielding information about compositional gradients in the nebula, aqueous alteration processes in the protoplanetary disk and the early dynamic environment as the giant planets formed. Similarly, large surveys of Kuiper belt objects have lead to a new understanding of the dynamic solar system architecture and of the outer solar system composition and collisional environment. Surveys are beginning to yield information on comet physical properties, including spectroscopic measurement of volatile comet outgassing at optical and IR wavelengths, nucleus sizes and activity from space and from the ground. As these surveys obtain small solar system body data, they enable a new science that involves studies of clas-ses, secular evolution of physical characteristics and processes. Our team is undertaking several studies to directly observe the volatiles in small bodies and the mechanisms of their activity, to dis-cover and characterize objects that may represent previously unstudied reservoirs of volatiles and to discover the interrelationships between various classes of small bodies in the context of the new dynamical solar system models.

  ROADMAP OBJECTIVES: 1.1 2.2 3.1

• 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, we are poised to break open the study of young exoplanetesimals, 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 4.3 7.2

• Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements

  Abundances of both common and trace elements can have substantial effects on the habitability of stellar systems. We study the formation and composition of structures in supernova explosions that deliver isotopes that influence habitability to material that will form new stars and planets. We examine ratios of elements that have substantial effects of the mineralogy and interiors of planets. The relative abundances of common elements vary substantially among nearby stars, and we find that the impact of this on a star’s evolution can change the amount of time its planets are habitable by large factors.

  ROADMAP OBJECTIVES: 1.1 3.1

• Task 2.2.1: Characterization of Aerosol Nucleation & Growth on Titan

  The scientific goal of this task is to elucidate the mechanisms and develop a quantitative understanding of particle formation and growth in the Titan atmosphere.

  ROADMAP OBJECTIVES: 3.1

• 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

• Habitable Planet Formation and Orbital Dynamical Effects on Planetary Habitability

  The VPL explores how variations in orbital properties affects the growth, evolution and habitability of planets. The formation process must deliver the appropriate ingredients for life to a planet in order for it to become habitable. After planets form, interactions between a habitable planet at its host star and/or other planets in the system can change planetary properties, possibly rendering the planet uninhabitable. The VPL models these processes through computer models in order to understand how the Earth became and remains habitable, as well as examining and predicting habitability on planets outside the Solar System.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 4.3

• 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 7: 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

• Task 3.1.1: Stimulated Pre-Biotic Reactions on Titan Surfaces

  The program at Georgia Tech. involves Dr. Claire Pirim (postdoctoral researcher) and Dr. Thomas Orlando (PI). It focuses on understanding the reactions occurring on Titan’s surface with an emphasis on determining whether mineral deposits from meteoritic impacts can catalyze the formation of more complex molecules possessing a prebiotic character.

  ROADMAP OBJECTIVES: 3.1 3.2

• Project 8: 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

• Task 3.2: 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 to 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

• Fischer-Tropsch-Type Reactions in the Solar Nebula

  We are studying Fischer-Tropsch-Type reactions in order to investigate the formation of complex hydrocarbons by surface-mediated reactions using simple gases (CO, N₂, and H₂) found in the early Solar Nebula. Although several theories exist as to how hydrocarbons are formed in the early Solar System, 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. This method for generating hydrocarbons is important because it provides insight or potential as to how comets, meteorites, and the early Earth may have obtained their first hydrocarbon inventory. From this study, we have expanded the FTT experiments into several related areas of interest, of which the formation of amino acids and the trapping of noble gases are two examples.

  ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2

• Task 3.3.1: Solubility of Organics in Simulated Titan Lake Solutions

  Widespread lakes of liquid methane and ethane were discovered on Titan by the Cassini mission in 2006, which naturally motivates questions about the solubility of surface materials in the liquid. Our goal is to measure the solubilities of Titan surface and atmospheric species in cryogenic liquid hydrocarbons, in order to constrain the composition of the hydrocarbon lakes, and provide an understanding into the nature of erosion and sedimentation on Titan. To date, we have measured the solubilities of argon and krypton in liquid methane and ethane, and the solubilities of benzene, naphthalene, and biphenyl in liquid ethane. Relatively high organic solubilities suggest that liquid hydrocarbon based weathering and sorting of surface organics should be occurring on Titan.

  ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2

• Fundamental Properties Revealed by Parent Volatiles in Comets

  We detected prebiotic molecules in the atmosphere of the distant comet C/2006 W3 (Christensen), which has spent its entire orbital period well outside the zone of active water sublimation. We also integrated our spectral-spatial measurements of H₂O emission in comet 73P/ Schwassmann-Wachmann 3B with state-of-the-art 3D physical models of the inner cometary atmosphere, leading to new insights on a previously unidentified heating of coma gas from vaporizing icy grain mantles. And, we published a fluorescence model needed to interpret emission from deuterated methane released from cometary nuclei. These projects aim at improved understanding of cometary chemistry – a test bed for the contribution of comets to the delivery of exogenous prebiotic organics and water to early Earth, hypothesized as a precursor event to the emergence of the biosphere.

  ROADMAP OBJECTIVES: 2.2 3.1 4.3

• 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

• 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

• Task 3.3.2: Trapping of Methane and Ethane in Titan Surface Materials

  We demonstrate that solid benzene can trap significant amounts of ethane and methane within its crystal structure at Titan surface temperatures. Experiments also suggest that liquid ethane can diffuse into solid benzene, resulting in the formation of a co-crystalline structure. This implies that lake edges and evaporite basins on Titan may hold important quantities of ethane. These results can help explain the release of methane observed at the Huygens landing site, and point toward a large possible reservoir of methane and ethane hidden within Titan’s surface organics.

  ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2

• Task 3.4.1: Nuclear Magnetic Resonance Spectroscopy Studies of Titan Organic Analogues: Analytical Potential

  Nuclear magnetic resonance spectroscopy (NMR) has tremendous potential for the quantitative identification of solar system organic molecules of simple to complex nature with absolute structural identification. We have investigated its potential for the elucidation of very complex mixtures of Titan aerosol haze analogues (Tholins) with identification of the major components of modest complexity using 1, 2 and 3 dimensional spectral techniques. We have also performed studies of the utility of low resolution NMR on low temperature liquid hydrocarbon mixtures analogous to Titan lake liquids towards the development of multidimensional NMR instrumentation capable of future flight missions to solar system bodies of organic composition.

  ROADMAP OBJECTIVES: 2.2 3.1 3.2

• Long-Term Variation of High Energy Activity of Young Stars in Mass Accretion Outburst and Quiescence

  High-energy photons in the young stellar environment are known to stimulate chemical reactions of molecules and producing prebiotic materials that might later be incorporated in-to comets, and through them into young planets. Observational tests are sorely needed to assess the significance of such processing for Astrobiology, and to guide development of theoretical models for chemical evolution in protoplanetary environments.

  ROADMAP OBJECTIVES: 2.2 3.1

• NNX09AH63A Origin and Evolution of Organics in Planetary Systems

  The Blake group has been carrying out joint observational and laboratory program with NAI node scientists on the water and simple organic chemistry in the protoplanetary disk analogs of the solar nebula and in comets. Observationally, we continue to build on our extensive (>100 disks) Spitzer IRS survey of the infrared molecular emission from the terrestrial planet forming region of disks with follow-up work using the high spectral resolution ground-based observations of such emission (via the Keck and the Very Large Telescopes, the Herschel Space Observatory, and ALMA) along with that from comets. This year, we emphasized the disk systems in which we have probed the outer disk’s water emission with the Herschel HIFI instrument. With Herschel PACS we have measured the ground state emission from HD for the first time, yielding much more accurate mass estimates, that we have used in turn to carry out the first detailed examination of the radial water abundance structure in the planet-forming environments represented by the so-called transitional disk class. In the laboratory, we have developed a novel approach to broad-band chirped pulse microwave spectroscopy that promises to drop the size, mass and cost of such instruments by one to two orders of magnitude. We are using the new instrument to measure the rotational spectra of prebiotic compounds, and our existing THz Time Domain Spectrometer to characterize their large amplitude vibrations. Looking forward, these techniques have the potential to make site-specific stable isotope measurements, a capability we will explore with GSFC Node scientists.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1

• 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

• 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

• SMACK: A New Algorithm for Modeling Collisions and Dynamics of Planetesimals in Debris Disks

  Finding habitable planets and understanding the delivery of volatiles to their surfaces requires understanding the disks of rocky and icy debris that these planets orbit within. But modeling the physics of these disks is complicated because of the challenge of tracking collisions among trillions of trillions of colliding bodies. We developed a new technique and a new code for modeling the collisions and dynamics of debris disks, called “SMACK” which will help us interpret images of planetary systems to better understand how planetesimals transport material within young planetary systems.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1

• The Evolution of Organics in Space

  The molecular heritage of our Solar System stretches back to the interstellar cloud from which it formed. Knowledge of the chemistry of this cloud is crucial to understanding the process of star and planet formation; this is part of the field of astrochemistry. Since much of astrochemistry deals with the organic molecules found in space and in solar system environments, astrochemistry itself may be considered part of the larger field of astrobiology. The present project includes both observations of these organic molecules and participating in the preparation of an Encyclopedia of Astrobiology.

  ROADMAP OBJECTIVES: 3.1

• 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

• 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 2 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

• 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