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Project Reports

• 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

• 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

• 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

• 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

• 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

• Advancing Methods for the Analyses of Organic Molecules in Sediments

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

  ROADMAP OBJECTIVES: 2.1 2.2 7.1

• 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

• Exploring the Chemical Composition of Hot Exoplanets With the Hubble Space Telescope

  We have used the new Wide Field Camera 3 (WFC3) instrument on the Hubble Space Telescope (HST) to observe exoplanet transit and eclipse measurements for a number of highly irradiated, Jupiter-mass planets, with a focus on confirming which planets exhibit water absorption in transit and/or eclipse and measuring the characteristic brightness temperature at these wavelengths. Measurements of molecular absorption in the atmospheres of these planets offer the chance to explore several outstanding questions regarding the atmospheric structure and composition of hot Jupiters, including the possibility of bulk compositional variations between planets and the presence or absence of a stratospheric temperature inversion.

  ROADMAP OBJECTIVES: 1.1 1.2 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

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

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

  ROADMAP OBJECTIVES: 2.1 2.2 3.2 7.1

• 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

• 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

• 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

• Fingerprinting Late Additions to the Earth and Moon via the Study of Highly Siderophile Elements in Lunar Impact Melt Rocks

  We have completed analysis of highly siderophile element (HSE) abundances and Os isotopes in seven Apollo 17 impact melt breccias. The project represents a portion of UMd Ph.D. student Miriam Sharp’s dissertation, and the results of three years of GCA summer internships of Lorne Loudin and Iva Gerasimenko. The resulting large database for impact melt rocks from this site is consistent with a dominant signature imparted to rocks from this site by a single major impactor, most likely the impactor that created the Serenitatis basin. The composition of this impactor was broadly chondritic with respect to HSE, but characteristically enriched in Re, Ru and Pd relative to most chondrites that have been analyzed for these elements. The characteristics of the dominant impactor are most similar to chondritic meteorites that are relatively poor in organics and volatiles. These results suggest that the Serenitatis impactor originated in the inner portion of the present asteroid belt. The formation of this basin was likely not a process that delivered substantial water and/or organics to the lunar crust.

  ROADMAP OBJECTIVES: 1.1

• The Astrobiology Walk

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

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