2015 Annual Science Report
NASA Goddard Space Flight Center Reporting | JAN 2015 – DEC 2015
The Goddard Team addresses this central question: Did delivery of exogenous organics and water enable the emergence and evolution of life? In short: Why is Earth wet and alive? Along with the origin of Earth’s water, we seek to better understand which organic compounds are generated in the interstellar and proto-planetary environments and later delivered to planets. We address this goal through observational, theoretical, and laboratory work.
Our investigations embody an integrated program of (a) pan-spectral astronomical observations of comets, circumstellar disks, and exoplanet environments, (b) models of dynamical transport in the early Solar System, (c) laboratory studies of extraterrestrial samples, and (d) realistic laboratory and numerical simulations of inaccessible cosmic environments. Synergistic integration of these areas is essential for testing whether delivery of the building blocks of life – exogenous water and prebiotic organics – enabled the emergence and development of the biosphere. In this ... Continue reading.
GCA astronomer Marc Kuchner studies the dynamics of debris disks, extrasolar analogs to the Kuiper Belt and the asteroid belt in our solar system, using NASA’s supercomputers. He develops numerical models of the orbits and the interactions of the planetesimals in these disks for use in interpreting images of them made with the Hubble Telescope and other NASA observatories. Together, the images and models teach us about how planetary systems form and evolve – the context within which processes affecting our Solar System are evaluated and extended to exo-planetary systems. An important goal is to extend these studies to a wider range of proto-planetary systems, thereby expanding the range of diversity within which the Solar System must be interpreted. Kuchner’s second initiative targets that objective.
Accordingly, Kuchner invited the public to help him discover new planetary systems through a new website, launched in 2014. At DiskDetective.org, volunteers view data from NASA’s Wide-field Infrared Survey Explorer (WISE) mission and three other surveys. WISE measured more than 745 million objects, representing the most comprehensive survey of the sky at mid-infrared wavelengths ever taken. Among these objects, thousands of planetary systems await discovery – recognizable by the dusty disks that surround them. But galaxies, interstellar dust clouds and asteroids also glow in the infrared, which stymies automated efforts to identify these disks. At Disk Detective.org, the volunteers find the disks by watching 10-second videos of objects seen by WISE, then classifying them by clicking on a selection of buttons on their screens.ROADMAP OBJECTIVES: 1.1 1.2
Hydrogen, carbon monoxide and nitrogen gases are abundant in the primitive solar nebula, as are silicate dust and metallic grains. These gases can react on such grain surfaces to produce an abundance of carbon-bearing products that include volatile hydrocarbons, amines, alcohols, aldehydes and acids as well as more complex, less volatile species such as carbon nanotubes. Refractory carbonaceous deposits catalyze additional surface reactions. Nebular environments span a large range in time, temperature, pressure, catalyst composition and secondary reactions. We are working to understand the rates and products of such reactions that could occur in nebular environments.ROADMAP OBJECTIVES: 1.1 3.1
Research by the Blake group (CalTech) supported by the NAI has centered on a joint laboratory and observational program, designed with the participation of Goddard node scientists, that aims to investigate the chemistry of water and simple organics in the protoplanetary disk analogs of the early solar nebula, in comets, and in the atmospheres of extrasolar planets. The laboratory work has involved the creation of novel high bandwidth instruments from the microwave to the THz regime that can probe both gaseous and condensed phase (liquid and solid) materials. Particular emphasis has been placed on the study of small chiral (that is, ‘handed’) organic species, with a view toward establishing whether the homochirality exhibited on the Earth is stochastically or deterministically derived. We combine the laboratory studies with astronomical observations at radio (VLA, GBT, ALMA), far-infrared (SOFIA, Herschel archival data), and infrared (Keck/VLT, Spitzer archival data) wavelengths. A recent highlight is the first detection of a chiral species toward the Galactic Center, as is described in this reportROADMAP OBJECTIVES: 1.1 1.2 3.1
Laboratory Investigations Into Chemical Evolution in Icy Solids: Mars, Carbonaceous Meteorites, and ISM
The goal of this project is to investigate chemical and physical changes and properties of molecules in low-temperature environments, such as found in interstellar space and the outer regions of the Solar System. Some of the molecules studied have been detected in meteorites and samples returned from NASA missions.ROADMAP OBJECTIVES: 2.1 2.2 3.1
We continue to undertake theoretical and observational studies pertaining to the origin and evolution of organics in Planetary Systems, including the Solar System. In this performance period, we have focused on studies aimed at understanding the origin and processing of organics in the earliest evolutionary phases of stars like the Sun. These include formation pathways and related isotopic fractionation effects.
We have continued observational programs designed to explore the chemical composition of comets and establishing their potential for delivering prebiotic organic materials and water to the young Earth and other planets. State-of-the-art international facilities are being employed to conduct multi-wavelength simultaneous studies of comets in order to gain more accurate abundances, distributions, temperatures, and other physical parameters of various cometary species. We are also leading an international collaboration to study the organic composition of Titan with the Atacama Large Millimeter Array (ALMA).ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 7.1 7.2
Analytical Protocols and Techniques for Detection and Quantitative Analysis of Complex Organics in Planetary Environments
Robotic planetary missions enable critical in situ investigations into the character, diversity and distribution of organic compounds in their native environments. The next-generation mass spectrometers being developed for planetary exploration promise enhanced capabilities to elucidate the molecular structure of detected organic compounds via tandem mass spectrometry (MS/MS), and to disambiguate potential biosignatures via ultra high-resolution mass discrimination. The in situ detection and potential sequencing of individual organic polymers using synthetic trans-membrane nanopores is another example of an innovative technology geared towards the identification of key organic compounds. We are engaged in evaluating and extending such innovative technologies to address astrobiological initiatives on future NASA missions.ROADMAP OBJECTIVES: 2.1 2.2 7.1
2015 saw the twelfth session of our summer program for talented science students (Under-graduate Research Associates in Astrobiology), a ten-week residential research program tenured at Goddard Space Flight Center and the University of Maryland, College Park (http://astrobiology.gsfc.nasa.gov/education.html). Competition was again very keen, with an over-subscription ratio of 4.7. Students applied from over 19 Colleges and Universities in the United States, and 4 Interns from 4 institutions were selected. Each Intern carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse laboratories and gaining a broader view of astrobiology as a whole. At summer’s end, each Associate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 6.2 7.1
Serial Measurements of the Volatile Composition of Comet D/2012 S1 (ISON) between 1.2 and 0.34 AU from the Sun
The composition of ices and rocky material in cometary nuclei is central to understanding their origins, and to assessing their possible roles in delivering water and prebiotic organic compounds to the young Earth. For most comets, measurements of primary volatiles (ices contained in the cometary nucleus) exist for only a single date or for very few dates, questioning whether such ‘momentary’ measurements represent the bulk content of the nucleus. The early discovery of the dynamically new, sun-grazing comet C/2012 S1 (ISON) was extremely rare in that it permitted measurements of the abundances of sublimed ices over a large range of heliocentric distance (Rh). As part of a world-wide observing campaign, world-class astronomical observatories provided large amounts of observing time dedicated to studying Comet ISON. Using high-resolution infrared spectroscopy at Keck-2 and the NASA-IRTF, the GCA Team measured production rates for H2O and eight trace gases (CO, C2H6, CH4, CH3OH, NH3, H2CO, HCN, C2H2) on ten pre-perihelion dates that spanned heliocentric distances ranging from 1.21 to 0.34 AU. This project addressed the evolution in molecular production and composition as the comet approached the Sun. GCA members also investigated the spatial distribution of H2O in the near-nucleus coma to identify modes of water release and of heat injection by release from icy grains, and they conducted a sensitive search for HDO to test the potential delivery of Earth’s oceans by such comets.ROADMAP OBJECTIVES: 3.1 3.2
This project addresses a major frontier of planetary science and astrobiology, namely the identification and characterization of habitable (and inhabited) exoplanets. 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. Targeted questions include the possibility of bulk compositional variations among planets, and the presence or absence of a stratospheric temperature inversion on individual planets. In this reporting period, we emphasized four areas:
1. We improved our modeling and analysis of exoplanet transit and eclipse measurements obtained with the Hubble Space Telescope (HST) and the Spitzer Space Telescope on highly irradiated, Jupiter-mass planets.
2. We improved our data analysis methods to better understand aspects of measuring the chemical composition of the planet’s atmosphere, and we advanced the chemical and thermal modeling of the planet’s hot dayside.
3. We developed simulations of future observations with the James Webb Space Telescope (JWST), and we provided science leadership for a future balloon-borne telescope that can perform transit spectroscopy of hot exoplanet atmospheres.
4. We estimated the discovery yield of future Earth-like exoplanet imaging missions as part of the planning process for the next Astrophysics Decadal Survey, and we are now expanding this effort to estimate the science yield from spectroscopic characterization of them.ROADMAP OBJECTIVES: 1.1 1.2 7.2
This project investigates the evolution and stability of water and organic reservoirs in our Solar System, with particular emphasis on the characterization of the current and ancient habitability of planet Mars. We employ extremely powerful observatories (e.g., ALMA, Keck, VLT, future JWST) to acquire high spatial and spectral resolution maps of the isotopic and organic signatures on several bodies in the Solar System. These maps allow us to investigate the stability and evolution of their atmospheres, while localized plumes can be used to identify regions of active release. In this reporting period, we emphasized three areas:
1. We advanced our pioneering work on characterizing the evolution of water on Mars, by developing a new observational plan that combines the power of ALMA, of Keck and of MAVEN to obtain maps of the water D/H signatures on Mars.
2. We identified previously unknown chemical processes affecting singlet-O2 and odd-oxygen on Mars, which may be indicative of a much more active photochemical cycle (with the possible intervention of heterogeneous processes).
3. We provided science leadership in the investigation of Mars with the James Webb Space Telescope (JWST), and established a variety of observing modes and scientific opportunities.ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1
The evolution of protoplanetary disks tells the story of the birth of planets and the formation of habitable environments. Microscopic interstellar materials are built up into larger and larger bodies, eventually forming planetesimals that are the building blocks of terrestrial planets and their atmospheres. With the advent of ALMA and continuing use of the Hubble Space Telescope, we are poised to break open the study of young exo-planetesimals, probing their organic content with detailed observations comparable to those obtained for Solar System bodies. Furthermore, studies of planetesimal debris around nearby mature stars are paving the way for future NASA missions to directly observe potentially habitable exoplanets.ROADMAP OBJECTIVES: 1.1 1.2 3.1 7.2
The Astrobiology Analytical Laboratory (AAL) of the GCA is dedicated to the study of organic compounds derived from past and future sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development. This year, we continued our work analyzing the organic content of carbonaceous chondrites, including analyses of amino acids, aliphatic amines, aldehydes and ketones. We investigated model systems for potentially relevant prebiotic chemistry. We supported the Biomolecule Sequencer project for evaluating DNA-analysis in microgravity environments by flying a MinIon device on the International Space Station. We continued to support development of protocols for a liquid chromatograph-mass spectrometer aimed at in situ analyses of amino acids and chirality on airless bodies, including asteroids and outer-planet icy moons (e.g., Enceladus and Europa). We participated in numerous public outreach and education events. We continued our participation in the OSIRIS-REx asteroid sample return mission and provided support for the Sample Analysis at Mars instrument of NASA’s Mars rover Curiosity.ROADMAP OBJECTIVES: 2.1 3.1
Massachusetts Institute of Technology
NASA Ames Research Center
NASA Goddard Space Flight Center
NASA Jet Propulsion Laboratory
University of California, Riverside
University of Colorado, Boulder
University of Illinois at Urbana-Champaign
University of Montana, Missoula
University of Southern California
University of Wisconsin
VPL at University of Washington