The branch conducts interdisciplinary basic research in exobiology to understand pre-biotic chemistry, and the origin, evolution, distribution, and future of life in the Universe. We provide an interface between the external academic community and NASA programs. Our work also informs the selection, design and development of NASA life detection missions; the design and fabrication of spaceflight instruments to evaluate habitability and detect biosignatures; and the interpretation of astrobiology mission and astronomical data.
The CheMin Instrument
The Exobiology Branch is home to David Blake, the Principal Investigator for the CheMin instrument on the Mars Science Laboratory, scheduled for launch in 2011.
The CheMin instrument utilizes X-ray diffraction and flourescence to provide difinitive minerology of rock samples (both elemental analysis and crystal structure determination).
Early Habitable Environments and the Evolution of Complexity
The Exobiology Branch is home to David Des Marais, the Principal Investigator of the NASA Astrobiology Institute (NAI) Ames Team, which focuses on Early Habitable Environments and the Evolution of Complexity. The overarching goal of this scientific program is to understand the creation and distribution of early habitable environments in emerging planetary systems. The Ames Team provides a program of integrative, mission-enabled and mission-enabling research on habitability and a thematically related program of education and public outreach focused around informal education in high-impact venues. Andrew Pohorille, Tori Hoehler, and Sandy Dueck are also members of the Exobiology Branch and hold key roles as Lead Co-Investigators on the team. To learn more about the NAI Ames Team, visit their website at www.amesteam.arc.nasa.gov.
Origin of Life Research
For nearly 40 years, the Exobiology Branch at Ames has been the main center for origins of life research at NASA, and a world leader in this scientific area. Currently, the branch has the unique feature of being the only center within the NASA Astrobiology Program that has a sustained, long-term program of theoretical and computational studies on the origins of life. This research program, which contains both molecular and system-level components, is leveraged by the supercomputing facilities at Ames and by Ames’ status as the NASA lead center in information science and technology.
The image shown above is the cover art for the latest issue of the Journal of Physical Chemistry, highlighting an article by Andrew Pohorille, a Principal Investigator in the Branch, with co-authors Christopher Jarzynski and Christophe Chipot, titled “Good practices in free-energy calculations”. From the abstract: “As access to computational resources continues to increase, free-energy calculations have emerged as a powerful tool that can play a predictive role in a wide range of research areas. … In this contribution, the current best practices for carrying out free-energy calculations using free energy perturbation and nonequilibrium work methods are discussed demonstrating that, at little to no additional cost, free-energy estimates could be markedly improved and bounded by meaningful error estimates.”
Dr. Pohorille is also the recepient of this year’s H. Julian Allen Award, bestowed by NASA Ames for best research paper. Titled “Calculating free energies using average force”, the paper appeared in the Journal of Chemical Physics (co-author Eric Darve), Volume 115, Number 20, November 2001. According to the Citation Index in the Web of Science the paper has been cited 111 times as of March 2010. From the abstract: “A new, general formula that connects the derivatives of the free energy along the selected, generalized coordinates of the system with the instantaneous force acting on these coordinates is derived. The instantaneous force is defined as the force acting on the coordinate of interest so that when it is subtracted from the equations of motion the acceleration along this coordinate is zero. The formula applies to simulations in which the selected coordinates are either unconstrained or constrained to fixed values.”
The Branch is also home to Dr. Arthur Weber, a SETI Institute researcher, who works together with his wife Esther to study the pre-biotic chemistry of sugars, and how these molecules may have led to the origin of life.
The Branch is housed in Building 239 at NASA Ames Research Center. Laboratory facilities available include analytical equipment for the characterization of gas and aqueous chemistry, instruments for the detection of various biomarkers including sugars and organics, microbiology facilities including the culture of microbial mat communities, electron and RAMAN microscopes, a molecular biology suite, and informatics computational capabilities.
Code SSX Highlights
Tori Hoehler (SSX) delivered a keynote lecture at the 2011 meeting of the International Society for Subsurface Microbiology. Hoehler’s lecture, entitled, “Energetic constraints on subsurface life: A case study of methanogenesis in serpentinizing systems” focused on constraining the habitability of subsurface environments through thermodynamic and bioenergetic models. The lecture focused on a case study developed […]
Short story: We have taken repeat images of dark flows at several sites on Mars using the Mars Reconnaissance Orbiter’s (MRO) High Resolution Imaging Science Experiment (HiRISE) camera. These features extend down slope from bedrock outcrops and appear to lengthen during warm seasons and fade in cold seasons. Flows recur over periods of months (to […]
The research concerns the mechanism leading to rapid global warming, about 600 million years ago, that ended the so-called ‘Snowball Earth’ glacial period. Methane, a strong greenhouse gas, has been implicated as a playing a key role in this instance of rapid climate change. A key piece of evidence supporting this idea are carbonate rocks, […]
Ames’ Leslie Bebout is featured in an article about growing algae on long term space flights in the Algae Industry Magazine: http://www.algaeindustrymagazine.com/aim-interview-nasa-ames-dr-leslie-prufert-bebout/ May 22, 2011, by David SchwartzAlgaeIndustryMagazine.com […]
Ames Scientists David Blake (Exobiology), Tori Hoehler (Exobiology) and Chris McKay (Planetary Systems) will be featured in an upcoming Quest episode on KQED. The episode, which has a segment called “Searching for life on Mars with NASA Ames’ rover” will air on May 4th at 7:30 PM on KQED. The segment highlights Ames involvement in […]
Tori Hoehler presented two invited lectures during the past two weeks. The first, entitled, “Equating energy and biological potential” was presented at a symposium on deep biosphere sediment microbiology. The symposium was organized by the Dark Energy Biosphere Institute. The second talk, entitled, “Physicochemical characteristics and biological potential of aqueous environments beyond Earth” was presented […]
Tori Hoehler (SSX) presented the Caltech Astronomy & Astrophysics Colloquium on February 2. The lecture, entitled, “Physical and chemical toeholds for exoplanet bioastronomy” was designed to demonstrate conceptually and by example that significant functional constraints can be emplaced on the core astrobiological concepts of habitability and biosignatures solely by reference to fundamental principles in chemistry […]
Tori Hoehler presented a keynote address at the international Extremophiles 2010 conference in Ponta Delgada, Azores. The lecture was entitled, “Compound extremes and energy limitation in aqueous environments on Mars: A case-study of methanogenesis in serpentinizing systems“. The Extremophiles conference is an annual meeting highlighting new research into microorganisms that inhabit environments characterized by physicochemical […]
An Exploration Systems Mission Directorate to support crew health and performance in space exploration proposal was successfully selected as a step 1 proposal under the leadership of Orlando Santos and Fathi Karouia from the Exobiology Branch to assess what changes are occurring within the astronaut’s microbial communities during long duration spaceflight that may induce health […]
Seeking Signs of Life: A Symposium Celebrating the 50th Anniversary of NASA’s Exo/Astrobiology Program aired on Thursday October 14, 2010. http://www.livestream.com/astrobiology50th […]