NASA ASTROBIOLOGY STRATEGY 2015 i CONTRIBUTIONS Editor-in-Chief Lindsay Hays, Jet Propulsion Laboratory, California Institute of Technology Lead Authors Laurie Achenbach, Southern Illinois University Karen Lloyd, University of Tennessee Jake Bailey, University of Minnesota Tim Lyons, University of California, Riverside Rory Barnes, University of Washington Vikki Meadows, University of Washington John Baross, University of Washington Lucas Mix, Harvard University Connie Bertka, Smithsonian Institution Steve Mojzsis, University of Colorado Boulder Penny Boston, New Mexico Institute of Mining and Uli Muller, University of California, San Diego Technology Matt Pasek, University of South Florida Eric Boyd, Montana State University Matthew Powell, Juniata College Morgan Cable, Jet Propulsion Laboratory, California Institute of Technology Tyler Robinson, Ames Research Center Irene Chen, University of California, Santa Barbara Frank Rosenzweig, University of Montana Fred Ciesla, University of Chicago Britney Schmidt, Georgia Institute of Technology Dave Des Marais, Ames Research Center Burckhard Seelig, University of Minnesota Shawn Domagal-Goldman, Goddard Space Flight Center Greg Springsteen, Furman University Jamie Elsila Cook, Goddard Space Flight Center Steve Vance, Jet Propulsion Laboratory, California Institute of Technology Aaron Goldman, Oberlin College Paula Welander, Stanford University Nick Hud, Georgia Institute of Technology Loren Williams, Georgia Institute of Technology Pauli Laine, University of Jyväskylä Robin Wordsworth, Harvard University Release Date: October 2015 CONTRIBUTIONS | ii NASA ASTROBIOLOGY STRATEGY 2015 Authors Abigail Allwood Greg Fournier Emily Knowles Kevin Redding Jan Amend Reza Ghadiri David Krakauer Chris Reinhard Ariel Anbar Damhnait Gleeson Pauli Laine Sarah Rugheimer Linda Billings David Grinspoon James Lyons Frank Schmidt Robert Blankenship Michael Hecht Timothy Lyons Everett Shock Alan Boss Eric Herbst Francis McCubbin Steinn Sigurdsson Rogier Braakman Christopher House John McCutcheon Kelsi Singer Colleen Cavanaugh Nick Hud Leslie Mullen Alexander Smirnov Shelley Copley David Jablonski Michael Mumma Eric Smith Peter Driscoll David Jacobs Wayne Nicholson Paul Sniegowski Andy Ellington Clark Johnson Ron Oremland Sanjoy Som Doug Erwin David Johnston Mark Patzkowsky Michael Tice Paul Falkowski Nancy Kiang Andrew Pohorille Wim Vermaas Jamie Foster Rob Knight Lisa Pratt Doug Whittet Reviewers Steven Benner Vikki Meadows Steve Freeland Harold Morowitz Kate Freeman Dianne Newman Nigel Goldenfeld Dan Rothman Jerry Joyce John Rummel Andy Knoll | CONTRIBUTIONS NASA ASTROBIOLOGY STRATEGY 2015 iii Contributors Daniel Apai Lindy Elkins-Tanton Vikki Meadows Martin Schoonen Laurie Barge Francois Forget Karen Meech Matt Schrenk Steve Benner Danny Glavin D'Arcy Meyer-Dombard Barbara Sherwood-Lollar Rohit Bhartia Nigel Goldenfeld Ian Miller Kelsi Singer Jade Bond Yuri Gorby Dianne Newman Jennifer Solis Rogier Braakman Murthy Gudipati Alison Olcott Marshall Sanjoy Som Alex Bradley Ken Halanych Shuhei Ono Ramunas Stepanauskas Martin Brasier Trinity Hamilton Beth Orcutt Roger Summons Will Brinckerhoff Tori Hoehler Victoria Orphan Dawn Sumner Roger Buick Julie Huber Raymond Petry Jack Szostak Aaron Burton Jerry Joyce Ray Pierrehumbert Marika Tarasashvili Michael Callahan Christine Keating Amisha Poret-Peterson Sara Walker Dawn Cardace Andy Knoll Susannah Porter Rachel Whitaker Henderson Cleaves Ram Krishnamurthy Louise Prockter Susanna Widicus Weaver George Cody Lee Kump Ramses Ramirez Kevin Zahnle Frank Corsetti Niles Lehman Sean Raymond Nicolle Zellner Alysia Cox Karen Lloyd Minik Rosing Aubrey Zerkle Steve D’hondt Michael Madigan Olivier Rouxel Olga Zhaxybayeva Peter Doran Tom McCollom Sarah Rugheimer Timothy Zwier Bethany Ehlmann Image Providers David Flannery Jenny Mottar Jamie Foster Pam Reid Jonathan Franks John Stolz Special Acknowledgements Thanks to Andy Burnett, David Loman, Costa Michailidis, Stavros Michailidis, and Tim Morley of KnowInnovation for facilitation of two in-person workshops, many virtual discussions, and online curation of the assembled material. Additional thanks to the JPL documentation/graphics team: Amanda Aguayo, Joon Park, Samantha Ozyildirim, Ed Sewall, and Mary Young; and Raytheon Web Solutions team: Harman Smith and Randii Oliver. Special thanks to Jenny Mottar for creation of the cover art. CONTRIBUTIONS | iv NASA ASTROBIOLOGY STRATEGY 2015 CONTENTS CONTRIBUTIONS .............................................................................................................................................................. i CONTENTS ...................................................................................................................................................................... iv EXECUTIVE SUMMARY ................................................................................................................................................ viii Identifying Abiotic Sources of Organic Compounds ............................................................................................... ix Synthesis and Function of Macromolecules in the Origin of Life ............................................................................ ix Early Life and Increasing Complexity ...................................................................................................................... x Co-Evolution of Life and the Physical Environment ................................................................................................. x Identifying, Exploring, and Characterizing Environments for Habitability and Biosignatures ................................. xi Constructing Habitable Worlds ............................................................................................................................... xi Conclusion ............................................................................................................................................................. xii INTRODUCTION ............................................................................................................................................................ xiii UPDATES TO THE ROADMAP ....................................................................................................................................... xx 1 IDENTIFYING ABIOTIC SOURCES OF ORGANIC COMPOUNDS ...................................................................... 1 Introduction ............................................................................................................................................................. 1 Why is This Topic Important? .................................................................................................................... 2 What Does This Research Entail? ............................................................................................................ 3 Progress in the Last Ten Years ................................................................................................................. 6 Areas of Research Within Abiotic Sources of Organic Compounds .......................................................... 8 I. What Were the Sources, Activities, and Fates of Organic Compounds on the Prebiotic Earth? .............................................................................................................................. 8 II. What is the Role of the Environment in the Production of Organic Molecules? ........................... 11 III. What is the Role of the Environment on the Stability and Accumulation of Organic Molecules? ...................................................................................................................... 14 IV. What Constraints Can the Rock Record Place on the Environments and Abiotic Reactions of the Early Earth? ........................................................................................... 16 Challenges for the Next Ten Years ......................................................................................................... 17 Further Reading.................................................................................................................................................... 19 2 SYNTHESIS AND FUNCTION OF MACROMOLECULES IN THE ORIGIN OF LIFE ......................................... 20 Introduction ........................................................................................................................................................... 20 Why is This Topic Important? .................................................................................................................. 21 What Does This Research Entail? .......................................................................................................... 22 Progress in the Last Ten Years ............................................................................................................... 27 Areas of Research within Synthesis and Function of Macromolecules in the Origin of Life .................... 28 I. Paths to Today’s DNA/RNA/Protein-Dominated World ................................................................ 28 Challenges for the Next Ten Years ......................................................................................................... 32 Further Reading.................................................................................................................................................... 33 | CONTENTS NASA