Dragonfly: New Frontiers mission concept study in situ exploration of Titan's prebiotic organic chemistry and habitability E.P. Turtle, J.W. Barnes, M.G. Trainer, R.D. Lorenz, K.E. Hibbard, D.S. Adams, P. Bedini, J.W. Langelaan, K. Zacny, and the Dragonfly Team OPAG, 22 February 2018 TITANExploring Titan, an EarthlikeEXPLORER Organic-Rich World ... Titan System Science – The rich interactions at Titan among the surrounding space environment, the atmosphere, the surface, and the interior mirror processes on Earth. Titan is a dynamic world: clouds and rainfall change on hourly time- scales. On ~16-day timescales, tides rise and fall in lakes of liquid hydrocarbons, drive winds in the atmosphere, and raise stresses deep in the interior. Year-to-year, seasonal changes are observed in atmospheric composition, aerosols, tempera- tures, and wind patterns. On geological timescales, atmospheric evolution occurs via escape, photochemical reactions, and cryovolcanism. Many analogs to Earth have been found. Titan’s surface has been eroded by rivers, the precipitation may be torrential enough to cause fl ash fl oods, and the atmosphere exhibits a greenhouse effect and stratospheric anomalies analogous to Earth’s ozone hole. Titan and the Origins of Life – The inventory of complex organic material on Titan is remarkably rich. Synthesis of or- ganics begins in the active ionosphere; it results in the thick haze lower in Titan’s atmosphere, the surface accumulations of organic liquids and particles that form lakes in polar regions, and the vast expanses of dunes near the equator. Further processing by exposure for thousands of years to liquid water at sites of impacts and cryovolcanism should yield building blocks of life, such as pyrimidines and amino acids. Given such timescales and conditions, Titan holds possibilities for fundamentally new organic chemistry that cannot be reproduced in the laboratory on Earth. Synergistic Science – Owing to its unique atmosphere, Titan engages a more extensive range of scientifi c disciplines than other icy satellites. It is an outstandingNext target for step comparative in planetology, seeking both with answers other satellites and to with the terres- trial planets. Titan’s environment also enables uniquely affordable deployment of a wide array of instrumentation at the surface, in the atmosphere, and in orbit. Thus, fundamentalthe powerful complement of scientifiquestions c tools necessary to understand such a complex system can actually be brought to bear. For example, in situ investigations such as seismic sensors and detailed chemical analyses supportWhat and makes inform an orbital a planet survey of this or diverse moon target. Combinationshabitable? of techniques provide more robustWhat constraints chemical on mysteries such processes as Titan’s interior structureled to and the atmospheric development circulation. of life? § Titan is an ideal destination to answer 1,000 Solar UV 0.0 these questions because it has the key Energetic N2 ingredients known to be necessary for life: 500 Diffusion Particles 0.01 4 CH 4 and Dust CH Energy: Sunlight, photochemistry Particles ar b m Organic material: Abundant carbon and , k e , r e 0.03 complex organics 60 Condensate Haze essu r ltitud P Solvents: Liquid water, as well as methane A 0.1 C H Ice Ø Potential for organics to interact with liquid water at 40 2 6 CH -N Clouds the surFace, e.g., cryovolcanism, impact craters 4 2 0.3 20 Ø Potential for exchange of surface organics with vast Rain Impacts Ethane-methane CH4 H O/NH Melt 1.0 interior ocean seas/lakes Venting 2 3 Organic Dunes 0 seas/lakes 1.5 NH /H O Cryovolcanism? Ø Earth-like world with an active methane cycle River Channels Organic Sediments 3 2 instead of Earth’s water cycle 07-01121-03 Titan’s atmosphere: 07-01121 • Liquid methane could support development of alternate biological systems Ø Surface pressure = 1.5 bar § Titan is an ocean world laboratory to Ø Surface temperature = 94 K investigate primitive chemistry and to Ø Troposphere ~94% N2, ~6% CH4, 0.1% H2 search for biosignatures Ø Complex photochemistry in upper atmosphere à H & N compounds Space Exploration OPAG Meeting, Hampton, VA, 22 February 2018 Next step in seeking answers to fundamental questions What makes a planet or moon habitable? What chemical processes led to the development of life? § Titan is an ideal destination to answer these questions because it has the key ingredients known to be necessary for life: Energy: Sunlight, photochemistry Organic material: Abundant carbon and complex organics Solvents: Liquid water, as well as methane Ø Potential for organics to interact with liquid water at the surFace, e.g., cryovolcanism, impact craters Ø Potential for exchange of surface organics with vast interior ocean Ø Earth-like world with an active methane cycle instead of Earth’s water cycle • Liquid methane could support development of alternate biological systems § Titan is an ocean world laboratory to investigate primitive chemistry and to search for biosignatures Space Exploration OPAG Meeting, Hampton, VA, 22 February 2018 TITANExploring Titan, an EarthlikeEXPLORER Organic-Rich World ... Titan System Science – The rich interactions at Titan among the surrounding space environment, the atmosphere, the surface, and the interior mirror processes on Earth. Titan is a dynamic world: clouds and rainfall change on hourly time- scales. On ~16-day timescales, tides rise and fall in lakes of liquid hydrocarbons, drive winds in the atmosphere, and raise stresses deep in the interior. Year-to-year, seasonal changes are observed in atmospheric composition, aerosols, tempera- tures, and wind patterns. On geological timescales, atmospheric evolution occurs via escape, photochemical reactions, and cryovolcanism. Many analogs to Earth have been found. Titan’s surface has been eroded by rivers, the precipitation may be torrential enough to cause fl ash fl oods, and the atmosphere exhibits a greenhouse effect and stratospheric anomalies analogous to Earth’s ozone hole. Titan and the Origins of Life – The inventory of complex organic material on Titan is remarkably rich. Synthesis of or- ganics begins in the active ionosphere; it results in the thick haze lower in Titan’s atmosphere, the surface accumulations of organic liquids and particles that form lakes in polar regions, and the vast expanses of dunes near the equator. Further processing by exposure for thousands of years to liquid water at sites of impacts and cryovolcanism should yield building blocks of life, such as pyrimidines and amino acids. Given such timescales and conditions, Titan holds possibilities for fundamentally new organic chemistry that cannot be reproduced in the laboratory on Earth. Synergistic Science – Owing to its unique atmosphere, Titan engages a more extensive range of scientifi c disciplines than Next step inother seeking icy satellites. It isanswers an outstanding target to for comparative planetology, both with other satellites and with the terres- trial planets. Titan’s environment also enables uniquely affordable deployment of a wide array of instrumentation at the fundamentalsurface, in the atmosphere,questions and in orbit. Thus, the powerful complement of scientifi c tools necessary to understand such a complex system can actually be brought to bear. For example, in situ investigations such as seismic sensors and detailed What makes a planet orchemical moon analyses habitable? support and inform an orbital survey of this diverse target. Combinations of techniques provide more What chemical processes led robustto the constraints development on mysteries such as of Titan’s life? interior structure and atmospheric circulation. § Titan is an ideal destination to answer 1,000 Solar UV 0.0 these questions because it has the key N Energetic ingredients known to be necessary for life: 2 500 Diffusion Particles 0.01 4 CH 4 and Dust CH Energy: Sunlight, photochemistry Particles ar b Organic material: Abundant carbon and m , k e , r complex organics e 0.03 60 Condensate Haze essu r Solvents: Liquid water, as well as methane ltitud P A 0.1 C H Ice Ø Potential for organics to interact with liquid water at 40 2 6 the surFace, e.g., cryovolcanism, impact craters CH -N Clouds 4 2 0.3 Ø Potential for exchange of surface organics with vast 20 Rain Impacts interior ocean Ethane-methane CH4 H O/NH Melt 1.0 seas/lakes Venting 2 3 Organic Dunes 0 seas/lakes 1.5 Ø Earth-like world with an active methane cycle NH /H O Cryovolcanism? instead of Earth’s water cycle River Channels Organic Sediments 3 2 07-01121-03 • Liquid methane could support development (Lorenz, Waite, Leary, Reh, et al., 2007, Titan 07-01121 of alternate biological systems Explorer Flagship Mission Study Report) § Titan is an ocean world laboratory to investigate primitive chemistry and to search for biosignatures Space Exploration OPAG Meeting, Hampton, VA, 22 February 2018 Lunar and Planetary Science XLVIII (2017) 1958.pdf Thus the Dragonfly mission concept is a quadcop- acterize the habitability of Titan's environment, inves- ter designed to take advantage of Titan's environment tigate how far prebiotic chemistry has progressed, and to be able to sample materials and determine the sur- search for chemical signatures indicative of water- face composition in different geologic settings (Fig. 1). based and/or hydrocarbon-based life. Science Objectives: The compositions of the solid References: [1] Raulin F. et al. (2010) Titan's As- materials on Titan's surface are still essentially un- trobiology, in Titan from Cassini-Huygens Brown et known. Measuring the composition of materials in al. Eds. [2] Thompson W. R. and Sagan C. (1992), C. different geologic settings will reveal how far prebiotic Organic chemistry on Titan: Surface interactions , chemistry has progressed in environments that provide Symposium on Titan, ESA SP-338, 167-176. [3] Neish known key ingredients for life. Areas of particular in- C. D. et al. (2010) Astrobiology 10, 337-347.