Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON)
Donald D. Blankenship, Alina Moussessian, Elaine Chapin, D. A. Young, G. W. Patterson, J. J. Plaut, A. P. Freedman, Dustin M. Schroeder, C. Grima, Gregor Steinbrügge, K. M. Soderlund, T. L. Ray, Thomas G. Richter, Laura Jones-Wilson, Natalie S. Wolfenbarger, Kirk M. Scanlan, Christopher Gerekos, Kristian Chan, Ilgın Şeker, Mark Haynes, Amy C. Barr Mlinar, Lorenzo Bruzzone, B. A. Campbell, Lynn M. Carter, C. Elachi, Yonggyu Gim, Alain Hèrique, Hauke Hußmann, W. Kofman, W. S. Kŭrth, Marco Mastrogiuseppe, W. B. McKinnon, J. M. Moore, F. Nimmo, C. S. Paty, Dirk Plettemeier, B. E. Schmidt, M. Yu. Zolotov, P. Schenk, Simon Collins, H. Figueroa, M.A. Fischman, Eric Tardiff, Andy Berkun, Mimi Paller, James P. Hoffman, Andy Kurum, G. Sadowy, Kevin Wheeler, Emmanuel Decrossas, Yasser A. Hussein, Curtis Jin, F. Boldissar, Neil Chamberlain, Brenda Hernandez, Elham Maghsoudi, Jonathan Mihaly, Shana C. Worel, Vik Singh, Kyung Pak, Jordan Tanabe, R. E. Johnson, Mohammad Ashtijou, Tafesse Alemu, Michael Burke, Brian Custodero, Michael Tope, David Hawkins, Kim Aaron, G. T. Delory, P. Turin, D. L. Kirchner, K.N. Srinivasan, Julie Xie, Bradley Ortloff, Ian Tan, Tim Noh, Duane Clark, Vũ Dương, Shivani Joshi, Jeng Lee, Elvis Merida, Ruzbeh Akbar, Xueyang Duan, Ines Fenni, Mauricio Sánchez-Barbetty, Chaitali Parashare, Duane C. Howard, Julie Newman, Marvin G. Cruz, Neil J. Barabas, Ahmadreza Amirahmadi, Brendon Palmer, Rohit Gawande, Grace Milroy, Rick Roberti, F. Leader, Richard West, Jan Martin, Vijay Venkatesh
Abstract
Abstract The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice–ocean interface, characterizing the ice shell’s global structure, and constraining the amplitude of Europa’s radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry , reflectometry , sounding , interferometry , plasma characterization , and ranging . Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and – in concert with other instruments on Europa Clipper – help to investigate whether Europa is a habitable world.