Radar for Europa Assessment and Sounding: Ocean to Near-Surface (REASON)

Creators: Blankenship, Donald D.; Moussessian, Alina; Chapin, Elaine; Young, Duncan A.; Wesley Patterson, G.; Plaut, Jeffrey J.; Freedman, Adam P.; Schroeder, Dustin M.; Grima, Cyril; Steinbrügge, Gregor; Soderlund, Krista M.; Ray, Trina; Richter, Thomas G.; Jones-Wilson, Laura; Wolfenbarger, Natalie S.; Scanlan, Kirk M.; Gerekos, Christopher; Chan, Kristian; Seker, Ilgin; Haynes, Mark S.; Barr Mlinar, Amy C.; Bruzzone, Lorenzo; Campbell, Bruce A.; Carter, Lynn M.; Elachi, Charles¹; Gim, Yonggyu; Hérique, Alain; Hussmann, Hauke; Kofman, Wlodek; Kurth, William S.; Mastrogiuseppe, Marco; McKinnon, William B.; Moore, Jeffrey M.; Nimmo, Francis; Paty, Carol; Plettemeier, Dirk; Schmidt, Britney E.; Zolotov, Mikhail Y.; Schenk, Paul M.; Collins, Simon; Figueroa, Harry; Fischman, Mark; Tardiff, Eric; Berkun, Andy; Paller, Mimi; Hoffman, James P.; Kurum, Andy; Sadowy, Gregory A.; Wheeler, Kevin B.; Decrossas, Emmanuel; Hussein, Yasser; Jin, Curtis; Boldissar, Frank; Chamberlain, Neil; Hernandez, Brenda; Maghsoudi, Elham; Mihaly, Jonathan; Worel, Shana; Singh, Vik; Pak, Kyung; Tanabe, Jordan; Johnson, Robert; Ashtijou, Mohammad; Alemu, Tafesse; Burke, Michael; Custodero, Brian; Tope, Michael C.; Hawkins, David; Aaron, Kim; Delory, Gregory T.; Turin, Paul S.; Kirchner, Donald L.; Srinivasan, Karthik; Xie, Julie; Ortloff, Brad; Tan, Ian; Noh, Tim; Clark, Duane; Duong, Vu; Joshi, Shivani; Lee, Jeng; Merida, Elvis; Akbar, Ruzbeh; Duan, Xueyang; Fenni, Ines; Sanchez-Barbetty, Mauricio; Parashare, Chaitali; Howard, Duane C.; Newman, Julie; Cruz, Marvin G.; Barabas, Neil J.; Amirahmadi, Ahmadreza; Palmer, Brendon; Gawande, Rohit S.; Milroy, Grace; Roberti, Rick; Leader, Frank E.; West, Richard D.; Martin, Jan; Venkatesh, Vijay; Adumitroaie, Virgil; Rains, Christine; Quach, Cuong; Turner, Jordi E.; O'Shea, Colleen M.; Kempf, Scott D.; Ng, Gregory; Buhl, Dillon P.; Urban, Timothy J.

1. California Institute of Technology

Abstract

AbstractThe 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.

Copyright and License

© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Acknowledgement

This work was supported by NASA through the Europa Clipper Project (80NM0018F0615). The REASON radar was designed, built, and tested at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). REASON science was supported by a contract with Marshall Space Flight Center (NNM16AA26C). This is UTIG contribution 3970. The contributions of Mauricio Sanchez-Barbetty, Duane C. Howard, and Julie Newman were made during their time as employees of the Jet Propulsion Laboratory. We acknowledge the support of the NASA Instrument Concepts for Europa Exploration (ICEE) program (13-ICEE13-18) for the development and field validation of techniques ultimately employed by the REASON investigation and thank the G. Unger Vetlesen foundation for their contribution to validation of terrestrial models for Europa’s ice shell. We would like to thank L3Harris Cincinnati Electronics Corporation and Wenzel Associates for their dedication in developing and building the DPUs and Synthesizers, respectively. Additionally, we would like to extend our gratitude to James Chinn, Wousik Kim, Allen Andersen, Dennis Thorbourn, and Eduardo Martin of JPL as well as Stephen Brown, Kenneth O’Connor, and Robert Meloy of GSFC for their invaluable help with IESD analysis and testing. We also want to thank the Space Simulator Laboratory at APL for their support during the cryogenics test campaign. Finally, we are grateful to Sean Peters, Anna Broome, and Thomas Teisberg for their feedback on this manuscript.

Conflict of Interest

The authors have no competing interests to declare that are relevant to the content of this article.

Additional Information

Europa Clipper: A Mission to Explore Ocean World Habitability

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