OSIRIS-REx Returned a Pristine Sample of Asteroid Bennu: Takeaways from the Mission’s Contamination Control and Knowledge ProgramOPEN ACCESS
Jason P. Dworkin, Scott A. Sandford, Nicole G. Lunning, Kevin Righter, Charles C. Lorentson, Daniel P. Glavin, Kathie L. Thomas-Keprta, Loan Le, Catherine M. Corrigan, Timothy J. McCoy, Edward B. Bierhaus, Jose C. Aponte, Angel Mojarro, Hannah L. McLain, Eric T. Parker, Denise K. Buckner, Frédéric Seguin, Radford L. Perry, Heather V. Graham, Havishk Tripathi, Pierre Haenecour, Piers Koefoed, Kun Wang, Cody Schultz, Takahiro Hiroi, Ralph E. Milliken, Simon J. Clemett, Bumsoo Kim, Christopher J. Snead, Eve L. Berger, Michael Liss, Jessica J. Barnes, Sandra Freund, Zoe A. Wilson, Ryan D. Dubisher, Natasha V. Almeida, Kimberly K. Allums, Erika H. Blumenfeld, Joseph E. Aebersold, Rachel C. Funk, Carla P. Gonzales, Julia L. Plummer, Maritza Montoya, Daniel J. Rohmer, Erika V. Rivera, Jannatul Ferdous, Gabriel C. Garcia, Melissa Rodriguez, Jose L. Ponce, Ronald Bastien, Wayland D. Connelly, Jemma Davidson, Marghaleray Amini, Vivian Lai, Dominique Weis, Josh Wimpenny, Jan Render, Gregory A. Brennecka, Yoshihiro Furukawa, Toshiki Koga, Yoshinori Takano, Hiroshi Naraoka, Yasuhiro Oba, Kenneth J. Domanik, Yao-Jen Chang, Zoe Zeszut, Thomas J. Zega, George D. Cody, Conel M. O’D. Alexander, Ian A. Franchi, Monica M. Grady, Danielle N. Simkus, Jamie E. Elsila, Philippe Schmitt-Kopplin, Allison A. Baczynski, Katherine H. Freeman, Amy E. Hofmann, Aaron S. Burton, Lindsay P. Keller, Sara S. Russell, Anjani T. Polit, Francis M. McCubbin, Harold C. Connolly Jr., Dante S. Lauretta
submitted to Space Science Reviews, 10 September 2026
“NASA’s OSIRIS-REx mission had the objective of delivering a pristine sample from asteroid (101955) Bennu to Earth for scientific analysis–where “pristine” signifies the absence of foreign materials that could affect sample measurements. OSIRIS-REx returned 121.6 g of regolith in September 2023; this study documents the systematic investigation of suspected contaminants encountered during the mission’s sample analysis phase. Most suspected contaminants did not originate from the spacecraft or sample curation. Some were introduced during laboratory analyses, reinforcing the importance of procedural blanks and a strategic approach to sharing samples across laboratories with different analytical targets. Several suspected contaminants, such as phosphate and sodium fluoride particles, were ultimately identified as indigenous to Bennu, highlighting the critical role of contamination knowledge in preventing the dismissal of valuable scientific data. We find that the returned sample meets the definition of pristine, except for an isolated 1.24% (by mass) that escaped the sample container and was thereby contaminated with spacecraft particulates. These findings demonstrate the effectiveness of systematically applied contamination science and engineering practices and provide lessons and approaches to help maximize the scientific integrity of future planetary sample return missions.”
