Inorganic interpretation of luminescent materials encountered by the Perseverance rover on Mars

Creators: Scheller, Eva L.¹; Bosak, Tanja¹; McCubbin, Francis M.²; Williford, Kenneth³; Siljeström, Sandra⁴; Jakubek, Ryan S.²; Eckley, Scott A.²; Morris, Richard V.²; Bykov, Sergei V.⁵; Kizovski, Tanya⁶; Asher, Sanford⁵; Berger, Eve²; Bower, Dina M.⁷; Cardarelli, Emily L.⁸; Ehlmann, Bethany L.⁹; Fornaro, Teresa¹⁰; Fox, Allison²; Haney, Nikole²; Hand, Kevin¹¹; Roppel, Ryan⁵; Sharma, Sunanda¹¹; Steele, Andrew¹²; Uckert, Kyle¹¹; Yanchilina, Anastasia G.¹³; Beyssac, Olivier¹⁴; Farley, Kenneth A.⁹; Henneke, Jesper¹⁵; Heirwegh, Chris¹¹; Pedersen, David A. K.¹⁵; Liu, Yang¹¹; Schmidt, Mariek E.⁶; Sephton, Mark¹⁶; Shuster, David¹⁷; Weiss, Benjamin P.¹

1. Massachusetts Institute of Technology
2. Johnson Space Center
3. Blue Marble Space Institute of Science
4. RISE Research Institutes of Sweden
5. University of Pittsburgh
6. Brock University
7. University of Maryland, College Park
8. University of California, Los Angeles
9. California Institute of Technology
10. National Institute for Astrophysics
11. Jet Propulsion Lab
12. Carnegie Institution for Science
13. Impossible Sensing, LLC, St. Louis, MO 63118, USA.
14. Institute of Mineralogy, Materials Physics and Cosmochemistry
15. Technical University of Denmark
16. Imperial College London
17. University of California, Berkeley

Abstract

A major objective of the Mars 2020 mission is to sample rocks in Jezero crater that may preserve organic matter for later return to Earth. Using an ultraviolet Raman and luminescence spectrometer, the Perseverance rover detected luminescence signals with maximal intensities at 330 to 350 nanometers and 270 to 290 nanometers that were initially reported as consistent with organics. Here, we test the alternative hypothesis that the 330- to 350-nanometer and 270- to 290-nanometer luminescence signals trace Ce³⁺ in phosphate and silicate defects, respectively. By comparing the distributions of luminescence signals with the rover detections of x-ray fluorescence from P₂O₅ and Si-bearing materials, we show that, while an organic origin is not excluded, the observed luminescence can be explained by purely inorganic materials. These findings highlight the importance of eventual laboratory analyses to detect and characterize organic compounds in the returned samples.

Copyright and License

© 2024 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).

Acknowledgement

We thank the entire M2020 science and engineering operations team for their efforts that made this study possible. We extend our special thanks to the SHERLOC and PIXL science and engineering teams.

Funding

This work was supported by Heising-Simons 51 Pegasi B Fellowship #2389909 (E.L.S., T.B., and B.P.W.). The research was carried out, in part, at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004) (K.H., S.S., E.L.C., K.U., B.L.E., Y.L., and C.H.). This work was also funded by a Canadian Space Agency M2020 Participating Scientist grant (21EXPMAPS) (M.E.S.), the Mars 2020 Participating Scientist program (grant 80NSSC20K0238) (B.P.W.), and ASI/INAF agreement no. 2023-3-HH (T.F.).

Contributions

Conceptualization: E.L.S., T.B., F.M.M., B.P.W., and S.V.B. Methodology: E.L.S., T.B., F.M.M., B.P.W., R.S.J., D.A.K.P., and C.H. Investigation: All authors. Visualization: E.L.S., T.B., B.P.W., F.M.M., and R.S.J. Supervision: E.L.S., T.B., B.P.W., and K.H. Writing—original draft: E.L.S., T.B., B.P.W., F.M.M., and R.S.J. Writing—review and editing: All authors.

Data Availability

SHERLOC and PIXL data are available on the Mars 2020 Planetary Data System (PDS) under the SHERLOC bundle (DOI: 10.17189/1522643) and the PIXL bundle (DOI: 10.17189/1522645). A full list of specific data files and their description can be found in the Supplement Materials. All laboratory spectra are made available on the Zenodo link: 10.5281/zenodo.10946380. All other data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.

Supplemental Material

Supplementary Text; Figs. S1 to S13; Tables S1 to S3

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