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Implantation of Martian atmospheric ions within the regolith of Phobos

Abstract

When a planet has an orbiting moon, atoms and molecules that escape the planetary atmosphere as ions and are accelerated into space may be implanted and preserved inside the moon’s surface. Here, we determine the long-term averaged anisotropy of ions escaping the atmosphere of Mars and impacting its moon Phobos from more than four years of in situ ion observations. These measurements are used to quantify an estimate of the average flux of ions that has been impacting each location on Phobos over geologic timescales. We find that the flux of bombarding Martian ions is highly asymmetric on the moon’s surface, as the nearside of Phobos sees a flux higher by a factor of 15 to 100 than its farside. We show that a first consequence of this is that Martian atmospheric oxygen, carbon, nitrogen and argon atoms are implanted and may be preserved inside the uppermost hundreds of nanometres of Phobos’s nearside regolith grains, which may be brought back to Earth by future sample return missions. The second effect is that alteration of the regolith properties is asymmetric on Phobos’s surface, as Martian ions accelerate weathering of the nearside by a factor of ~2.

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Fig. 1: The long-term averaged flux of solar wind and Martian ions that impact the surface of Phobos, as observed by MAVEN.
Fig. 2: Implantation rate inside Phobos’s regolith grains of exogenous atoms transported by impacting ions.
Fig. 3: Collisional energy deposited inside Phobos’s regolith grains by impacting ions.

Data availability

MAVEN/STATIC Level 2 data are publicly available on the NASA Planetary Data System website (https://pds-ppi.igpp.ucla.edu/) in the volume named ‘MAVEN-Mars-STATIC’. The long-term average of STATIC directionally resolved fluxes at the orbit of Phobos computed in this article, the ion precipitation maps on the surface of Phobos and the computed implantation rate and deposited collisional energy depth profiles have been delivered to the published Figshare repository: https://doi.org/10.6084/m9.figshare.12939872.

Code availability

The SRIM software is accessible online at http://www.srim.org/.

References

  1. 1.

    Ozima, M. et al. Terrestrial nitrogen and noble gases in lunar soils. Nature 436, 655–659 (2005).

    Article  Google Scholar 

  2. 2.

    Poppe, A. R., Fillingim, M. O., Halekas, J. S., Raeder, J. & Angelopoulos, V. ARTEMIS observations of terrestrial ionospheric molecular ion outflow at the Moon. Geophys. Res. Lett. 43, 6749–6758 (2016).

    Article  Google Scholar 

  3. 3.

    Terada, K. et al. Biogenic oxygen from Earth transported to the Moon by a wind of magnetospheric ions. Nat. Astron. 1, 0026 (2017).

    Article  Google Scholar 

  4. 4.

    Geiss, J. & Bochsler, P. in The Sun in Time (eds. Sonnett, C. P. et al.) 98–117 (Univ. Arizona Press, 1991).

  5. 5.

    Ozima, M., Yin, Q. Z., Podosek, F. A. & Miura, Y. N. Toward understanding early Earth evolution: prescription for approach from terrestrial noble gas and light element records in lunar soils. Proc. Natl Acad. Sci. USA 105, 17654–17658 (2008).

    Article  Google Scholar 

  6. 6.

    Christon, S. P. et al. Energetic atomic and molecular ions of ionospheric origin observed in distant magnetotail flow‐reversal events. Geophys. Res. Lett. 21, 3023–3026 (1994).

    Article  Google Scholar 

  7. 7.

    Wei, Y. et al. Implantation of Earth’s atmospheric ions into the nearside and farside lunar soil: implications to geodynamo evolution. Geophy. Res. Lett. 47, e2019GL086208 (2020).

    Google Scholar 

  8. 8.

    Pieters, C. M., Murchie, S., Thomas, N. & Britt, D. Composition of surface materials on the moons of Mars. Planet. Space Sci. 102, 144–151 (2014).

    Article  Google Scholar 

  9. 9.

    Schmedemann, N., Michael, G. G., Ivanov, B. A., Murray, J. B. & Neukum, G. The age of Phobos and its largest crater, Stickney. Planet. Space Sci. 102, 152–163 (2014).

    Article  Google Scholar 

  10. 10.

    Ramsley, K. R. & Head, J. W. The Stickney Crater ejecta secondary impact crater spike on Phobos: implications for the age of Stickney and the surface of Phobos. Planet. Space Sci. 138, 7–24 (2017).

    Article  Google Scholar 

  11. 11.

    Hu, X., Oberst, J. & Willner, K. Equipotential figure of Phobos suggests its late accretion near 3.3 Mars radii. Geophys. Res. Lett. 47, e2019GL085958 (2020).

    Google Scholar 

  12. 12.

    Keller L. P. and Zhang Z. Rates of space weathering in lunar soils. In Proc. Space Weathering of Airless Bodies: An Integration of Remote Data, Laboratory Experiments and Sample Analysis Workshop 2056 (LPI, 2015).

  13. 13.

    Ballouz, R. L., Baresi, N., Crites, S. T., Kawakatsu, Y. & Fujimoto, M. Surface refreshing of Martian moon phobos by orbital eccentricity-driven grain motion. Nat. Geosci. 12, 229–234 (2019).

    Article  Google Scholar 

  14. 14.

    Ramstad, R., Barabash, S., Futaana, Y., Nilsson, H. & Holmström, M. Ion escape from Mars through time: an extrapolation of atmospheric loss based on 10 years of Mars Express measurements. J. Geophys. Res. Planets 123, 3051–3060 (2018).

    Article  Google Scholar 

  15. 15.

    Bogard, D. D. & Garrison, D. H. Relative abundances of argon, krypton, and xenon in the Martian atmosphere as measured in Martian meteorites. Geochim. Cosmochim. Acta 62, 1829–1835 (1998).

    Article  Google Scholar 

  16. 16.

    Ott, U., Swindle, T. D. & Schwenzer, S. P. in Volatiles in the Martian Crust (eds. Filiberto, J. & Schwenzer, S. P.) 35–70 (Elsevier, 2019).

  17. 17.

    Bills, B. G., Neumann, G. A., Smith, D. E. & Zuber, M. T. Improved estimate of tidal dissipation within Mars from MOLA observations of the shadow of Phobos. J. Geophys. Res. Planets 110, E07004 (2005).

    Google Scholar 

  18. 18.

    Quillen, A. C., Lane, M., Nakajima, M. & Wright, E. Excitation of tumbling in Phobos and Deimos. Icarus 340, 113641 (2020).

    Article  Google Scholar 

  19. 19.

    Szabo, P. et al. Dynamic potential sputtering of lunar analog material by solar wind ions. Astrophys. J. 891, 100 (2020).

    Article  Google Scholar 

  20. 20.

    Poppe, A. R., Farrell, W. M. & Halekas, J. S. Formation timescales of amorphous rims on lunar grains derived from ARTEMIS observations. J. Geophys. Res. Planets 123, 37–46 (2018).

    Article  Google Scholar 

  21. 21.

    Nénon, Q. et al. Phobos surface sputtering as inferred from MAVEN ion observations. J. Geophys. Res. Planets 124, 3385–3401 (2019).

    Article  Google Scholar 

  22. 22.

    McFadden, J. P. et al. MAVEN suprathermal and thermal ion composition (STATIC) instrument. Space Sci. Rev. 195, 199–256 (2015).

    Article  Google Scholar 

  23. 23.

    Dong, Y. et al. Seasonal variability of Martian ion escape through the plume and tail from MAVEN observations. J. Geophys. Res. Space Phys. 122, 4009–4022 (2017).

    Article  Google Scholar 

  24. 24.

    Rahmati, A. et al. MAVEN measured oxygen and hydrogen pickup ions: probing the Martian exosphere and neutral escape. J. Geophys. Res. Space Phys. 122, 3689–3706 (2017).

    Article  Google Scholar 

  25. 25.

    Ziegler, J. F. SRIM-2013 (2013); http://www.srim.org

  26. 26.

    Grimberg, A. et al. Solar wind neon from Genesis: implications for the lunar noble gas record. Science 314, 1133–1135 (2006).

    Article  Google Scholar 

  27. 27.

    Mortimer, J., Verchovsky, A. B. & Anand, M. Predominantly non-solar origin of nitrogen in lunar soils. Geochim. Cosmochim. Acta 193, 36–53 (2016).

    Article  Google Scholar 

  28. 28.

    Larson, D. E. et al. The MAVEN solar energetic particle investigation. Space Sci. Rev. 195, 153–172 (2015).

    Article  Google Scholar 

  29. 29.

    Jakosky, B. M. et al. MAVEN observations of the response of Mars to an interplanetary coronal mass ejection. Science 350, aad0210 (2015).

    Article  Google Scholar 

  30. 30.

    Inui, S. et al. Statistical study of heavy ion outflows from Mars observed in the Martian-induced magnetotail by MAVEN. J. Geophys. Res. Space Phys. 124, 5482–5497 (2019).

    Article  Google Scholar 

  31. 31.

    Jakosky, B. M. et al. Mars’ atmospheric history derived from upper-atmosphere measurements of 38Ar/36Ar. Science 355, 1408–1410 (2017).

    Article  Google Scholar 

  32. 32.

    Jakosky, B. M. et al. Loss of the Martian atmosphere to space: present-day loss rates determined from MAVEN observations and integrated loss through time. Icarus 315, 146–157 (2018).

    Article  Google Scholar 

  33. 33.

    Farrell, W. M., Hurley, D. M., Esposito, V. J., McLain, J. L. & Zimmerman, M. I. The statistical mechanics of solar wind hydroxylation at the Moon, within lunar magnetic anomalies, and at Phobos. J. Geophys. Res. Planets 122, 269–289 (2017).

    Article  Google Scholar 

  34. 34.

    Pieters, C. M. & Noble, S. K. Space weathering on airless bodies. J. Geophys. Res. Planets 121, 1865–1884 (2016).

    Article  Google Scholar 

  35. 35.

    Zeitlin, C. et al. Mars Odyssey measurements of galactic cosmic rays and solar particles in Mars orbit, 2002-2008. Space Weather 8, S00E06 (2010).

    Article  Google Scholar 

  36. 36.

    Leblanc, F. et al. On Mars’s atmospheric sputtering after MAVEN’s first Martian year of measurements. Geophys. Res. Lett. 45, 4685–4691 (2018).

    Article  Google Scholar 

  37. 37.

    Mura, A., Milillo, A., Orsini, S., Kallio, E. & Barabash, S. Energetic neutral atoms at Mars 2. Imaging of the solar wind–Phobos interaction. J. Geophys. Res. Space Phys. 107, 1278 (2002).

    Article  Google Scholar 

  38. 38.

    Wang, X. D. et al. Energy spectral properties of hydrogen energetic neutral atoms emitted from the dayside atmosphere of Mars. J. Geophys. Res. Space Phys. 124, 4104–4113 (2019).

    Article  Google Scholar 

  39. 39.

    Fowler, C. M. et al. The modulation of solar wind hydrogen deposition in the Martian atmosphere by foreshock phenomena. J. Geophys. Res. Space Phys. 124, 7086–7097 (2019).

    Article  Google Scholar 

  40. 40.

    Andersson, L. et al. Dust observations at orbital altitudes surrounding Mars. Science 350, aad0398 (2015).

    Article  Google Scholar 

  41. 41.

    Hyodo, R., Kurosawa, K., Genda, H., Usui, T. & Fujita, K. Transport of impact ejecta from Mars to its moons as a means to reveal Martian history. Sci. Rep. 9, 19833 (2019).

    Article  Google Scholar 

  42. 42.

    Füri, E., Marty, B. & Assonov, S. S. Constraints on the flux of meteoritic and cometary water on the Moon from volatile element (N–Ar) analyses of single lunar soil grains, Luna 24 core. Icarus 218, 220–229 (2012).

    Article  Google Scholar 

  43. 43.

    Poppe, A. R. & Curry, S. M. Martian planetary heavy ion sputtering of Phobos. Geophys. Res. Lett. 41, 6335–6341 (2014).

    Article  Google Scholar 

  44. 44.

    Christoffersen, R., Keller, L. P. & Dukes, C. The role of solar wind ion processing in space weathering of olivine: unraveling the paradox of laboratory irradiation results compared to observations of natural samples. In Proc. 51st Lunar and Planetary Science Conference 2147 (LPI, 2020).

  45. 45.

    Christoffersen, R. & Keller, L. Space radiation processing of sulfides and silicates in primitive solar systems material: comparative insights from in situ TEM ion irradiation experiments. Meteorit. Planet. Sci. 461, 950–969 (2011).

    Article  Google Scholar 

  46. 46.

    Brain, D. A. et al. The spatial distribution of planetary ion fluxes near mars observed by MAVEN. Geophys. Res. Lett. 42, 9142–9148 (2015).

    Article  Google Scholar 

  47. 47.

    Harada, Y. et al. Marsward and tailward ions in the near‐Mars magnetotail: MAVEN observations. Geophys. Res. Lett. 42, 8925–8932 (2015).

    Article  Google Scholar 

  48. 48.

    Farrell, W. M. et al. Anticipated electrical environment at Phobos: nominal and solar storm conditions. Adv. Space Res. 62, 2199–2212 (2018).

    Article  Google Scholar 

  49. 49.

    Szabo, P. et al. Solar wind sputtering of wollastonite as a lunar analogue material—comparisons between experiments and simulation. Icarus 314, 98–105 (2018).

    Article  Google Scholar 

  50. 50.

    Hofsäss, H., Zhang, K. & Mutzke, A. Simulation of ion beam sputtering with SDTrimSP, TRIDYN and SRIM. Appl. Surf. Sci. 310, 134–141 (2014).

    Article  Google Scholar 

  51. 51.

    Schaible, M. J. et al. Solar wind sputtering rates of small bodies and ion mass spectrometry detection of secondary ions. J. Geophys. Res. Planets 122, 1968–1983 (2017).

    Article  Google Scholar 

  52. 52.

    Gray, M. D. & Edmunds, M. G. Modification of dust-grain structure by sputtering. Mon. Not. R. Astron. Soc. 349, 491–502 (2004).

    Article  Google Scholar 

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Acknowledgements

Q.N. and A.R.P. acknowledge funding from the NASA Solar System Research Virtual Institute via both the DREAM2 Team, grant #NNX14AG16A, and the LEADER team, grant #80NSSC20M0060. A.R. and J.P.M. acknowledge funding by NASA through MAVEN Project subcontracts managed by LASP, University of Colorado under the direction of the MAVEN principal investigator, B. M. Jakosky. The MAVEN mission has been made possible through NASA sponsorship and the dedicated efforts of NASA Goddard Space Flight Center, LASP, Lockheed project management and the MAVEN Technical and Science Teams. We thank A. Quillen (University of Rochester) for discussions on the tumbling of Phobos and H. Hofsäss (University of Göttingen) and W. Weber (University of Tennessee) for discussions on the use of the SRIM simulation tool.

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Contributions

Q.N. compiled and analysed MAVEN/STATIC data at Phobos’s orbit, created ion precipitation maps on Phobos’s surface, ran SRIM simulations and wrote the article. A.R.P. provided expertise and many fruitful discussions on space weathering of airless bodies and SRIM simulations. A.R.P. also thoroughly proofed the first draft of this article. A.R. provided expertise and discussion on the extended exosphere of Mars, the ion environment at Mars, the STATIC instrument and the use of MAVEN data files and associated software tools. In addition, A.R. shared software routines he previously developed for the long-term and statistical analysis of pickup ions at Mars, parts of which have been used by Q.N. to develop the analysis software used in this study. J.P.M. is the principal investigator of the STATIC experiment and provided critical discussions on the instrument observations and known caveats. All authors have read and endorsed the content of the article.

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Correspondence to Q. Nénon.

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Peer review information Nature Geoscience thanks Roy Christoffersen and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Tamara Goldin; Stefan Lachowycz.

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Supplementary Information

Supplementary Methods 1–5, Discussion 1 and Figs. 1–10.

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Nénon, Q., Poppe, A.R., Rahmati, A. et al. Implantation of Martian atmospheric ions within the regolith of Phobos. Nat. Geosci. 14, 61–66 (2021). https://doi.org/10.1038/s41561-020-00682-0

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