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Lunar soil hydration constrained by exospheric water liberated by meteoroid impacts


Analyses of samples from the Apollo missions suggest that the Moon formed devoid of native water. However, recent observations by Cassini, Deep Impact, Lunar Prospector and Chandrayaan-1 indicate the existence of an active water cycle on the Moon. Here we report observations of this water cycle, specifically detections of near-surface water released into the lunar exosphere by the Neutral Mass Spectrometer on the Lunar Atmosphere and Dust Environment Explorer. The timing of 29 water releases is associated with the Moon encountering known meteoroid streams. The intensities of these releases reflect the convoluted effects of the flux, velocity and impact location of the parent streams. We propose that four additional detected water releases represent the signature of previously undiscovered meteoroid streams. We show that water release from meteoroid impacts is indicative of a lunar surface that has a desiccated soil layer of several centimetres on top of uniformly hydrated soil. We infer that the Moon is currently in the process of losing water that was either delivered long ago or present at its formation.

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Fig. 1: Identification of meteoroid streams in NMS-recorded water events.
Fig. 2: Comparison between NMS water event observations and soil hydration models.
Fig. 3: The lunar water cycle as suggested by the NMS observations.

Data availability

The NMS data supporting this Article are publicly available from the Planetary Data System (

Code availability

The Matlab scripts used for the analyses and modelling described in this study can be obtained from the corresponding author on reasonable request.


  1. Taylor, S. R. Lunar Science: A Post-Apollo View (Pergamon, 1975).

  2. Papike, J. J., Taylor L. & Simon, S. in The Lunar Source Book (eds Heiken, G.H. et al.) 121–182 (Cambridge Univ. Press, 1991).

  3. Lucey, P. et al. Understanding the lunar surface and space–Moon interactions. Rev. Miner. Geochem. 60, 83–219 (2006).

    Article  Google Scholar 

  4. Shearer, C. K. et al. Thermal and magmatic evolution of the Moon. Rev. Miner. Geochem. 60, 365–518 (2006).

    Article  Google Scholar 

  5. Clark, R. N. Detection of adsorbed water and hydroxyl on the Moon. Science 326, 562–564 (2009).

    Article  Google Scholar 

  6. Sunshine, J. M. et al. Temporal and spatial variability of lunar hydration as observed by the Deep Impact spacecraft. Science 326, 565–568 (2009).

    Article  Google Scholar 

  7. Pieters, C. M. et al. Character and spatial distribution of OH/H2O on the surface of the Moon seen by M3 on Chandrayaan-1. Science 326, 568–572 (2009).

    Article  Google Scholar 

  8. Feldman, W. C. et al. Fluxes of fast and epithermal neutrons from lunar prospector: evidence for water ice at the lunar poles. Science 218, 1496–1500 (1998).

    Article  Google Scholar 

  9. Mitrofanov, I. G. et al. Mapping of the lunar south pole using the LRO neutron detector experiment LEND. Science 330, 483–486 (2010).

    Article  Google Scholar 

  10. Colaprete, A. et al. Detection of water in the LCROSS ejecta plume. Science 330, 463–468 (2010).

    Article  Google Scholar 

  11. Watson, K., Murray, B. & Brown, H. On the possible presence of ice on the Moon. J. Geophys. Res. 66, 1598–1600 (1961).

    Article  Google Scholar 

  12. Arnold, J. R. Ice in the lunar polar regions. J. Geophys. Res. 84, 5659–5668 (1979).

    Article  Google Scholar 

  13. Housley, R. M., Cirlin, E. H. & Grant, R. W. Characterization of fines from the Apollo 16 site. Geochim. Cosmochim. Acta 3, 2623–2642 (1974).

    Google Scholar 

  14. Urey, H. C. The Planets, Their Origin and Development (Yale Univ. Press, 1952).

  15. Crider, D. H. & Vondrak, R. R. Space weathering effects on lunar cold trap deposits. J. Geophys. Res. 108, 5078 (2003).

    Article  Google Scholar 

  16. Hurley, D. H. & Benna, M. Simulations of lunar exospheric water events from meteoroid impacts. Planet. Space Sci. 162, 148–156 (2017).

    Article  Google Scholar 

  17. Prem, P., Artemieva, N. A., Goldstein, D. B., Varghese, P. L. & Trafton, M. Transport of water in a transient impact-generated lunar atmosphere. Icarus 255, 148–158 (2015).

    Article  Google Scholar 

  18. Lawrence, D. J. et al. Bulk hydrogen abundances in the lunar highlands: measurements from orbital neutron data. Icarus 255, 127–135 (2015).

    Article  Google Scholar 

  19. Li, S. & Milliken, R. E. Water on the surface of the Moon as seen by the Moon Mineralogy Mapper: distribution, abundance, and origins. Sci. Adv. 3, e1701471 (2017).

    Article  Google Scholar 

  20. Elphic, R. C. et al. The Lunar Atmosphere and Dust Environment Explorer mission. Space Sci. Rev. 185, 3–25 (2014).

    Article  Google Scholar 

  21. Mahaffy, P. M. et al. The Neutral Mass Spectrometer on the Lunar Atmosphere and Dust Environment Explorer mission. Space Sci. Rev. 185, 27–61 (2014).

    Article  Google Scholar 

  22. Benna, M., Mahaffy, P. R., Halekas, J. S., Elphic, R. C. & Delory, G. T. Variability of helium, neon, and argon in the lunar exosphere as observed by the LADEE. Geophys. Res. Lett. 42, 3723–3729 (2015).

    Article  Google Scholar 

  23. Hodges, R. R. Jr Methane in the lunar exosphere: implications for solar wind carbon escape. Geophys. Res. Lett. 43, 6742–6748 (2016).

    Article  Google Scholar 

  24. Halekas, J. S. et al. Detections of lunar exospheric ions by the LADEE neutral mass spectrometer. Geophys. Res. Lett. 42, 5162–5169 (2015).

    Article  Google Scholar 

  25. Jopeka, T. J. & Kaňuchová, Z. IAU Meteor Data Center—the shower database: a status report. Planet. Space Sci. 143, 3–6 (2017).

    Article  Google Scholar 

  26. Horányi, M. et al. A permanent, asymmetric dust cloud around the Moon. Nature 522, 324–326 (2015).

    Article  Google Scholar 

  27. Szalay, J. R. & Horányi, M. Detecting meteoroid streams with an in-situ dust detector above an airless body. Icarus 275, 221–231 (2016).

    Article  Google Scholar 

  28. International Meteor Organization (accessed 18 January 2018);

  29. Vasavada, A. R. et al. Lunar equatorial surface temperatures and regolith properties from the Diviner Lunar Radiometer Experiment. J. Geophys. Res. 117, E00H18 (2012).

    Article  Google Scholar 

  30. Hayne, P. O. et al. Global regolith thermophysical properties of the Moon from the Diviner Lunar Radiometer Experiment. J. Geophys. Res. 122, 2371–2400 (2017).

    Article  Google Scholar 

  31. Schorghofer, N. & Aharonson, O. The lunar thermal ice pump. Astrophys. J. 788, 169 (2014).

    Article  Google Scholar 

  32. Housley, R. M., Grant, R. W. & Paton, N. E. Origin and characteristics of excess Fe metal in lunar glass welded aggregates. Geochim. Cosmochim. Acta 3, 2737–2749 (1973).

    Google Scholar 

  33. Mazarico, E. et al. Illumination conditions of the lunar polar regions using LOLA topography. Icarus 211, 1066–1081 (2011).

    Article  Google Scholar 

  34. Grün, E., Zook, H. A., Fetchtig, H. & Giese, R. H. Collisional balance of the meteoritic complex. Icarus 62, 244–272 (1985).

    Article  Google Scholar 

  35. Halliday, I., Griffin, A. A. & Blackwell, A. T. Detailed data for 259 fireballs from the Canadian camera network and inferences concerning the influx of large meteoroids. Meteorit. Planet. Sci 31, 185–217 (1996).

    Article  Google Scholar 

  36. Brown, P., Spalding, R. E., ReVelle, D. O., Tagliaferri, E. & Wordenk, S. P. The flux of small near-earth objects colliding with the Earth. Nature 420, 294–296 (2002).

    Article  Google Scholar 

  37. Steyaert, C. Calculating the solar longitude 2000.0. WGN 19, 31–34 (1991).

    Google Scholar 

  38. Melosh, H. J. Impact Cratering: A Geologic Process 60–65 (Oxford Univ. Press, 1989).

  39. Molau, S. et al. Results of the IMO Video Meteor Network—December 2015. WGN 44, 51–56 (2015).

    Google Scholar 

  40. Jenniskens, P. Meteor stream activity. Astron. Astrophys. 287, 990–1013 (1994).

    Google Scholar 

  41. Holsapple, K. A. The scaling of impact processes in planetary science. Annu. Rev. Earth Planet. Sci. 21, 333–373 (1993).

    Article  Google Scholar 

  42. Hanner, M. & Zolensky, M. in Astromineralogy (ed. Henning, T.) 203–232 (Springer, 2010).

  43. Cintala, M. J. Impact-induced thermal effects in the lunar and mercurian regoliths. J. Geophys. Res. 97, 947–973 (1992).

    Article  Google Scholar 

  44. Lange, M. A., Lambert, P. & Ahrens, T. J. Shock effects on hydrous minerals and implications for carbonaceous meteorites. Geochim. Cosmochim. Acta 48, 1715–1726 (1985).

    Article  Google Scholar 

  45. Poston, M. J. et al. Temperature programmed desorption studies of water interactions with Apollo lunar samples 12001 and 72501. Icarus 255, 24–29 (2015).

    Article  Google Scholar 

  46. Slyuta, E. N. et al. Application of thermodesorption mass spectrometry for studying proton water formation in the lunar regolith. Geochem. Int. 55, 27–37 (2017).

    Article  Google Scholar 

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The LADEE/NMS investigation was supported by NASA. Tests and calibrations were completed at the Planetary Environment Laboratory of NASA’s Goddard Space Flight Center. We thank R. R. Vondrak, W. M. Farrell, R. M. Killen and T. H. Morgan for insightful discussions and comments. We also thank E. Raaen for his calibration support, E. Zubritsky for editing and J. Friedlander for graphics assistance.

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Authors and Affiliations



M.B. directed the data analysis and was primarily responsible for writing the article. D.M.H. developed the exosphere model and helped analyse and interpret the NMS data. T.J.S. conducted the correlation analysis between meteoroid streams and the NMS observations. P.R.M. is the principal investigator of the instrument and contributed to instrument calibration and data analysis. R.C.E. is the LADEE project scientist, developed the LADEE observation plans for the NMS, coordinated data acquisition with other LADEE instruments and contributed to data analysis.

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Correspondence to M. Benna.

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Supplementary Information

Supplementary Materials 1–6, Supplementary Figs. 1–17 and Supplementary Tables 1 and 2.

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Benna, M., Hurley, D.M., Stubbs, T.J. et al. Lunar soil hydration constrained by exospheric water liberated by meteoroid impacts. Nat. Geosci. 12, 333–338 (2019).

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