Article | Published:

Lunar soil hydration constrained by exospheric water liberated by meteoroid impacts

Nature Geoscience (2019) | Download Citation


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.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

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.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


  1. 1.

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

  2. 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. 3.

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

  4. 4.

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

  5. 5.

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

  6. 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).

  7. 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).

  8. 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).

  9. 9.

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

  10. 10.

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

  11. 11.

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

  12. 12.

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

  13. 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).

  14. 14.

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

  15. 15.

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

  16. 16.

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

  17. 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).

  18. 18.

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

  19. 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).

  20. 20.

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

  21. 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).

  22. 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).

  23. 23.

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

  24. 24.

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

  25. 25.

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

  26. 26.

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

  27. 27.

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

  28. 28.

    International Meteor Organization (accessed 18 January 2018);

  29. 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).

  30. 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).

  31. 31.

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

  32. 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).

  33. 33.

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

  34. 34.

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

  35. 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).

  36. 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).

  37. 37.

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

  38. 38.

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

  39. 39.

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

  40. 40.

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

  41. 41.

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

  42. 42.

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

  43. 43.

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

  44. 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).

  45. 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).

  46. 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).

Download references


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.

Author information


  1. NASA Goddard Space Flight Center, Greenbelt, MD, USA

    • M. Benna
    • , T. J. Stubbs
    •  & P. R. Mahaffy
  2. CSST, University of Maryland, Baltimore County, Baltimore, MD, USA

    • M. Benna
  3. The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA

    • D. M. Hurley
  4. NASA Ames Research Center, Moffett Field, CA, USA

    • R. C. Elphic


  1. Search for M. Benna in:

  2. Search for D. M. Hurley in:

  3. Search for T. J. Stubbs in:

  4. Search for P. R. Mahaffy in:

  5. Search for R. C. Elphic in:


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.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to M. Benna.

Supplementary information

  1. Supplementary Information

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

About this article

Publication history