An upper limit for ice in Shackleton crater as revealed by LRO Mini-RF orbital radar

B. J. Thomson, D. B J Bussey, C. D. Neish, J. T S Cahill, Essam Heggy, R. L. Kirk, G. W. Patterson, R. K. Raney, P. D. Spudis, T. W. Thompson, E. A. Ustinov

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Although diverse measurements have indicated H+, OH-, or H2O species in the lunar polar regions, pinpointing its location, form, and abundance in specific reservoirs has proven elusive. Here we report on the first orbital radar measurements of Shackleton crater near the lunar south pole. Mini-RF observations indicate a patchy, heterogeneous enhancement in CPR (circular polarization ratio) on the crater walls whose strength decreases with depth toward the crater floor, a result that is most consistent with a roughness effect due to less mature regolith present on the crater wall slopes. However, the results do not rule out a modest ice contribution, and an upper limit of ̃5- 10 wt% H2O ice (up to 30 vol.%) present in the uppermost meter of regolith is also consistent with the observations.

Original languageEnglish
Article numberL14201
JournalGeophysical Research Letters
Issue number14
Publication statusPublished - 28 Jul 2012
Externally publishedYes


ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Geophysics

Cite this

Thomson, B. J., Bussey, D. B. J., Neish, C. D., Cahill, J. T. S., Heggy, E., Kirk, R. L., Patterson, G. W., Raney, R. K., Spudis, P. D., Thompson, T. W., & Ustinov, E. A. (2012). An upper limit for ice in Shackleton crater as revealed by LRO Mini-RF orbital radar. Geophysical Research Letters, 39(14), [L14201].