1. EPITHERMAL FLUX DEPRESION AND PSR IN SHOEMAKER CRATER V.V.Shevchenko 1, I.G.Mitrofanov 2, E.A.Kozlova 1, A.A. Shangaraev 1, and the LEND Science Team 1 Sternberg State Astronomical Institute, Moscow University 2 Space Research Institute, RAS THE SECOND MOSCOW SOLAR SYSTEM SYMPOSIUM MOONS OF PLANETS MOSCOW 2011 IKI RAS

2. Unique capability of LEND to measure epithermal neutron albedo with high spatial resolution allow to create maps with resolution up to 10 km for circumpolar areas (Mitrofanov et al., 2011).

6. Well-seen NSR with area about 1500 km 2 was detected within crater Shoemaker. Its boundary coincides very well with the contour of PSR in the bottom of this crater. In this case the surface of NSR is permanently cold, and there are perfect conditions for permanent storage of frozen water in the regolith

7. , TEMHERATURE MODEL OF CRATER SHOEMAKER Temperature, K

8. T < 70 K

11. At speed of formation of a layer of regolith equal 1 cm (Killen et al., 1997) or 15 cm (Morris, 1978) for 50 million years for formation of a shielding layer by thickness of 0,2 – 0,5 m it is necessary on the average 1 billion years. Using similar Clementine data for other lunar regions of mare and highland types, we obtained a scale of conformity between OMAT, spectropolarimetric maturity indexes and exposure age of surface soil (Shevchenko et al., 2003).

12. The maturity index values ranging from 0,15 to 0,20 correspond to exposure age from 0,2 to 0.4 billion years.

13. SUMMARY: It’s possible that a shielding layer in crater Shoemaker has a thickness up to 0.5 – 1.0 meter shielding layer frozen water layer?

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