The Surface Morphology of the Partially Shadowed Floors of Three Craters near the Pole of the Moon

On the basis of the photogeologic analysis of images acquired with the ShadowCam and the Narrow Angle Cameras of the Lunar Reconnaissance Orbiter (LROC NAC) as well as with the use of the Lunar Orbiter Laser Altimeter (LOLA) measurement data, we study the surface morphology of near-polar craters Schomberger A, Rozhdestvenskiy K, and Lovelace, the floors of which are only partially shadowed. The Schomberger A crater is located in the south polar region. This crater is the smallest of the three under consideration (its diameter is 31 km) and the youngest (it dates back to the Copernican period). There is almost no regolith on its floor and inner slopes. In the study areas on its floor, small craters exhibit no lobate rims, which is evidently caused by almost complete absence of regolith there. The Rozhdestvenskiy K crater is located in the north polar region. It is medium in size among the three considered (its diameter is 42 km) and medium in age (it dates back to the Eratosthenian period). On the floor of this crater, the regolith is rather thick; and there are small craters with lobate rims there, which is considered a sign of a rather high amount of water ice in the target material. However, the measurements with the Lunar Exploration Neutron Detector (LEND) did not detect any increased content of hydrogen associated with this crater. The Lovelace crater is also located in the north polar region. It is the largest of the three under consideration (its diameter is 54 km) and the oldest (it dates back to the Late Imbrian period). On the floor of this crater, the regolith is quite thick; and craters with lobate rims are observed there, which is considered an indication of a rather high amount of water ice in the target material. However, the LEND measurements did not detect any increased content of hydrogen in this region either.