- Shoemaker (lunar crater)
lunar crater data
latitude=88.1
N_or_S=S
longitude=44.9
E_or_W=E
diameter=50.9 km
depth="Unknown"
colong=342
eponym=Eugene Shoemaker Shoemaker is a lunar crater that is located near the southern pole of the
Moon , within a half crater diameter of Shackleton crater. It lies to the south of Malapert crater, and just to the west of the similar-sized Faustini crater. The rim of Shoemaker is circular and worn, with some small craters along the inner wall. Due to the lack of illumination, thealbedo of the interior floor surface remains unknown.Prior to being given its current name by the IAU, this formation had been informally named Mawson crater (after the
Antarctic explorerDouglas Mawson ). It was officially named Shoemaker in honor of Eugene Shoemaker, thegeologist whose remains were on board theLunar Prospector spacecraft that impacted this crater floor.Cold trap deposits
This crater became of interest to scientists when the Lunar Prospector detected unusually high concentrations of
hydrogen on the floor of this and other nearby craters using aneutron spectrometer . The floor of this crater is kept in permanent shadow from theSun , and thus maintains a temperature below 100kelvin s. Thus the floor forms a cold trap, and any molecules of water that wander into the crater fromcomet ary impacts can deposit on the floor and remain here almost permanently. The instruments on board the Prospector gave a concentration of about 146 ppm of hydrogen, compared to 50 ppm for the average lunar surface.The topography of this crater was subsequently measured using the
Goldstone 70-meter antenna to irradiate it with 3.5 cmradar . Two 34-meter antennas, located 20kilometer s apart, received the echoes, and the results were used to generate a coarsetopographic map .On
July 31 ,1999 , the Prospector was deliberately crashed into the floor of this crater to determine if a plume of water vapor would be detected. The apparent detection of water and the shallow rim of this crater made it a suitable target for this experiment. However the outcome was unsuccessful. Subsequent tests have failed to confirm the presence of water in the crater floor, so the hydrogen found in the crater bottom is likely to prove more difficult to extract than had been originally hoped.References
* cite news
title=Arecibo radar shows no evidence of thick ice at lunar poles, despite data from previous spacecraft probes, researchers say
publisher=Cornell University News
date=November 12, 2003
url=http://www.news.cornell.edu/releases/Nov03/radar.moonpoles.deb.html
accessdate=2007-08-08
*cite news
title=No Water Ice Detected From Lunar Prospector Impact
publisher=Science Daily
date=October 14, 1999
url=http://www.sciencedaily.com/releases/1999/10/991014080522.htm
accessdate=2007-08-08
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