October 24, 2008

Inside Shackleton

image by JAXA/SELENE (Kaguya). The upper left image shows the normal view of Shackleton; arrows on the large image mark impact craters on the crater rim.

Last March at the Lunar and Planetary Science Conference, Japanese scientists very briefly flashed on the screen an image from their Kaguya spacecraft of the interior of Shackleton crater. This was remarkable because the rim of Shackleton is at the lunar south pole and the crater floor is in perpetual darkness. But Kaguya's Terrain Camera is so sensitive that it could image Shackleton's interior just from the few photons that bounced around the interior from the narrow portion of the rim top that illuminated. Now, in Science magazine the photos have been released and they are absolutely remarkable simply because they clearly show the crater interior. Shackleton has smooth walls, a small flat floor with one big off-center lump and a few small ones. One characteristic of the floor is that it is not bright as it would be if there were water ice on its surface. There still may be ice under a thin veneer of lunar soil, but it is disappointing that the water is not there to be scooped off the surface.

Chuck Wood

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