New information about the interior of the crater Shackleton at the south pole of the Moon sheds some light -- and even more heat -- on the vexing questions remaining about water on the Moon.
Shackleton crater, Moon. Clockwise from top left: topography from laser altimetry, image from SMART-1 mission, lighting map (brighter is longer periods of illumination) from the LRO Camera, Mini-RF CPR image draped over shaded relief map. The crater is about 20 km in diameter.
Though unremarkable in appearance compared to the roughly 4,000 craters on the Moon in its size range, the 20 km diameter crater Shackleton has been the source of relentless scientific controversy for the past 20 years. Shackleton is located at the south pole of the Moon; indeed, its near side rim is the precise location of the geographic pole itself. Its location makes observation by Earth-based telescopes difficult and it was not well photographed by the Lunar Orbiter series (our principal source of lunar images) of the 1960s. That all changed in 1994 with the flight of the joint DoD-NASA mission to the Moon, Clementine.
Clementine carried cameras that globally imaged the Moon in eleven visible and near-infrared wavelengths. In addition, it ...