The Moon's Poles: Lunar Incognita?

The Lunar Poles are of topical interest as they represent the likely location of the next lunar outpost. A primary reason for this selection is that they experience illumination conditions that are unique in our solar system. The near-perpendicular orientation between the lunar spin axis and the ecliptic plane causes the possibility of illumination extremes, either permanent shadow or constant sunlight.

Initial details on the polar illumination conditions were derived using Clementine image data. It has been shown that floors of impact craters up to 12° from each pole contain permanent shadow. These regions are likely cold enough to support the existence of ice deposits. Additionally it is feasible that topographic highs near both poles could experience near-constant sunlight. Analysis of Clementine UVVIS data revealed that nowhere near the south pole was constantly illuminated during a day in winter. Places were identified that were illuminated for an entire lunar day in summer, however the Clementine data did not contain sufficient temporal information to be able to determine if these places are lit throughout the whole year.

Further information has come from SMART-1's AMIE data that have shown that areas near the south pole exist that are lit for an entire day in summer. Additionally AMIE data has provided more details on the geology and age of the environs of Shackleton crater.

There are still several unknowns associated with the polar regions:- is there ice in the permanently shadowed craters? Exactly how cold are these regions? What is the morphology within the craters? Do areas of constant illumination exist at either pole? Hopefully all of these questions will be answered by the fleet of spacecraft either currently at, or soon to launch to the Moon.