In this laser elevation map of Shackleton crater, false colors indicate height, with blue lowest and red highest. Credit: NASA/Zuber, M.T. et al., Nature, 2012
The Moon is taking on an icy look thanks to NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft.
Using a laser altimeter on the LRO, a research team essentially has illuminated the crater’s interior of Shackleton crater.
Scientists from MIT, Brown University, NASA’s Goddard Space Flight Center and other institutions have mapped Shackleton crater with unprecedented detail. That crater resides at the Moon’s south pole.
The research team reported this week of finding possible evidence for small amounts of ice on the crater’s floor.
Indeed, if humans are ever to inhabit the Moon, the lunar poles may well be the location of choice.
Why?
The poles contain regions of near-permanent sunlight, needed for power, and regions of near-permanent darkness containing ice – both of which would be essential resources for any lunar colony.
Transforming ice into oxygen and propellant would be a bonus for future explorers that are establishing permanent habitats on the Moon.
Shackleton crater — named after the Antarctic explorer Ernest Shackleton — is more than 12 miles wide and two miles deep — about as deep as Earth’s oceans.
Strong evidence for ice
Using laser light transmitted from LRO, scientists measured the crater’s albedo, or natural reflectance. The crater’s floor was found to be brighter than that of other nearby craters — an observation consistent with the presence of ice.
“The crater’s interior is extremely rugged,” said Maria Zuber, the team’s lead investigator from the Massachusetts Institute of Technology in Cambridge in Mass. “It would not be easy to crawl around in there,” she noted in a press statement.
Zuber and her colleagues have produced an ultra-high-resolution map that provides strong evidence for ice on both the crater’s floor and walls.
The brightness measurements have baffled researchers.
Scientists had thought that if ice were anywhere in a crater, it would be on the floor, where no direct sunlight penetrates. The upper walls of Shackleton crater are occasionally illuminated, which could evaporate any ice that accumulates.
A theory offered by the team to explain the puzzle is that “moonquakes”– seismic shaking brought on by meteorite impacts or gravitational tides from Earth — may have caused Shackleton’s walls to slough off older, darker soil, revealing newer, brighter soil underneath.
The findings have been published in the scientific journal Nature.
The research was supported by the Lunar Reconnaissance Orbiter Mission under the auspices of NASA’s Exploration Systems Mission Directorate and Science Mission Directorate.
For more information on LRO and the Lunar Orbiter Laser Altimeter, go to:
By Leonard David