June 23, 2012
from TheBunsenBurner Website






Officials at NASA say that a crater on the moon hold vast quantities of water in the form of ice, a discovery that could pave the way for future mission to the Earth satellite.

New research shows there may be frozen water inside a massive crater, called the Shackleton crater, say NASA scientists.


Researchers from NASA, MIT, and Brown University say they studied the crater with the help of a laser device, and they note that recorded measurements indicate the presence of ice.


The team of astronomers say the laser lit up the area and allowed them to measure the natural reflectivity inside the crater.

"While the distribution of brightness was not exactly what we had expected, practically every measurement related to ice and other volatile compounds on the moon is surprising, given the cosmically cold temperatures inside its polar craters," said the scientists.

Using NASA's Lunar Reconnaissance Orbiter, the team of astronomers essentially illuminated the crater's interior with infrared laser light, measuring how reflective it was.


In a statement released Thursday, the team noted that the latest data shows that upwards of 20 percent of the crater could be covered in ice.


That said, the measured reflectance could be the result of something else entirely, including mineral deposits located on the floor of the crater.

"The reflectance could be indicative of something else in addition to or other than water ice," said study lead author Maria Zuber, a geophysicist at the Massachusetts Institute of Technology.

For instance, the crater floor might be reflective because it could have had relatively little exposure to solar and cosmic radiation that would have darkened it.

Ms. Zuber noted that the measurements only look at a micron-thick portion of Shackleton Crater's uppermost layer, noting that water may be present at greater depths.

"A bigger question is how much water might be buried at depth," said Ms. Zuber, adding that NASA's GRAIL mission will investigate that possibility.

While the crater could hold ice, it remains unclear whether ice actually exists at the bottom of the crater.


Researchers say the measurements showed this crater's floor is much brighter than the floor of other nearby craters, suggesting there may be ice in it, but they added that they can't be sure.

Scientists estimate there could be as much as 100 gallons of ice inside the two-mile deep crater.

Shackleton crater is very large at 2 miles deep and more than 12 miles wide.


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 (Lack of Exposed Ice Inside Lunar South Pole Shackleton Crater) 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.


Astronomers have studied the crater in recent years, searching for ice deposits in the interior of the crater, which is permanently dark.


While scientists have long posited that ice may exist on the moon, previous orbital and Earth-based observations of lunar craters have yielded conflicting interpretations over whether ice is actually there.

The data comes just months after NASA celebrated the 2012 New Year earlier this year by completing a space administration first, announcing two probes in lunar orbit. For NASA, the announcement was a fulfillment of the space agency's New Year's wish. NASA will use GRAIL-A and GRAIL-B to study Earth's closest neighbor, the moon.

According to the space administration, the GRAIL mission will be,

"the first time any space agency has attempted the complex set of maneuvers required to place two robotic spacecraft into the same precise orbit around a planetary body other than Earth so they can fly in formation."

The probes will spend about two months reshaping and merging their orbits until one spacecraft is following the other in the same low-altitude, near-circular, near-polar orbit, and they begin formation-flying.


The next 82 days will constitute the science phase, during which the spacecraft will map the Moon's gravitational field.