The moon still holds some mysteries. One of those being whether or not there is any discernible amount of ice on the surface. While we have been to the moon, we have only visited a very small area. The way of knowing without actually going there are hit and miss too. For instance, the Japanese spacecraft Kaguya saw no discernible signs of ice within Shackleton Crater, but NASA’s LCROSS probe analyzed Cabeus Crater near the moon’s south pole and found it measured as much as 5 percent water by mass.

The way they check this is by having a spacecraft illuminate the interior of the crater with infrared laser light, measuring how reflective it was. The scan of The crater’s floor was more reflective than that of other nearby craters, suggesting it had ice. “Water ice in amounts of up to 20 percent is a viable possibility,” study lead author Maria Zuber told SPACE.com. Don’t get your hopes up, though she cautioned. The amount of ice in Shackleton Crater “can also be much less, conceivably as little as zero.”

Zuber noted that the measurements only look at a micron-thick portion of Shackleton Crater’s uppermost layer. “A bigger question is how much water might be buried at depth,” Zuber said, adding that NASA’s GRAIL mission will investigate that possibility. And with that possibility we get the reality of a permanent base on the moon. If there is water in massive amounts, which some suspect there could be. We would have the ability to make rocket fuel and potable water for human settlement.