"Water ice in amounts of up to 20 percent is a viable possibility," study lead author Maria Zuber, a geophysicist at the Massachusetts Institute of Technology, told SPACE.com.
Don't get your hopes up, though. The amount of ice in Shackleton Crater "can also be much less, conceivably as little as zero," Zuber cautioned.
This uncertainty is due in part to what the researchers saw in the rest of the crater. Bizarrely, while the crater's floor was relatively bright, Zuber and her colleagues observed that its walls were even more reflective.
Scientists had thought that if highly reflective ice were anywhere in a crater, it would be on the floor, which live in nearly permanent darkness. In comparison, the walls of Shackleton Crater occasionally see daylight, which should evaporate any ice that accumulates.