There is water on the moon’s surface, and ice may be widespread in its many shadows, according to a pair of studies published Monday in the journal Nature Astronomy. The research confirms long-standing theories about the existence of lunar water that could someday enable astronauts to live there for extended periods.

One scientific team found the telltale sign of water molecules, perhaps bound up in glass, in a sunlit region. Another group estimated the widespread prevalence of tiny shadowed pockmarks on the lunar landscape, possible shelter for water ice over an area of 15,000 square miles.

Moon water has been eyed as a potential resource by NASA, which created a program named Artemis in 2019 to send American astronauts back to the moon this decade. Launching water to space costs thousands of dollars per gallon. Future explorers may be able to use lunar water not only to quench their own thirst but to refuel their rockets.

The conception of a bone-dry moon persisted widely until relatively recently. Astronomers in the 1800s believed the moon must be waterless because they could not see lakes or clouds through their telescopes. That notion was reinforced by the powdery lunar surface the Apollo astronauts saw and felt through the soles of their boots a half century ago.

A Soviet probe may have collected moon water, but that research, published in a Soviet journal in 1978, went largely ignored.

But in the 2000s, a picture of a water-tinged moon began to emerge. Careful studies of moon samples and spacecraft observations helped overturn the notion of a total lunar desert. In 2018, scientists found ice deposits at the moon’s poles, which the Apollo astronauts did not visit. The lunar south pole in particular is believed to have reservoirs of potentially useful water in either ice or molecular form — though certainly not liquid.