NASA scientists have confirmed that water ice is present on the moon's north and south poles.
The discovery is significant because it raises hopes for potential returns to the moon, including creating a permanent base there.
"With enough ice sitting at the surface - within the top few millimetres - water would possibly be accessible as a resource for future expeditions to explore and even stay on the moon," NASA said.
Using the space agency's Moon Mineralogy Mapper (M3), researchers from the Ames Research Center in California were able to determine that ice is present in moon craters devoid of sunlight.
"Most of the newfound water ice lies in the shadows of craters near the poles, where the warmest temperatures never reach above minus 250 degrees Fahrenheit [156C]," a statement by NASA's Jet Propulsion Laboratory said.
"Because of the very small tilt of the moon's rotation axis, sunlight never reaches these regions."
The Chandrayaan-1 spacecraft, which was launched by the Indian Space Research Organization in 2008, confirmed the craters contain ice.
"It collected data that not only picked up the reflective properties we'd expect from ice, but was able to directly measure the distinctive way its molecules absorb infrared light, so it can differentiate between liquid water or vapor and solid ice," NASA said.
President Donald Trump announced last year that the US is planning to initiate new moon missions.
The last time humans walked on the lunar surface was in 1972 when astronauts Eugene Cernan and Harrison Schmitt took part in the Apollo 17 mission.
The announcement comes after several important discoveries were made on Mars.
Last month, scientists from the Italian space agency discovered a large underground lake on Mars, which could significantly increase the probability of life on the Red Planet.
It was the first time pure liquid water was found on Earth's closest neighbour.
In June, NASA's unmanned Curiosity rover detected a "repeatable identifiable methane cycle", which could be a sign of active biological processes.
