Moon map: NASA just compiled a map of lunar water

A team of scientists used data from NASA's now-retired Stratospheric Observatory for Infrared Astronomy (SOFIA) to compile the first detailed map of water distribution on the moon.

Their new study, published in The Planetary Science Journal, provides new insight into the movement of water across the moon's surface. It provides important data for NASA's upcoming Artemis moon missions, which will send astronauts to explore the lunar south pole.

Mapping the moon's water

NASA's SOFIA telescope was retired in late 2022, mainly due to budget issues. The telescope was mounted aboard an adapted Boeing 747 that would fly to an altitude of up to 42,000 ft (12,800 m). This took it above roughly 99.9 percent of the water vapor on Earth, which would otherwise block much of the infrared light captured by the observatory.

Now, the new map compiled using SOFIA data covers roughly one-quarter of the Earth-facing side of the lunar surface below 60 degrees latitude, including the moon's south pole.

"When looking at the water data, we can actually see crater rims, we see the individual mountains, and we can even see differences between the day and night sides of the mountains, thanks to the higher concentration of water in these places," Bill Reach, director of the SOFIA Science Center at NASA’s Ames Research Center in California’s Silicon Valley and lead author on the study, explained in a NASA blog post.

Using the new data, the scientists were able to determine how water is linked to specific surface features on the moon as well as how it favors cold areas and stays away from sunlight.

Preparing for future crewed moon missions

In 2024, NASA aims to send its first crewed Artemis mission, Artemis II, around the moon and back. In the same year, the space agency will also send its Volatiles Investigating Polar Exploration Rover (VIPER) rover to the moon's surface to conduct resource mapping. It will utilize the SOFIA map as a guide.

That will then pave the way for Artemis III and following astronaut missions to the lunar surface. Ultimately, NASA aims to establish a permanent colony on the moon that will serve as a stepping stone for future human exploration of Mars. The new SOFIA map will serve a crucial role by helping determine areas future missions should focus on for water, which can also be converted into breathing oxygen and rocket propellant.

Study abstract:

The amount and distribution of water on the lunar surface are related to the input and production of water by solar wind and meteoroid bombardment, balanced by photodestruction and mobility across the surface. Using the Stratospheric Observatory for Infrared Astronomy (SOFIA), we imaged the 6.1 μm feature that uniquely traces molecular water, covering 1/4 of the lunar nearside surface south of −60° latitude with 5 km resolution on 2022 February 17 UTC. The water feature strength varies significantly across the region, being drier at +28° longitude to more wet (170 ppm) at −7° longitude, and also decreasing toward the pole. Significant local enhancements are found, associated with south-facing, high-altitude topographic features. This includes relatively high H2O concentrations in a "wet ridge" just north of the Curtius crater; the south-facing, northern, inner rims of the most prominent craters; the south face of the central peak of the Moretus crater; and permanently shadowed polar regions.