“Where no one has looked before”: NASA’s probe will look for water on the Moon

Lunar Flashlight is a spacecraft that will shine infrared light on some permanently shadowed parts of the Moon in search of water. NASA plans to launch it next month.

The briefcase-sized satellite will scan the Moon’s south pole, where there may be reservoirs of icy water located inside permanently shadowed regions.

Lunar Flashlight can detect these reservoirs, which are usually at the bottom of craters, using near-infrared lasers using a four-laser instrument called a “reflectometer.”

Infrared waves are absorbed by water, so any evidence of the substance will be reflected back to the satellite by lunar rocks and soil. This method could allow NASA to not only find reservoirs, but potentially find out how large they are, as more absorption can indicate more water.

“This launch will put the satellite on a trajectory that will take about three months to reach its science orbit,” John Baker, Lunar Flashlight mission project manager, said, quoted in a press release by NASA. “Then Lunar Flashlight will try to find water ice on the surface of the Moon in places that nobody else has been able to look at.”

The Lunar Flashlight will use a new type of fuel developed by the Air Force Research Laboratory called “monofuel” because it does not require a separate oxidizer to burn, instead relying on a catalyst. NASA says this monopropellant is safer to transport than something like hydrazine, which is more widely used.

Because fuel will be limited by the small size of the satellite, Lunar Flashlight will use a more economical, nearly rectilinear halo orbit, similar to the future Lunar Gateway space station. Mission navigators will guide Lunar Flashlight past the Moon, where the gravity of Earth and the Sun will pull it back, allowing the satellite to enter a wide oval orbit. It will be only the second NASA mission to use this type of orbit, after CAPSTONE. At its closest point to the Moon, the Lunar Flashlight will fly 15 kilometers above its surface.

Finding icy water that can be turned into drinking water, fuel, or even breathable oxygen is an important first step in creating long-term settlements for astronauts on the moon. The Lunar Flashlight is scheduled to launch aboard a SpaceX Falcon 9 rocket in mid-November and is part of NASA’s ongoing effort to learn more about the Moon before the Artemis program becomes a full-fledged effort to return humans to our natural satellite.