NASA’s ‘flashlight’ will hunt hidden lunar water

NASA is sending a “flashlight” to the moon to hunt for hidden lunar water – and its findings could shape future human exploration of the moon’s surface.

The challenge: NASA suspects that the floors of permanently shadowed craters near the moon’s south pole are covered in a thin layer of water ice, but it doesn’t know exactly how much ice or how accessible it might be – and we would like really like to know.

“If we’re planning to send astronauts out there to dig up the ice and drink it, we need to be sure it exists.”

Barbara Cohen

“While we have a pretty good idea that there is ice inside the moon’s coldest and darkest craters, previous measurements were a bit ambiguous,” said lead researcher Barbara Cohen. from NASA’s Lunar Flashlight mission in 2020.

“Scientifically, that’s fine, but if we’re planning to send astronauts out there to dig up the ice and drink it, we have to be sure it exists,” she continued.

Lunar water: On or after November 22, NASA plans to launch Lunar Flashlight, a briefcase-sized satellite, aboard a SpaceX Falcon 9 rocket. The mission of the satellite is to identify surface ice on the floors of shadowed southern craters of the moon.

To do this, he will use an instrument called a “laser reflectometer” to shine four lasers into the craters and measure the reflections. Water will readily absorb light from lasers, while bare rock will reflect it, so these measurements will help reveal how much lunar water is inside a crater.

NASA Solar Powered Lunar Flashlight. Credit: NASA / JPL-Caltech

“We will for the first time make definitive measurements of surface water ice in permanently shaded regions,” Cohen said.

“We will be able to correlate Lunar Flashlight observations with other lunar missions to understand the extent of this water and whether it could be used as a resource by future explorers,” she continued.

The mission: After launch, the lunar flashlight will be sent far beyond the moon before being pulled by gravity from the sun and Earth. The satellite will then settle into a near-rectilinear halo orbit that sees its distance to the moon extend from 42,000 miles to just 9 miles.

“The reason for this orbit is to be able to get close enough for Lunar Flashlight to shine its lasers and get good return from the surface, but also to have a stable orbit that consumes little fuel,” Cohen said.

The lunar flashlight should be able to pass over the southern craters of the moon 10 times in about 2 months. If enough propellant remains after that, it could make additional orbits before the mission ends with a crash landing on the moon’s surface.

“We will for the first time make definitive measurements of surface water ice in permanently shaded regions.”

Barbara Cohen

First of its kind: In addition to helping NASA measure lunar water in shadowed craters for the first time, Lunar Flashlight will also be the first mission to use a laser reflectometer to hunt water ice.

Additionally, it will be the first interplanetary spacecraft powered by “green” propellant, which NASA says is less toxic, more efficient, and easier to store and transport than hydrazine, a fuel commonly used as satellite propellant. .

“A technology demonstration mission like Lunar Flashlight, which is less expensive and fills a specific gap in our knowledge, can help us better prepare for an extended NASA presence on the moon as well as test key technologies that could be used in future missions,” Lunar Flashlight Project Manager John Baker said in 2020.

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