In the not-too-distant future, American astronauts will once again set foot on the moon’s silvery desolation. Instead of brief jaunts around the low-latitude frozen lava seas on the orb’s Earth-facing hemisphere like their Apollo-era forebears, however, the moonwalkers of NASA’s Artemis III mission will be targeting the lunar south pole—a region that holds ancient deposits of water and, just possibly, the future site of a permanent astronaut outpost. The mission will have a crew of four, but two will remain in lunar orbit while the other pair touches down on the southern polar region and scoots briefly across the surface. And as they do so, they will deploy a suite of scientific instruments to forensically examine what will then be the most important parcel of off-world real estate in the solar system.
After considering myriad proposals, NASA has now announced three gadgets chosen to accompany the Artemis III crew members on their voyage: The Lunar Environment Monitoring Station (LEMS) package is a remarkably precise seismometer that is designed to listen out for moonquakes and survey the lunar geological underworld. The Lunar Effects on Agricultural Flora (LEAF) instrument will attempt to grow three crops on the moon and study how they respond to the mercurial, extreme environment. And the Lunar Dielectric Analyzer (LDA) will use the flow of electric currents through the lunar soil to detect the presence of volatiles, most notably water ice.
These three instruments are not guaranteed to find their way to the lunar south pole. Additional developmental work is required to ensure each can fulfill its scientific objectives and to quadruple-check that all are compatible with Artemis III’s launch architecture and carefully choreographed surface excursions. But the signal NASA wishes to broadcast with this tentative selection of doodads is already loud and clear: more than a half-century after the flash and fade of Apollo, the U.S. is returning to the moon for the long haul.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
“We want Artemis to be sustainable,” says Noah Petro, Artemis III’s project scientist.
Establishing a bona fide moon base requires ascertaining several things: the risk to structures from moonquakes, the possibility of growing plants on the moon and the likelihood of finding water to use there. This trio of instruments will seek answers to those practical queries while conducting basic scientific investigations on the moon’s scarcely explored far side. “We’ve got this great scientific story to tell,” Petro says. And if all three work wonders, “we are going to be setting a precedent that other missions will have to meet.”
Shaking and Quaking
Sophisticated scientific instrumentation is no stranger to the lunar surface, which now hosts a surprisingly diverse array of experiments sent there with ever increasing cadence over the past few years by multiple space agencies and spaceflight companies. But wonky landings and straight-up crashes have produced decidedly mixed results for these ventures, which all relied on automated robotic deployments.
Using astronauts to unpack and set up experimental apparatuses is far more expensive yet also has a far superior track record of success. “The added advantage of having people there is that you get a little bit more flexibility,” says Ben Fernando, a seismologist at Johns Hopkins University. “People can debug things.” And of course, you can ensure that the experiments are as close to their optimal locations and configurations as humanly possible—something of paramount importance to LEMS, which is one of the most precise and sensitive seismometers ever developed.
LEMS is actually a pair of seismometers, each of which will be used to detect two different types of seismic rumbles. One will be inserted into a borehole, while the other will be put into an excavated ditch. Because astronauts will place them, both are nigh guaranteed to be perfectly coupled with the ground and shielded from an excess of environmental surface noise.
It may sound absurd that digging holes is a key reason astronauts are required to deploy these seismometers. Robots have had a famously difficult time drilling into the surprisingly resistant soils of both the moon and Mars, however. Although astronauts have found this challenging, too—the Apollo moonwalkers struggled with some of their deployments—they can troubleshoot in real time in ways no robot can (yet). “Yes, it takes enormous amounts of money to put astronauts on the moon. But if they’re there anyway, how hard is it for them to dig a trench?” says Paul Byrne, a planetary scientist at Washington University in St. Louis and a member of the LEMS team.
Solar-powered by day and battery-powered by night, LEMS will gradually build up a richly detailed seismic picture of the understudied south pole. The experiment will beam its hard-won readings back to Earth once a month to add to preexisting data from Apollo-era seismometers at sites on the moon’s near side. “If it is used as planned, this thing will last for two years on the lunar surface,” Byrne says. That should be more than enough time to fill in gaps in information about the frequency of south polar moonquakes and the bulk structure of the lunar subsurface there—crucial data points for reasons of not just science but also safety.
“If you want to establish a permanent settlement on the lunar south pole, you better understand the seismic state of that environment in the long term,” says Mehdi Benna, a planetary scientist at the University of Maryland, Baltimore County, and LEMS’s team leader.
“I’m delighted they selected this,” says Thomas Watters, a planetary scientist at the National Air and Space Museum in Washington, D.C. Apollo-era seismometers revealed not only that the moon has sporadic temblors but that some of the most intense happened around the lunar south pole. And although Earth’s quakes can be far more powerful, “these things can last for hours on the moon, not just minutes,” Watters says. “You’ve got to be prepared for that.”
Quakes aren’t the only things LEMS will detect. Car-sized space rocks burn up harmlessly in Earth’s atmosphere, whereas they plow unimpeded into the lunar surface, making them a hazard. On the moon “impacts can happen anywhere,” Fernando says—and LEMS will be able to assess the impact rate around the lunar south pole.
A Farm on the Moon
The lunar south pole’s allure for human exploration comes from its nearly constant access to solar power—and also from the water ice thought to lurk in abundance within deeply shadowed craters and in the shallow subsurface. Melted and purified, that ice could be used as potable water; split into constituent hydrogen and oxygen, it could provide rocket fuel and breathable air. Yet first, scientists need to ascertain just how much H2O actually exists there to use—something that the LDA instrument will address by assessing how electric fields subtly convulse when propagating through the lunar soil.
Picking an ideal deployment spot—one that experiences both day and night, for example—could be crucial for LDA’s studies. And the requisite mobility and precision are “very, very difficult for a robotic mission but probably very easy for trained astronauts,” says Hideaki Miyamoto, a planetary scientist the University of Tokyo and LDA’s team leader. Robots will still assist the effort, however: LDA’s siting will be indirectly supported by NASA’s Volatiles Investigating Polar Exploration Rover, or VIPER, which will sniff out water molecules in the south polar region after it launches later this year.
But before any lunar water is used to irrigate crops for hungry astronauts, NASA’s mission planners want to ensure edible plants can even grow on the moon in the first place. That’s LEAF’s task. This instrument is essentially a space-age terrarium, featuring an enclosed growth chamber to nourish three crops—Wolffia (known as duckweed), Brassica rapa (related to turnip and bok choy plants) and Arabidopsis thaliana (thale-cress)—and protect them from the harsh lunar environment.
All three well-studied model plants have been flown in space before. By taking root on the moon, however, they will enter scarcely charted agricultural realms. Once LEAF has been deployed, its seeds will be pampered with water, nutrients and light in a clement atmosphere, “much like an indoor farm does on Earth,” says LEAF’s team leader Christine Escobar, an ecologist and vice president of Space Lab Technologies in Boulder, Colo. Cameras and various sensors will monitor their growth. Some of the quickly germinating plants will be harvested for further study by the Artemis III team, while others will continue to grow until the long, cold darkness of lunar night falls.
LEAF is the instrument that is most explicitly tied to the creation of a long-term presence on the lunar south pole. “Human nutrition and life support—carbon dioxide removal, oxygen production and water purification—provided by space agriculture will enable long-duration human exploration of the moon and beyond,” Escobar says.
Even if LEAF’s tranquil terrarium makes a giant leap in otherworldly botany, it will be but a small step toward true lunar farming, which faces myriad challenges such as lower gravity, higher radiation levels and a dearth of high-quality soil. “Lunar regolith will likely be used for plant growth facilities in established lunar bases,” says Anna-Lisa Paul, a horticultural scientist at the University of Florida. She recently attempted to grow thale-cress in lunar soil obtained by the Apollo missions. Although the experiment was successful, the plants hated it; they were slow to develop and exhibited signs of stress. You must start somewhere, however, and what LEAF will tell botanists will be invaluable. “Based on what is discovered, the next step could be to help plants with specific difficulties either by engineering them to better enable them to physiologically adapt or [by] choosing crop species that are naturally better suited to dealing with that particular stress response,” Paul says.
Altogether, NASA’s choice of these instruments further reinforces how seriously the agency is pursuing its intentions to return humans to the moon—this time, to linger and perhaps even stay. After LEMS, LDA and LEAF have done their work, Fernando says, it’ll be harder to argue against the moon as “somewhere you could, in theory, have people live for an extended period of time.”
The Artemis program may have been subject to various controversies, technical challenges and budgetary overspills—but announcements like this one make the long-awaited lunar return, and NASA’s ambitions to remain there, seem that much more tangible. “We’re going to see humans on the moon. And that’s going to start changing how we view the whole enterprise,” Byrne says. “This is not going to be planting the flag and going home.”