NASA’s Artemis II mission—a slingshot around the moon earlier this year that sent four astronauts to lunar space for the first time in more than half a century—was an unequivocal success. The voyage was chiefly a technological stepping stone for future crewed forays to the lunar surface, which should culminate with the founding of a small base near the moon’s south pole. But it was also a chance to carry out novel observations of the lunar farside, a largely mysterious realm that has been rarely glimpsed by human eyes.
Although Artemis II’s Orion spacecraft carried minimal science payloads, its astronauts were equipped with digital cameras (and iPhones)—and between April 1 and 10, they captured 814 gigabytes of lunar science data. At a press conference yesterday NASA presented its preliminary findings, which touch on everything from the moon’s surprisingly colorful craters to a series of curious flashes that the astronauts spied in lunar shadows. The release also includes more than eight hours of audio from the crew, videos of their nail-biting return to Earth, hand-annotated images, and much more—all available in a vast online repository.
Besides being breathtaking, the mission’s high-resolution imagery helps address more pragmatic queries: Which landing sites might be best for upcoming missions, and how safe would an outpost somewhere on the lunar farside be? “These findings are going to help shape future Artemis mission architectures,” said Marie Henderson, Artemis II’s deputy lunar science lead, during the press conference.
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The crew’s sojourn around the moon may have been brief—just under seven hours—but they still surveyed a large swath of the farside, some of which was cloaked in total darkness. Arguably, the mission’s most important discovery emerged from those shadowy regions: five flashes of light, each in a different location on the lunar farside.
These were meteorite impacts. That isn’t inherently surprising: the airless moon gets bombarded by cosmic debris all the time. Sometimes these impactors—either asteroids or cometary fragments—are relatively big: in the spring of 2024, for example, a 15-meter object slammed into the moon with the force of an atomic bomb, cutting out a 222-meter-long pit.
Mostly, though, the moon is pelted by meteoroids the size of bullets or footballs. Each could, with a direct strike, kill an astronaut or trash a fancy new moon rover, so it’s good to know how often these small-but-lethal space rocks rain down on the lunar surface.
That’s why understanding what the Artemis II crew saw on the farside “matters for the future of human exploration,” said Jen Heldmann, a member of Artemis II’s lunar science team and deputy project scientist for Artemis IV, at the press event. Based on the brightness and brevity of the five flashes, scientists think each meteoroid was around 8.5 grams in mass—about as much as two dice. That may seem harmless, but they were moving at tens of kilometers per second, so these impactors are akin to space bullets.
The Artemis II crew flew outside any major annual meteoroid streams, meaning the five impacts they saw in just under an hour likely represent the typical background rate of small meteorite impacts on the lunar surface. With that in mind, NASA gauged the likelihood for a similar space bullet striking a future moon base: about a one-in-10,000 chance per decade. “We’re probably safe going forward,” Heldmann said.
The astronauts were also on the lookout for swarms of lunar dust. This jagged microscopic debris, easily dispersed by meteorite impacts and rocket exhaust, is corrosive, abrasive and adhesive. It makes quick work of wires, space suits and other hardware, chewing through them like space piranhas. Everyone hates it; it’s a major long-term hazard.
During the Apollo moon missions of the 1960s and 1970s, astronauts occasionally reported seeing hazes of sunlight-lofted dust drifting over parts of the lunar surface. But the Artemis II crew didn’t see any, suggesting that this strange phenomenon may be a transient problem rather than a persistent one.
The Artemis II images also revealed the subtle colors of lunar geology, showing that the moon’s seemingly monochrome surface is actually dappled with greens, yellows, grays and browns. Each of these hues, NASA’s analysis confirms, correspond to different types of ancient volcanism, from glasslike oozes to rubbly pyroclastic flow deposits. NASA also hoped that the crew could spy tectonic landforms during their flyby—things like faults, including those that could rupture and create prolonged, and potentially structure-toppling, moonquakes.
At one point, the crew caught a surreal series of arching crevasses in Oceanus Procellarum (the “Ocean of Storms,” a huge basin filled with primeval lava). These were wrinkle ridges, thought to form when the weight of the erupted lava squashes down on the moon’s crust, causing it to snap and contract. “The fact that they were able to see that from orbit was pretty phenomenal,” says Debra Needham, a member of the Artemis II science operations team.
Despite the fanfare of an official press conference, in truth, nothing in NASA’s report is especially revelatory. If anything, it serves as a reminder that unlocking the moon’s secrets—its alien geology, its hazardous landscapes and any scientific or economic treasures it may hold—relies getting a closer, surface-level look via more crewed and robotic investigations. In late September NASA also announced three new science payloads for near-future landings, all building on Artemis II’s success and adding to the case for an eventual moon base. One will monitor micrometeor impacts and other environmental threats at the lunar south pole, a second will search for hollow “lava tubes” that could be sites for underground habitats and a third will study how water ice might accumulate in and change the stability of lunar soil.
The report’s emphasis on future exploration was also tempered by an intentional callback to the past. NASA officials noted that their report’s release date, October 7, has significance in spaceflight history: on this day, back in 1959, the Soviet Union’s Luna 3 space probe beamed back the first-ever images of the moon’s farside, showing it to be a heavily scarred, crater-filled wasteland.
Luna 3’s images were eye-opening but still blandly colorless and fuzzy—especially compared with the kaleidoscopic, panchromatic views from Artemis II’s lunar pirouette. The alluring vistas the astronauts captured on digital cameras and iPhones helped ensure that “the entire world was united around our mission, and our crew,” says Kelsey Young, Artemis II’s lunar science lead. If NASA sticks to its plan and voyages to the moon become commonplace, then extraordinary images like these will quickly become glorious in their ordinariness.
