The thought of an astronaut strapped inside a capsule a quarter of a million miles from home, leaning toward the window and catching a flicker of light on the grey skin of the moon, is subtly exciting. Not a camera. No instrument. Just someone observing. That is basically what happened in early April when the four crew members of Artemis 2 slipped behind the far side of the moon and started reporting what they saw: brief, unrepeatable flashes, each of which was a tiny meteoroid vaporizing against the regolith to end its arduous journey.
As the first crewed lunar orbit since Apollo 17 departed in 1972, the mission itself had already cemented its place in history. However, this seemingly insignificant observational task might end up being one of its most valuable contributions. NASA‘s Artemis lunar science lead, Kelsey Young, told Space.com that the observations were made with the unaided eye and noted how stubbornly hard it is to capture these flashes on camera. That sentence contains a subtle argument that some types of science still require a skilled human looking out a window.
That same evening, a parallel effort was taking place down on Earth. For the Impact Flash citizen science project, volunteers from all over the world pointed small telescopes at the moon and captured footage. It’s likely that the majority of them did not experience the same strikes as the astronauts. That is practically impossible with just geometry. However, the overlap—the infrequent instances in which a crew in orbit and an observer on Earth see the same speck of light at the same moment—is what makes it valuable.
This type of paired observation has long been advocated by the project’s lead, planetary scientist Benjamin Fernando, who is currently employed at Los Alamos National Laboratory. He and his colleagues described how coordinated viewing, both from the ground and from lunar orbit, yields information that neither approach can provide on its own in a preprint paper published earlier this year. timing, location, approach angle, and impactor size. You can only construct this type of dataset gradually, one flash at a time.
The astronauts have fallen to the ground. Until Artemis 3, at least, their role is done. However, there are still volunteers. One of them, a man by the name of Joerg Tomczak, submitted a picture of his telescope on a tripod under warm orange porch lights, along with a tiny inset that showed a single bright dot circled in orange that might be an actual impact candidate. It’s an oddly personal picture. Backyard equipment, ordinary night, possible cosmic event.
The project’s future direction is what makes it worthwhile to follow. Fernando has revealed plans to place seismometers—devices that will record the moon’s subtle tremors, or “moonquakes”—on the moon’s surface. When you connect those readings to a known flash, you can map what’s under the dust and see inside the moon. It is patient science, the kind that gradually accumulates thousands of tiny contributions.
Observing this develop gives me the impression that the way lunar exploration is conducted has changed. The Italian researchers maintaining the data pipeline, the experts in the capsule, and the amateurs in their gardens were all combined into one endeavor. As it happens, the moon continues to reveal itself. Additionally, more people are observing this time.
