HOUSTON — “I just saw a flash! 100%,” Reid Wiseman said inside Orion during the lunar eclipse. About ten minutes later he saw another, and this time Jeremy Hansen had seen it too, a pinpoint of light, “just like a bloop.”
The exchange is in NASA‘s Artemis II Preliminary Lunar Science Report, which counts five distinct impact flashes reported by the crew while the Sun was behind the Moon. Several were seen by more than one astronaut at once. The crew told scientists afterward that they may have seen more, but left any ambiguous flash off the annotated image they sent down.
The detail matters. All five were on the unlit part of the Moon, none were seen in earthshine or sunlight, and NASA’s science team called them likely the faintest ever observed by human eyes, suggesting impactors only several centimeters across. Apollo astronauts recorded flashes from orbit on at least three occasions, one on Apollo 16 and two on Apollo 17, and Earth-based telescopes have logged 443.
NASA released the report on October 7 with the full dataset: more than 800 gigabytes, including over 11,000 full-resolution images and video, and 8.5 hours of audio of the Artemis II crew describing the surface.
Instruments did not back them up. NASA’s Meteoroid Environment Office reviewed Orion exterior-camera video of about two minutes during the eclipse, recorded at 30 frames a second, and found no flashes, though the clip covered a short stretch. Follow-up with the Lunar Reconnaissance Orbiter is probably out, the report says, because craters from such small impacts would be too small for its camera to resolve and the crew’s location information is too rough to aim it.
So the five rest on witnesses. The mission also flew at a low-flux time of year, outside the major annual meteor streams, so the report treats the sightings as a lower bound on the rate of impacts. It uses them to plan future observing, including a possible dedicated automatic flash-detection camera. TEH has covered the next mission, Artemis III, which will stay in Earth orbit.
The crew’s own count is five. By their account it may be higher, and nothing recorded the difference.
