Artemis II astronauts saw flashes on the Moon while circling it in April 2026. These light bursts happened when small rocky fragments hit the lunar surface at high speeds. Because the Moon lacks an atmosphere, these impacts created visible flashes that the crew recorded during their mission to the Moon.

Nasa's Artemis II astronauts witnessed something extraordinary while flying around the Moon: tiny flashes of light suddenly appearing on its dark surface, nearly 74,000 kilometres away.

The flashes, initially appearing as faint pinpricks of light, were caused by small rocky fragments crashing into the lunar surface at tremendous speeds.

The observations were part of a planned scientific experiment during the Artemis II mission, which flew around the Moon in April 2026.

Lunar scientists had specifically asked the astronauts to watch for impact flashes. However, even the scientists were surprised when the crew reported spotting five extremely faint bursts of light from such a vast distance.

Artemis II update! We just dropped 814GB of observations -- including nearly 1,000 new images and 521 minutes of crew audio -- in our Artemis II Preliminary Lunar Science Report: https://t.co/qHFSHiJUza https://t.co/vnAC5gByT1 -- NASA (@NASA) October 7, 2026

WHAT CAUSED THE FLASHES?

According to Nasa, the flashes were produced by tiny space rocks, likely no larger than a couple of inches across, striking the Moon at thousands of miles per hour.

Despite their small size, the tremendous speed of these fragments released enough energy upon impact to produce brief flashes visible to the human eye.

Unlike Earth, the Moon has virtually no atmosphere to burn up incoming space debris. As a result, even tiny fragments can strike its surface directly.

Scientists initially considered whether the flashes could have been caused by cosmic rays or reflections from the Orion spacecraft. After examining the observations, the science team confirmed them as lunar impact flashes.

WHY COULD ASTRONAUTS SEE THEM?

The sightings occurred while Orion was travelling around the Moon's far side during a planned communications blackout.

At the time, the astronauts were experiencing a nearly hour-long total solar eclipse, with the Moon blocking the Sun and creating exceptionally dark viewing conditions.

Nasa astronauts Reid Wiseman and Victor Glover, along with Canadian astronaut Jeremy Hansen, recorded the locations of the flashes on a tablet.

Apollo astronauts had previously reported similar events, but Nasa scientists believe the Artemis II crew may have witnessed some of the faintest lunar impact flashes ever detected with the unaided eye.

WHY IS THIS DISCOVERY IMPORTANT?

The observations could help scientists better understand how frequently small rocks strike the lunar surface.

That information will become increasingly important as Nasa prepares to establish a sustained human presence on the Moon through its Artemis programme.

Understanding these impacts could help engineers assess risks to future lunar habitats, astronauts, scientific equipment and other infrastructure.

The five tiny flashes have therefore provided scientists with valuable evidence about an invisible hazard awaiting humanity's return to the lunar surface.