What was that? Snowflakes in space – John Glenn and Scott Carpenter, 1962

4 min read

In orbit around the Earth, the first American astronauts found themselves in a cloud of tiny, brilliant particles, as if fireflies or snowflakes had surrounded the capsule. This year, Scott Carpenter's audio recording about it was included in the U.S. government's UFO files release. We looked into it and found that the mystery was solved by Carpenter himself, on the same flight. Our verdict: identified.

The audio that ended up in the UFO files

In May 2026, the United States government released another batch of its files on unidentified aerial phenomena. Most of the material comes from the Department of Defense, but seven files came from NASA: old audio recordings in which astronauts talk about strange sights.

One of them features Scott Carpenter's voice from 1962. He talks about tiny particles drifting in and out of his field of view, and says that to him they look exactly like snowflakes. In a UFO files release, this sounds exciting. However, no explanation is attached to the recording, even though the story has an important continuation.

1. John Glenn, February 20, 1962

The story began three months earlier. In the Friendship 7 capsule, John Glenn became the first American to orbit the Earth. At his first sunrise, he radioed down the following:

"I'm in a big mass of thousands of tiny particles surrounding me, which are brilliantly lit up, as if they were giving off light."

According to Glenn, they were like a firefly on a pitch-dark night. They moved very slowly; some of them resembled curling snowflakes, others star-shaped ones.

What even Glenn didn't know

Glenn himself first thought of ice and frost, but he did not know where they could be coming from. The particles disappeared over the Pacific Ocean, then returned at the next sunrise. The phenomenon became known as "Glenn's fireflies," and ground control was also concerned about whether the capsule's heat shield was coming off in pieces.

2. Scott Carpenter, May 24, 1962

Carpenter flew in the Aurora 7 capsule, and he too ran into the particle cloud. He said over the radio:

"To me they look exactly like snowflakes."

This is the moment preserved in the audio recording released in 2026. Ground control asked whether he had tried to turn around to get a better look at them. Carpenter said no, and again only said that they definitely looked like snowflakes.

The knocking

The solution came about by accident. During the last sunrise, Carpenter bumped his hand against the capsule wall, and a new cloud of particles immediately appeared in front of the window. He then knocked on the wall deliberately, and with every blow a new swarm rose up.

From this it was clear that the particles were not coming from outside, but were coming off the capsule itself. Carpenter named them "frostflies." Decades later, he recalled that he had been especially pleased to have solved the mystery of John Glenn's fireflies.

3. How did a solved case become a UFO file?

Contemporary summaries simply closed the matter this way: one less space mystery. Yet the fireflies lived on. The film The Right Stuff (1983) portrayed them in an almost mystical scene, and now the audio recording has turned up in a UFO files release.

This does not mean that NASA considers it a mystery. Upon release, the government itself stated that the records are not to be regarded as analysis, investigative conclusions or findings of fact. A long-solved phenomenon can thus end up in the same release as genuinely unresolved cases, and from the outside it is hard to tell the two apart.

The most common objections

"If the government released it as a UFO file, then it's a mystery." The release is raw material, not a verdict. The government explicitly indicated that no conclusions should be drawn from the records.
"They glowed, so they had their own light." No: sunlight reflected off them against the black of space, just as a speck of dust lights up in a sunbeam.
"Glenn didn't knock, and he still saw them." The frost came off the warming capsule even without knocking. Carpenter's blows only released even more of it, and that proved the source.

Images and videos

Transcript of Carpenter's radio communications, 1962 – searchable transcript of the Mercury flights on Spacelog
On the audio recordings in the 2026 files release – NBC News report

The sober take

The fireflies were tiny ice and frost crystals coming off the outer surface of the Mercury capsule. Three factors explain them:

The source is the capsule itself. Vapor escaping from the capsule and from the astronaut's body condensed on the cold outer surface and froze into a thin layer of frost in the Earth's shadow.
Sunrise sets it off. When the capsule emerged from the shadow into sunlight, the frost layer warmed up and came off in tiny flakes. That is why the particles always appeared at sunrise.
Sunlight makes them visible. The flakes did not emit light: against the black of space, the sunlight falling on them reflected off them.

Why did they move so slowly? The flakes came off the capsule and continued orbiting at almost the same speed as it, so relative to it they drifted only slowly.

Why snowflakes, of all things? Because that is truly what they were, or at least something very similar: tiny ice crystals glittering in the sunlight. Carpenter's comparison was more accurate than he thought. The decisive evidence came from the knocking: if a blow to the wall sets off a new cloud of particles, the source can be nothing other than the capsule itself.