Apollo 10’s “Outer-Space-Type Music” Explained

The Apollo 10 CM "Charlie Brown" photographed from the LM "Snoopy" in lunar orbit (NASA)
The Apollo 10 CM “Charlie Brown” photographed from the LM “Snoopy” in lunar orbit (NASA)

There’s been some buzz recently (no pun intended, Mr. Aldrin) concerning supposed “space music” heard by Apollo 10 astronauts while they were traveling around the far side of the Moon in May of 1969. This is in no small part due to the season three opener of NASA’s Unexplained Files* on the Science Channel, which aired on Feb. 23 and featured a rather dramatic recap of said event.

Long story short, as Apollo 10 passed behind the Moon during day 5 of the mission on May 22, 1969, it was blocked from any communication with the Earth for well over an hour. During that time the astronauts—Tom Stafford, Gene Cernan, and John Young—noted hearing some curious sounds in their headsets, likened to “outer-space-type music.” Hesitant about sharing this unanticipated discovery with Mission Control (astronauts were a notoriously competitive lot and didn’t readily elect to divulge errors in perception) it was kept quiet until they returned to Earth, after which time the recorded in-flight transcripts were filed and stored…and were never digitized for the web until 2012. This led many conspiracy groups to claim that the recordings were kept hidden from the public and are evidence of some sort of alien encounter on the lunar farside… although anyone who listens to the sounds now should be able to tell what they really are. (And no, it’s not alien Muzak.)

The Apollo 10 prime crew at Pad 39B, March 27, 1969 (NASA)
The Apollo 10 prime crew at Pad 39B, March 27, 1969 (NASA)

The below was shared on Facebook by NASA’s Deputy Assoc. Administrator of Communications Bob Jacobs on Feb. 22, 2015:

“While listed as ‘confidential’ in 1969 at the height of the Space Race, Apollo 10 mission transcripts and audio have been publicly available since 1973. Since the Internet did not exist in the Apollo era, NASA has only recently provided digital files for some of those earlier missions. The Apollo 10 audio clips were uploaded in 2012, but the mission’s audio recordings have been available at the National Archives since the early 1970s.

“As for the likely source of the sounds questioned in the television program, Apollo 10 Lunar Module Pilot Gene Cernan told NASA on Monday, ‘I don’t remember that incident exciting me enough to take it seriously. It was probably just radio interference. Had we thought it was something other than that we would have briefed everyone after the flight. We never gave it another thought.’”

(Bold emphasis mine.)

So there you have it, right from the moonwalker’s mouth. (LM pilot Cernan would later become the “last man on the Moon” during Apollo 17 in 1972.)


Transcript of Apollo 10 (Source: JSC)
Transcript of Apollo 10 (Source: JSC)

It’s worth mentioning that Al Worden, who was not on Apollo 10 but did fly around the Moon as CM Pilot on Apollo 15, was one of the talking heads for the NASA’s Unexplained Files segment and was made to appear that he suggested something otherworldly may have taken place—even though he says on his own website that he doesn’t believe in UFOs.

Also, based on a little more research, it turns out Apollo 11 CM pilot Michael Collins encountered these same noises just a couple of months later. He describes them in his book Carrying the Fire:

“There is a strange noise in my headset now, an eerie woo-woo sound. Had I not been warned about it, it would have scared the hell out of me. Stafford’s Apollo 10 crew had first heard it, during their practice rendezvous around the Moon. Alone on the back side, they were more than a little surprised to hear a noise that John Young in the Command Module and Stafford in the LM each denied making. They gingerly mentioned it in their debriefing sessions, but fortunately the radio technicians (rather than the UFO fans) had a ready explanation for it: it was interference between the LM’s and Command Module’s VHF radios. We heard it yesterday when we turned our VHF radios on after separating the two vehicles, and Neil said that it ‘sounds like wind whipping around the trees.’ It stopped as soon as the LM got on the ground, and started up again just a short time ago. A strange noise in a strange place.”

A strange noise in a strange place… nothing more.

It’s also worth noting that very similar “whistling sounds” were picked up by the Cassini spacecraft’s Radio and Plasma Wave Science Instrument in 2003, created by the planet’s powerful magnetic field. Listen to those here.

Voyager 1 also recorded “sounds” created by fluctuations in the plasma environment beyond the heliosphere in 2013, as have several other spacecraft as they encountered various worlds in our Solar System.

Perhaps in space no one can hear you scream, but if you’re dialed in to the right frequency you may pick up some spooky tunes!


*Note: I’m actually one of the talking heads for season 3 of NASA’s Unexplained Files! Although I wasn’t included in the premiere episode, you may see me on a later show. I can confirm that I only shared actual information regarding the events I covered and refused to “wax conspiratorial,” but I have no idea how the final edits turned out.


  1. I own a copy of Collins’ book and remember that explanation. No mystery there – the only surprise being why the issue has been made into anything now, when the actual phenomenon was fully understood and explained when it happened in 1969.

    Liked by 1 person

  2. Jeff Barani says:

    Tanks for this article Jason. I did not this long story short to Apollo 10.
    And indeed, these sounds created by fluctuations in the plasma environment beyond the heliosphere or various worlds encountered are really creepy !!
    Jeff Barani from Vence (France)


  3. wow I like your article, very inspiring, and thank you for your post


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