Strange “musical” sounds recorded during Apollo 10 mission in 1969 now public

NASA has released a recording of unusual "musical" sounds the Apollo 10 astronauts reported in 1969 while on the far side of the Moon, out of radio contact with the Earth. The Science Channel broadcasted a story behind the strange sounds on February 21, 2016, as a part of a series called "NASA's Unexplained Files".

The sounds Apollo 10 astronauts heard were recorded and later transmitted to mission control in Houston. A text transcript was released in 2008 while the audio has not been made public until now.

Video courtesy of Science Channel

The astronauts Thomas Stafford, John Young and Eugene Cernan, who were onboard the spacecraft, thought the sounds were quite strange at the time:

"Did you hear that whistling sound too?"

"Sounds like — you know, outer-space type music."

"I wonder what it is."

This conversation was held between Cernan and Young while the spacecraft flew around the far side of the Moon.

According to NASA, the sounds could not have been of alien origin, and an engineer from the US space agency thinks they likely resulted from an interference of radios that were close to each other in the lunar module and the command module.

Video courtesy of Science Channel

"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."

Michael Collins, the pilot of Apollo 11 and the first person to fly around the far side of the Moon by himself, said he heard "an eerie woo-woo sound" as well. He, however, accepted the proposed explanation of radio interference. He was warned about the noises before his space journey. Collins described in his book, Carrying the Fire: An Astronaut's Journeys: "Had I not been warned about it, it would have scared the hell out of me. 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."

Al Worden, Apollo 15 astronaut, disputed official explanation, saying: "The Apollo 10 crew is very used to the kind of noise that they should be hearing. Logic tells me that if there was something recorded on there, then there's something there."

Mission transcripts can be found here.

Featured image credit: Science Channel