“You hear that, that whistling sound?”
“Yes.”
“Whooooooo...”
Two months before astronauts landed on the Moon for the first time in 1969, they circled around it in orbit during the Apollo 10 mission for reconnaissance.
On the far side of the moon, cut off from contact with the NASA base on earth, the astronauts heard haunting “space music” on their radio transmission.
Although the audio files have been available in the National Archive since the early ‘70s, they were publicized for the first time this week on the Science Channel’s series, “NASA’s Unexplained Files.” (The music comes in around the 2:04 mark).
The sound probably didn’t originate from aliens, and a NASA engineer on the Apollo 10 mission attributed to radar interference.
“'I don’t remember that incident exciting me enough to take it seriously. It was probably just radio interference,” Lunar Module Pilot Gene Cernan said on Monday. “Had we thought it was something other than that we would have briefed everyone after the flight. We never gave it another thought.”
Near planets with large magnetic fields, eerily suggestive “space music” can be easily heard. In 2005, NASA released a 1-minute long audio of the radio emissions they captured from the polar regions on Saturn from the Cassini spacecraft.
http://www.nasa.gov/wav/123163main_cas-skr1-112203.wav
A similar recording made from sound captured by the Voyager was compiled in a 1990 CD, provided below.