Declassified recordings of the astronauts' conversations during the Apollo 10 mission revealed that they heard strange music while flying on the dark side of the moon, but decided not to report it to the Mission Control Center. The incident was described in detail in an episode of NASA's Unexplained Files of the online scientific TV channel YouTube Science, and The Verge briefly reports on it.
The Apollo 10 mission aimed to carry out various operations that were to be carried out during the landing, including undocking and subsequent docking of the command and lunar modules.
Astronauts heard unusual sounds during undocking - during this operation they were deprived of communication with the Earth for an hour. The astronauts discussed the "music" among themselves, noting its strange sound and the need to determine its source. One of the crew members called the sounds "music from deep space", the other compared it to a whistle.
Shortly before the restoration of communication with the Earth, the astronauts discussed whether they should tell the leadership about this experience - and decided to remain silent. “No one will believe us,” one of the astronauts remarked. Apparently, this decision was due to the peculiarities of NASA's ethics. The pilots were wary of reporting strange and inexplicable phenomena that happened to them during the flight, because they were afraid that they would be deprived of the opportunity to go back into space.
As the reason for the strange sounds, the authors of the episode point to charged particles, which led to interference in radio communications (with similar phenomena, the Cassini probe collided near Saturn). However, the source of these particles could not be the Moon, since the Earth's satellite has no atmosphere. It is also likely that the "music" originated from normal communication interference between the two modules.
