The Apollo Project succeeded in landing the first two men – Neil Armstrong and Buzz Aldrin – on the surface of the Moon more than 50 years ago. The two legendary astronauts achieved President John F. Kennedy’s goal of landing humans on the surface of the Moon by the end of the 1960s and putting an end to the space race with the Soviet Union. Earlier that year, Apollo 10 was launched as an “official dress rehearsal” to test the technology and became the second US spacecraft to orbit the moon.

But the DarkDocks YouTube channel revealed how an event during the mission had been classified for years.

The narrator said: “Apollo 10 was launched in May 1969, and was a rehearsal for the actual landing on the moon.

Its primary purpose was to test all components and procedures that would be used later in Apollo 11.

“Not much was known publicly about the mission, other than that it went rather smoothly.

But the mission’s bewildering materials were released decades later.

The video and audio captured included shots of shaky vehicles, static-filled breaks and a whistling accident – which the astronauts described as “extremely disturbing.”

In the recording, an astronaut can be heard saying, “This music sounds like alien, right?”

Another adds, “Well, that’s strange music for sure. Nobody will believe us.”

Over the course of an hour, they mentioned the noise multiple times.

Read more: The mystery of the moon landing: A Soviet “device” was spotted on the surface after a “secret” mission

“If I heard something there it would definitely scare me,” admitted Mr. Worden, who passed away in March.

At the time, conspiracy theorists speculated that the noise was related to UFO coverage.

But, according to space journalist James Auberge, the sound was most likely a radio interference between the command module and the Lunar Lander.

Describing it as an “outer space” may have been due to a preparation – a phenomenon in which exposure to a single stimulus affects the response to a subsequent stimulus, without conscious direction or intention.