Doyle Rice

USA TODAY

NASA astronauts in orbit around the moon in 1969 heard a whistling sound described as "outer-spacy," "weird," and "eerie."

Recordings of the strange sounds are featured on the Science Channel show "NASA's Unexplained Files," which will air Tuesday night at 10 p.m. ET.

The sounds were discussed in a conversation between Apollo 10 astronauts Eugene Cernan and John Young as their craft flew around the far side of the moon, CNN said.

Though the Apollo 10 audio and transcripts were not officially classified, there was "no way to get them to the public before the Internet," the NASA History Office clarified Monday morning on Twitter.

The flight crew heard the sounds while on the dark side of the moon and while out of radio contact with NASA ground control, according to a report from the E.W. Scripps National Desk.

Apollo 11 astronaut Michael Collins, in a book published years later, said the noise was just interference between the lunar module and command module's VHF radios, the Weather Network said.

Apollo 10 was the fourth manned mission in the Apollo program, and launched on May 18, 1969, CBS reports.

Here comes the snow moon!

According to TV Weekly Now, the show NASA's Unexplained Files dives into the mysteries of some of NASA’s most curious missions to explore stories of engineering achievement and human endurance

You can read the original transcripts on this page from the NASA history office.