During their pioneering voyage Michael Collins made note of the “strange electronic-sounding music” Neil Armstrong played on cassette. You’re on the Sound Beat.
So, wherever you are right now, you’re listening to the same song Armstrong played in the command module between Earth and Luna. You’re listening to Moon Moods by Les Baxter, featuring the theremin playing of Dr. Samuel Hoffman. They’re from the appropriately-titled album Music out of the Moon, a 1947 album of six songs on three 78s.
Considering the intensity of the Space Race, it was certainly an interesting selection. The theremin is an electronic instrument, and a Russian one, named for inventor Leon Theremin. It evolved as a product of government research into proximity sensors shortly before the outbreak of the Russian Civil War in 1919. It’s so Russian Lenin took lessons on it (that’s Vladimir Ilyich, of course, not Yoko’s husband).