Forty years ago today, when humans first set foot on the moon, Pink Floyd was helping the BBC with its live coverage of the event. While a team of scientists in one studio offered commentary, the band was in another, playing a live score to accompany the grainy black-and-white images flickering on the screen.

Pink Floyd guitarist David Gilmour tells The Guardian, "They were broadcasting the moon landing, and they thought that to provide a bit of a break, they would show us jamming. It was only about five minutes long. The song was called 'Moonhead.' It's a nice, atmospheric, spacey, 12-bar blues."

Here's the unreleased track:

This isn't the original video, with music as everyone saw and heard it. It was apparently produced by a fan, using a bootlegged copy of the song.