Who knew Neil Armstrong's heartbeat would make such a smooth bass line?

On July 20th, 1969, the astronaut became the first person to set foot on the moon, and uttered these famous words: "That's one small step for man, one giant leap for mankind."

Armstrong spent two-and-a-half hours exploring the lunar surface, and somewhat surprisingly, his heart rate during the mission was much lower than expected -- even lower than the heart rates of some scientists back at Mission Control. It spiked only once to a rate of 160 beats per minute at the end of the spacewalk.

While listening to a radio program about the moon landing, even German-based singer-songwriter Louise Gold became fascinated by Armstrong's steady beat, and decided to use it as the bass line in a new song -- turn up the volume and listen to it in the Youtube video above.

"It struck me then that this strong yet peaceful sound could be the perfect rhythm for a song," Gold told CNET.

She said John Lennon's "Oh My Love" fit well with how she imagined Armstrong must have felt on that historic day: "peaceful and exhilarated at the same time, a bit like being in love with someone and finding out that this person loves you back," Gold told online magazine Vice in an email.

The songwriter then mixed in a sample of data from NASA's Voyager spacecrafts that had been converted into melodies, and posted the cover on YouTube on July 16, 2014.

As YouTube user Gustavo Abanto pointed out in a comment, you can hear the heartbeats in the video at 2:10.