Found this on Tumblr. Bought the song and sub’ed to Pentatonix’ You Tube feed (I had already sub’d to Stirling’s). I first heard this song on AMC, IIRC during ads for “Defiance”. Maybe it was “Falling Skies.”
…bouncing otters! You’re welcome. (h/t to Diane Duane on Tumblr)
…performed by Cmdr Chris Hadfield. It’s marvelous.