Commissioned as a soundtrack for Al Reinert’s 1989 documentary film on the Apollo space program For All Mankind but first released in 1983 as a standalone album due to Reinert’s continuing work, Apollo is an apex point of Brian Eno’s ambient work. Collaborating with his brother and longtime musical partner Lanois, Eno oversaw an exquisite series of pieces capturing a sense of deep, dreamy and mysterious space. “An Ending (Ascent)” is the album’s most famous composition, but the steel guitar of “Deep Blue Day” comes pretty darn close.