Space music doesn't get as much credence as it use to. Don't tell anyone you like it, or you'll be seen as a tripped out hippie freak. Even more so than traditional ambient, space music is something to float to. It's more about intensity, rather than calmness, it's more about filling all the available space, rather than quiet meandering.
Klaus Schulze is mostly known for being in what seems like half of the Krautrock bands in Germany in the 70's. He was extremely prolific as well, having been involved in over forty works since the late 60's. He has played with Tangerine Dream, Ash Ra Tempel, The Cosmic Jokers and Pete Namlook to name a few.
Irrlicht is his first solo album, fresh out of the guitar-based jams of Ash Ra Tempel. I believe that Schulze uses Irrlicht to display the magnitude of the creation of the Universe. Using mainly his organ, along with various other instruments, Satz: Ebene slowly builds momentum with spacey sound effects until it explodes into a fiery mix of swirling oscillations and vividly ethereal organ drones over the twenty minutes. Satz: Gewitter is almost the calm after the flourish, as it drifts along in the aftermath. Satz: Exil Sils Maria is unrelated to the last two pieces, and is just an creepy but enjoyable drone, tempered by small sections of almost-earthly music towards the start. They soon disappear, leaving strange noises and sweeping wind washes. Apparently, the whole song was recorded and then reversed, leaving it as it is.
I can't count how many different ambient genres Irrlicht would have influenced, everything from space music, to dark ambient, to drone. And even more incredibly, it was done without a synthesiser, a staggering thought. Even though it is an technically an ambient album, it takes the ambient sound and rams it up to eleven, creating a potent maelstrom of weightlessness and presence.