It's a good song, though one I'm personally sick of, but the references were not overtly about drugs. It wasn't a hit in America until some years later, but a British hit in '69... it's release was timed to coincide with the moon landing, it's obviously about an astronaut getting lost in space. Depending on one's perspective, it's either a tribute to that event, or a cynical, novelty tune designed to cash in on the publicity surrounding that event.

Like I said in my review of Ashes to Ashes, I don't believe that these songs were about drugs. I believe they were about sliding into mental illness - a change of venue.