As we all know, it has that typical late 60s "rock group with string section added on" sound. I recommend it here mainly because I *love* the change in mood and minor tonality that comes with line "Ground control to Major Tom, your circuit's dead - There's something wrong" which comes after "Tell my wife I love her very much - she knows". The diminished 7th chord under the words "Major Tom" is, well, sublime.

The song was produced by Gus Dudgeon who went on to produce most of Elton John's classic material, and features Rick Wakeman amongst several subsequently famous session musicians. The Wikipedia articles on the track and the album it came from are interesting, well-written, and seem well-researched (unless anyone wants to disagree).