One of the directors scored the film. There is a hint of Zimmer in there from memory, but there's also a love theme (or perhaps a hero theme, depending on your POV) that goes on a journey.
The Heinlein source material is wonderful and beautifully sad. Had the direction been less conventional (think John Frankenheimer's "Seconds") then this would've been a great film. But the conventional treatment by the directors and - yes - the disappointing "sonic wallpaper" soundtrack sunk this down to being just okay.
