Photo: Francois Duhamel / Twentieth Century Fox
Director James Gray’s lush new space opera Ad Astra is essentially two parallel films. One is a visually inventive science fiction odyssey that imagines near-future space travel as the new Wild West frontier. The other is a tepid father / son drama that Gray and his co-writer, Ethan Gross, don’t even try to elevate above the most threadbare clichés. The latter film doesn’t entirely drag down the former, although it seems to be trying its ready best. That does mean, however, that Ad Astra is poised to kick-start the most passionate style-vs.-substance debate cinephiles have had in years. Individual viewers will probably find that where they fall on that well-worn cinematic divide will determine how much they appreciate this visually…