Ad Astra is a film of high pretensions, lofty ambition and some imagination, making it at the very least noteworthy in the bravery and flair. Brad Pitt’s Roy McBride is the latest man flung through time and space, following luminaries from 2001, Gravity and of course Interstellar. But it is Apocalypse Now that most closely reassembles the journey McBride finds himself…