We finally have a trailer for James Gray’s “Ad Astra,” a long-delayed artsy sci-fi epic in space. I have been an advocate of Gray’s classicist style for quite some years now, or ever since I saw his excellent 2007 family saga “We Own the Night,” but, more importantly, the immaculate 2009 romance “Two Lovers.” He followed those up with “The Immigrant” and “Lost City of Z,” both critically acclaimed works. However, “Ad Astra” is a whole other monster. The just-released trailer has parallels to Nolan’s “Interstellar,” Coppola’s “Apocalypse Now” and Cuaron’s “Gravity.”