As workmen put the finishing touches on the red carpet here in Venice this morning, a throng of press gathered for the first screening of Alfonso Cuaron‘s Gravity. The film began about 30 minutes after its scheduled start, and as the audience grew impatient for the lights to go down, there were mumblings of “Houston, abbiamo un problema.” But once things got moving, the room sat silent, completely engrossed. Sandra Bullock and George Clooney star in the 3D space odyssey that drew loud applause after a tight 90 minutes. It now has folks tossing around words like “astonishing” and “brilliant.” The tense sci-fi actioner sees Bullock and Clooney stranded adrift after debris hits their space shuttle. (Bullock also has a lot of alone screen time.) Cuaron, who makes use of his taste for long tracking shots, is being largely praised here in Venice with some now even wondering why the film wasn’t in competition. Cuaron has won prizes in Venice before, for 2001’s Y Tu Mama Tambien and for 2006’s Children Of Men. Gravity, co-written by Cuaron and son Jonas, officially opens the festival tonight with director and stars in tow. Warner Bros opens it in the U.S. on October 4; it’s also playing at Toronto.