I’m a bit hesistant with this post but the footage seems to be authentic. IMDB user EverardoGuzman01 has just posted up this footage which he claims to be from the Prometheus trailer:
He says this is just a 10 second clip of the trailer which he also provided a full description of it which I’ve been asked to remove by Fox. I noticed what appeared to be a shot of the flamethrower scene we’ve seen leaked images of, the spacesuits we’ve already seen and what appeared to be the scene depicted in the official production still. Thanks to reuben for the link.