Originally Posted by Icedhope
I'm assuming this is taking place on LV-426.
It's unknown at this point whether 'Prometheus' takes place on LV-426 or not. It's also unknown as to whether the Space Jockey craft seen in the trailer is the same one as the derelict spaceship seen in 'Alien' (although it's undeniably the same class of ship).
Remember in 'Alien', when the crew are analysing LV-426 and they mention that it appears to be in a Primordial state? Well, some people have theorised that the planet that 'Prometheus' takes place on will be terraformed by the Space Jockeys at some point during the film, thus starting the process of building up an atmosphere and therefore converting the planet to a primordial condition (explaining the difference in appearance between the look of the LV-426 in 'Prometheus' and in 'Alien').
On the other hand, prior to Lindelof caming on board and reworking Spaights script into 'Prometheus', back when it was still a direct prequel to 'Alien'; Ridley Scott mentioned that the film took place in the Zeta 2 Reticuli system, which is the same system where LV-426 resides. It's possible that seeming as LV-426 was a moon, that 'Prometheus' takes place on the larger planet of which LV-426 was in orbit.
Either way, Lindelof has stated that 'Prometheus' won't end with the derelict seen in 'Alien' crashing and there being a bunch of eggs on board. Apparently, any sequel to 'Prometheus' would be its own thing and not
the original 'Alien' film.
In short; we'll just have to wait and see.