THE SAUCER SHIP

It could be. And it could be just an old version of the SJs Galactic Taxis

I don't think so. I think it may be and enveloping complex that contains the Juggernaut. In [i]Prometheus[/i] it's buried.

the thing is, the horse-shoe shaped craft is just too distinctive to look like a saucer, even from the most manipulated angles there is a thread on here that suggests that the Engineer's craft, spins so fast, that it appears to have a saucer like look, while the center of the craft remains still giving the appearance that it's a saucer, when in fact its the familiar craft we have all grown to know in any case, i think that showing us the creation of life here on Earth, via some extraterrestrial entities is really something to behold can not wait...!

Ive seen an image with a spiral shaped structure which looks to be underground and i assumed had the derelict hangar at the top this is where i think the crew go and the various chambers are along the way. I still think that its the croissant from the back you can make out a little detail and scale wise i fits with the size of that rather than a larger body which it would be held within. that said who knows.

I think that they're diferent ships. Like Ridley scott said before, the derelict/juggernaut is a bomber and the saucer is the terraforming ship that created the humanity.

I would go for that the Saucer is whats burried under LV223's surface and thats whats openeing up in some scenes where Shaw tries to jump across from the chasm its created. Problem is while they stopped a Juggernaught/Derelict how are they going to stop the Mother Ship. If thats not the case then it would be interesting to find out what that saucer is.