At then end of Prometheus,
after the "Engineer" was attacked by the huge "face-hugger"
I had expected the Engineer to go back to his ship and sit in that large chair he previously used when attempting to leave the planet. I assumed this because in Alien the crew of the Nostromo found
the "Space Jockey" in a similar ship with his chest cage exploded from the inside, obviously killed by an alien "hatching" (or whatever you call it).
Isn't the crashed alien ship the same ship that the crew of the Nostromo found? If so, then where is the Space Jockey?