One of my favorite moments in 'ALIEN' is when Dallas, Kane and Lambert venture into The Derelict Ship and discover the Space Jockey; the fossilized bones of an unknown alien species. I LOVE the Space Jockey, and it's never explained who it was, where it came from and why - and that was just fine. The MYSTERY of the Space Jockey added to the fun - there's a lot of The Unknown in Space, and that was one of the points of the film.
The Space Jockey was created by H.R. Giger, who also created the Alien Creature. Both had visual aesthetics that he dubbed "BIOMECHANICAL", which is prevalent in his paintings and sculpture. The link of Giger established (in my mind at least) that wherever the Derelict Spacecraft came from, it was from a sector of the universe that was Biomechanical. Just imagine: An entire area of Space that was all Giger/Biomechanical! I still get giddy at the thought.
In ‘Prometheus’, the fossilized bones we saw in 'Alien' have been retconned into space suits. For years Ridley Scott referred to them as bones, but in the last decade he “pulled a Lucas” and said, “oh, you thought those were bones? No, it was a space suit”. Boba Fett is a clone, Darth Vader built C-3PO and without microscopic organisms called ‘Midichlorians’ in your blood, you cannot speak to the Force. Instead of tall biomechanical creatures, Space Jockeys are now just really tall, hairless, super-muscular humans. Yes, they can be called “humans" because their DNA is an exact match to ours. In 'Alien' the Space Jockey represented the eerie vastness of space and the fear of the unknown. By directly linking the Space Jockeys to Earth and Humans, they've greatly narrowed that concept.
'Prometheus' took what was once one of the coolest, imaginative creatures in Film and replaced it with a Star Trek alien race in a Giger costume. For this Alien Fan, 'Prometheus' absolutely ruins the Space Jockey. To activate Engineer Ship, play Flutophone.