Space Jockeys were destroyed by their own evil experimentations, the mutations were the ones who overan the Space Jockeys and forced them to escape little did they know that the Predator were also after their cargo... the eggs in stasis.. predator knew very well what was occuring on the surface of the Space Jockey home planet as the xenomorphs ran wild killing everything in sight. They saw the opportunity to take the specimen and use it on earth thousands of years ago... the space jockeys sent their rescue message from LV-426 10,000 years ago the Predators arrived , Space Jockeys died, and Aliens escaped...