SpaceX actively recruits from LinkedIN. I was contacted by a SpaceX recruiter on LinkedIN and after speaking with the recruiter, several phone interviews were scheduled. After two formal phone interviews I was offered a face to face interview at their headquarters in Hawthorne, CA. They flew me out and paid for the flight, a rental car, hotel room, and all meals. The place is impressive and you go through several rounds of interviews. In the first round I was asked to prepare and deliver a presentation on some of my work and after that if the team decided you might be a fit you were able to continue to a paper test. If you passed the test, you were invited for one on one interviews.