There were 5 stages I had to get through, and each one goes deep into its content. There's an initial phone screen, then a technical dive into one of your projects with the Team/Project Lead, then a 48-hour Tech Test which will have some assignment that you have to figure out and optimize, then an on-site presentation of your assignment solution to the team, and then two on-sites starting with one coding run 1-on-1 with an engineer, and then a behavioral final 1-on-1 interview, both 1 hour long. I got to the Tech Test but did not pass. The HR person of the phone screen was way more involved in the internal engineering of SpaceX than HR anywhere else, the technical dive was tough questioning from the technical lead who would poke and poke and keep poking into your project's details until he found the limit of your knowledge, and the tech test was a hypothetical satellite-user linking problem which took some serious thinking, algorithm design, and optimization. Some of the tests weren't fully solvable, so you had to optimize as much as possible.