> I'd wager it's a pretty international workforce at SpaceX
You would lose the bet. From their job application page:
"To conform to U.S. Government space technology export regulations, applicant must be a U.S. citizen, lawful permanent resident of the U.S., protected individual as defined by 8 U.S.C. 1324b(a)(3), or eligible to obtain the required authorizations from the U.S. Department of State."
It's that way across the aerospace industry. Most space technology is classed as "munitions" because of ballistic missiles and spy satellites. So "export" is restricted, and that includes hiring foreign workers. It even applied to the Space Station program, which was international by design. Those of us at Boeing couldn't talk to our counterparts in partner countries. Stupid but true.