Elon Musk is joining his space exploration and artificial intelligence ventures into a single company before a massive planned initial public offering for the business later this year.

Elon Musk addressed a crowd at a Texas SpaceX facility, telling listeners about the “purpose of SpaceX.” That purpose, it turns out, is to “make ‘Star Trek’ real.” “We want to make Starfleet Academy real, so that it’s not always science ...