As SpaceX prepares for its next Starship test flight, the company’s prospectus underlines how critical that vehicle is to its ambitions.

Elon Musk's SpaceX this week will launch its next Starship flight, release the prospectus for its $1.75 trillion IPO. Space stocks pare gains.

Starship test flight has been building for weeks, with space enthusiasts closely watching every update from SpaceX. The company’s massive Starship rocket, the largest and most…