How on earth did Starship Troopers get greenlit?

Independence Day came out the year before and was a massive success, so doing another alien invasion film wasn't seen as a risk. Also keep in mind the 90s was an era when R-rated movies were still quite lucrative (Terminator 2, Saving Private Ryan, and the Matrix come to mind). Starship Troopers was basically just "Aliens" (a massive success) with some satire thrown in.