By MARCIA DUNN, AP Aerospace Writer CAPE CANAVERAL, Fla. (AP) — It all comes down to the final six minutes of a six-month journey to Mars. NASA's InSight spacecraft will enter the Martian atmosphere at supersonic speed, then hit the brakes to get to a soft, safe landing on the alien red plains. After micromanaging every step of the way, flight controllers will be powerless over what happens at the