WASHINGTON : The U.S. Federal Aviation Administration on Monday said it closed out a review into SpaceX's explosive Starship test flight in January, while another investigation into the rocket's subsequent testing explosion in March remains open. SpaceX's last two test flights of Starship, a 400-foot-tall (122-meter-tall) rocket system at the center of Elon Musk's goal to colonize Mars, ended with explosions during similar phases of flight, representing a novel setback in SpaceX's flagship