SpaceX’s mega Starship rocket has blasted off on its fourth test flight. The 400-foot rocket was empty as it soared above the Gulf of Mexico and headed east Thursday. The spacecraft on top is aiming for a half-lap around the planet with a splashdown in the Indian Ocean. The first-stage booster dropped successfully into the gulf, without blowing up this time. SpaceX is working to avoid explosions by controlling the descents. NASA and SpaceX’s Elon Musk are counting on Starship to get humanity to the moon and Mars. SpaceX’s mega Starship rocket has blasted off on its fourth test flight. The 400-foot rocket was empty as it soared above the Gulf of Mexico and headed east Thursday. The spacecraft on top is aiming for a half-lap around the planet with a splashdown in the Indian Ocean. The first-stage booster dropped successfully into the gulf, without blowing up this time. SpaceX is working to avoid explosions by controlling the descents. NASA and SpaceX’s Elon Musk are counting on Starship to get humanity to the moon and Mars. AP Technology and Science