SOUTH PADRE ISLAND, Texas (AP) — SpaceX has called off its first launch attempt of its giant rocket. Elon Musk and his company had planned to launch the nearly 400-foot Starship rocket Monday morning from the southern tip of Texas, near the Mexican border. SpaceX postponed the launch because of a problem with the first-stage booster. No people or satellites were aboard for this attempt. There won’t be another attempt until at least Wednesday. The company plans to use Starship to send astronauts and cargo to the moon and, ultimately, Mars.