听力原文： The space shuttle Discovery made a rare night landing at the Kennedy Space Center early on Thursday．The night landing，the 11th in the Center’94 shuttle missions，ended a 10—day mission to outfit the orbiting International Space Station． Although the spacecraft created a sonic boom that could be heard along much of Florida's eastern seaboard，witnesses on the ground could not see the orbiter until it was directly over the runway lights． Scattered showers off the Florida coast had threatened to postpone the shuttle's return，but forecasters gave the green light when they decided no rain would fall within 48 kilometers of the space center． The space shuttle Discovery completed its mission for about ______ days before it returned to Kennedy Space Center.