The space shuttle Endeavour has undocked from the International Space Station and is headed back to Earth. The shuttle and its six-member crew are scheduled to land in Florida at 0316 a.m. (local time) on Monday.The latest mission saw the successful installation of the Tranquility Node, a spacious addition that includes the cupola seven-window observation deck. The commissioning of Tranquility marks the last major component of the space station.