"We said, 'Stop. Let's go ahead and extend the schedule, and let's figure out what the right way is to go about (meeting the recommendations of the Columbia accident investigators).' We're not going to be driven by the calendar. This is going to be a milestone-driven event." Source: NASA Administrator Sean O'Keefe, announcing that the space shuttles' return to flight won't happen before March, 2005. Redesigning the space planes' external fuel tanks, along with new problems found in the rudder-speed brake assembly and CAIB-mandated restrictions that require daylight for both the launch and the external fuel tank drop have all conspired to keep the three remaining shuttles grounded in the wake of the Columbia disaster.