Discovery's astronauts are ready for the first night launch of a space shuttle in four years, the mission's commander said Wednesday.
"For us, we don't view it as a really large change," said Discovery commander Mark Polansky, whose crew could blast off to the international space station as early as Dec. 7.
NASA required daylight launches for the first three shuttle missions after the Columbia disaster in 2003 to allow clear photography of the external fuel tank in case debris fell from it. Foam breaking off the tank and striking Columbia's wing at liftoff was blamed for the disaster which killed seven astronauts.
But the U.S. space agency needs to start launching space shuttles at night to meet its schedule to complete construction of the space station by 2010, when the shuttle program comes to an end. NASA officials said radar should be able to spot debris falling from Discovery's tank, and two in-flight inspections should reveal any damage to the spacecraft.
Discovery's seven astronauts are at Kennedy Space Center for a week of drills. On Thursday, they plan to don their spacesuits, strap into the space shuttle and run through a practice countdown.
During their 12-day mission, they will rewire the space station and rotate out a crew member at the orbiting space lab.