The next space shuttle crew will use a sensor-laden boom to scan their ship's wings for damage from tiny meteorites and bits of space junk, a NASA spokesman said on Wednesday.
The procedure, which will be conducted near the end of Discovery's planned 12-day flight, could become standard for all remaining shuttle missions before the fleet is retired in 2010.
Only one shuttle has flown since the 2003 Columbia disaster. Columbia was lost and its seven crew members killed during re-entry due to wing damage caused by a piece of foam insulation that fell off the shuttle's fuel tank during launch.
"Doing a late inspection is one of the ways that you increase the likelihood that you have a clean vehicle," said NASA spokesman Kyle Herring of the Johnson Space Center in Houston. "It's the length of time in space that drives up the risk of impacts."
If the inspections turn up any dents, holes or other damage, the shuttle crew could attempt in-flight repairs, depending on the location and the severity of the damage, Herring said.
Primarily, however, the inspection will allow engineers to quantify a risk that has never been nailed down. Space shuttles have previously returned to Earth with obvious, though minor, debris damage.
After the loss of the Columbia, NASA developed tools and techniques to scrutinize the ships prior to atmospheric re-entry. The board that investigated the disaster also identified micrometeorite and orbital debris impacts as an ongoing flight risk.
Additional work planned during Discovery's mission prompted managers to place on hold a spacewalk designed to test materials to plug holes in damaged wing panels during flight. NASA now plans to conduct the spacewalk only if the shuttle has enough supplies to stay in orbit for an extra day.
NASA is targeting Discovery's launch for July, though the agency is still analyzing fuel tank design changes to prove they are safe.
The fleet was grounded again after more foam insulation fell off the tank during Discovery's July 2005 liftoff.