CAPE CANAVERAL, Fla., July 30 (UPI) -- NASA officials Saturday said space shuttle Discovery is safe for re-entry and announced the shuttle's mission will be extended by one day.
Future shuttle flights are on hold as National Aeronautics and Space Administration engineers try to understand the reason foam broke off Discovery's fuel tank during launch Tuesday.
Wayne Hale, the deputy shuttle program manager, says heat protective tiles and thermal blankets on the shuttle were not damaged, but more tests will be carried out.
The extra day will give the crew time to re-supply the international space station and help with maintenance.
Two astronauts spent nearly seven hours outside space shuttle Discovery Saturday.
Steve Robinson and Soichi Noguchi, on their first ever spacewalk, tested techniques for fixing shuttles while in orbit using common tools like a caulk gun to repair tiles and panels.
The techniques were developed after space shuttle Columbia disintegrated as it re-entered the atmosphere in 2003.
The two also repaired an antenna on the international space station's global-positioning system.
The second spacewalk of Discovery's mission is scheduled for Monday.