"We were actually quite surprised to hear that we had some large pieces of debris fall off the external tank," Cmdr. Eileen Collins said.
However, Collins said the debris was was unexpected and added,
"I don't think we should fly again unless we do something to prevent this from happening again."
NASA has said it plans to inspect the shuttle Discovery and heat-resistant tiles that protect it upon re-entry to Earth, but Collins noted
shuttles routinely suffer minor tile damage during launches, CNN reported.
The crew was using the robotic arm Friday to help inspect a
few areas that may have been damaged -- the nose landing gear, leading edges of the shuttle's wings and the belly of the orbiter.
A similar launch accident led to the breakup of shuttle Columbia when it re-entered the Earth's atmosphere Feb. 1, 2003, in which seven astronauts died.
Earlier Friday, a fresh cargo module ferried into orbit by Discovery was installed by astronauts in the International Space Station.