KENNEDY SPACE CENTER, Fla. — For the second space shuttle flight in a row, NASA has found heat damage on a critical O-ring seal in a rocket booster used by Discovery this month.
It is the same nozzle joint in which the problem occurred on Atlantis, only this time it's in the right booster, NASA said Wednesday.
In both cases, hot gas from burning rocket fuel singed the primary rubber seal in the joint but did not pass beyond the seal. Neither of the shuttles nor crews were in any danger, NASA officials said.
Engineers will evaluate all the data before recommending whether it's safe to fly Endeavour next week.
A leak in a joint in a solid rocket booster caused Challenger to explode shortly after liftoff in 1986. A nozzle failure in this case could cause the shuttle to veer dangerously off course during the first two minutes of flight.
Atlantis blasted off June 27 on the first shuttle docking mission with Russia's space station Mir and returned July 7. Discovery was launched July 13--at six days the shortest gap ever between U.S. human spaceflights--and returned Saturday.
NASA did not learn of the problem with Atlantis' booster until four days into Discovery's flight, prompting questions about whether the space agency should allow more time between missions.
Shuttle Director Bryan O'Connor said managers will decide by early next week whether the fleet should be grounded.