The U.S. space agency says the space shuttle Endeavour can safely return to Earth next week without repairs to the orbiter's damaged exterior heat shield.
After nearly a week of analysis, NASA flight managers said late Thursday they have concluded that a small gouge on the shuttle's exterior is not a threat to the spaceship or its crew, and is unlikely to cause further damage. Some of Endeavour's thermal protection system tiles were damaged during last week's liftoff.
On the astronauts' next spacewalk, on Saturday, NASA says the crew will perform scheduled assembly work on the International Space Station, instead of working on the heat shield.
The Endeavour crew had already been begun preparing for a possible orbital repair spacewalk - an unprecedented procedure that was considered risky in itself.
The astronauts also conducted a "classroom in space," led by teacher-turned-astronaut Barbara Morgan and fellow mission specialist Alvin Drew, together with students at NASA's Challenger Center for Space Science Education in Alexandria, Virginia, just outside Washington.
On Wednesday, Endeavour's crew cut short a third spacewalk when astronaut Rick Mastracchio found a small hole in his glove. Officials said he was in no danger, but flight controllers ended the spacewalk as a precaution.
Before returning to the shuttle, the astronauts completed the major tasks of the spacewalk. They relocated an antenna and installed a new signal processor on the station.
Some information for this report provided by AP and Reuters.