Endeavour's heat shield may need repair

Houston, Aug 13: NASA got a closer look at a small, but deep gouge in the belly of the space shuttle Endeavour and said it had not decided whether it needed a repair to ensure the ship's safe return to Earth.

Shuttle astronauts used a robot arm to scan the damage with a laser that provided a three-dimensional view showing that the three-inch gash penetrated all the way through the thin tiles that protect the shuttle from heat as it flies through the atmosphere before landing.

Mission management team chairman John Shannon said NASA needed to do more tests before making a decision to repair the damage, caused by a chunk of foam that fell off the shuttle's fuel tank about a minute after liftoff from the Kennedy Space Center in Florida on Wednesday.

''The gouge goes pretty much through the entire thickness of the tile,'' he told reporters at Johnson Space Center yesterday. ''I don't have any idea whether a repair will be required.'' Computer simulations and experiments with model tiles damaged to mimic Endeavour's condition will be conducted to determine if the hole poses a threat to the orbiter's structure, Shannon said.

During atmosphere re-entry, temperatures at the rear of the ship where the damage is located can reach as high as 2,300 degrees Fahrenheit (1260 degrees Celsius). If a repair is needed, spacewalking astronauts will be sent out to patch it up, he said.

The damage revives concerns that the shuttle fuel tanks, which were twice redesigned after the fatal 2003 Columbia accident, may need more work before NASA will clear future missions for flight.

Columbia was destroyed because of shield damage caused by falling foam insulation during launch that hit the ship's wing. The shuttle broke apart as it plowed through the atmosphere for landing 16 days later, killing all seven astronauts aboard.

NASA officials said because of the success of a new electrical system being tested, Endeavour's planned seven-day stay at the International Space Station will be extended by three days so extra work can be done to prepared the 100 billion dollars complex for new additions.

Endeavour arrived at the station on Friday and on Saturday, spacewalking astronauts installed a new beam on the station's structural backbone.

Today, astronauts will make the second of four planned spacewalks, this one to replace one of the outpost's gyroscopes, which keep the station properly positioned without the use of gas-guzzling rocket thrusters.

Reuters>