The space shuttle Endeavour landed safely in Florida yesterday after a 13-day mission marred by damage to the spacecraft's heat shield that led to a lengthy debate about whether to risk returning to Earth without fixing it.
The dinged-up spacecraft touched down at Cape Canaveral at 12:32 p.m. after completing a 5.3 million-mile mission to the International Space Station.
NASA Administrator Michael D. Griffin said the damaged tiles "did very well on re-entry." After examining the gouged thermal tiles on the tarmac at Kennedy Space Center in Florida, shuttle Commander Scott J. Kelly said he was "a little bit underwhelmed by the size of the gouge. It looked rather small."
Two heat-resistant tiles on the underside of the shuttle were damaged on launch by insulating foam that fell off the external fuel tank. The cavity concerned experts because it cut through almost to the aluminum surface of the shuttle's skin.
NASA engineers spent several days analyzing the damage before deciding not to send a repair team to squirt a caulk-like substance into the divot. Officials feared the repair could make the situation worse by changing the shape of the cavity, which could concentrate heat in the damaged area instead of limiting it.
Although a detailed analysis of the damaged tiles will be done in coming days, they fared better than expected in the 2,300-degree frictional heat of re-entry into the atmosphere, NASA said. There was some additional erosion around the tiles but no indication the shuttle body was damaged.
Kelly said that dings and divots are just "part of the process of flying the space shuttle." He said he agreed with the decision not to fix the damage and did not worry during re-entry.
Endeavour's crew installed a truss section to the station's backbone, along with a storage bin and a gyroscope to replace one that had failed. Four gyroscopes keep the station properly aligned.
With the addition of the truss section, the space station is 60 percent complete. "Little bit by little bit, we get the station built," Griffin said. "It's an awesome accomplishment."
The mission was planned for 14 days, but the approach of Hurricane Dean toward NASA's ground-control center in Houston caused mission managers to bring the crew home a day early.
