Astronauts aboard the space shuttle Discovery will examine their ship's heat shield today for signs of damage as they head towards a rendezvous with the International Space Station on a critical mission for the US shuttle program.
Discovery was launched successfully from Florida last night on just the second mission since the destruction of shuttle Columbia in 2003. Another accident or serious problem could ground the shuttle fleet permanently.
NASA officials said the shuttle's troublesome external fuel tank, which triggered the Columbia accident, shed some small pieces of insulating foam during Discovery's launch. But the losses were expected and were no immediate cause for concern.
"At the end of the day, I'm very pleased with the performance of the tank," shuttle program manager Wayne Hale said. "This is a great improvement over where we were."
NASA managers had warned for weeks that the shuttle's fuel tank would continue to shed debris, but had said no pieces would be large enough to damage the shuttle in case of impact.
Columbia was destroyed when a 1.67-pound (756-gram) chunk of foam broke off from its fuel tank and smashed into the ship's left wing. The damage was undetected until after Columbia broke apart 16 days later as it flew back into the atmosphere from space, killing all seven astronauts aboard.
NASA spent $1.3 billion over the last three years to fix the fuel tank and make safety upgrades to the shuttle. The agency needs a successful mission to resume construction of the half-built, $100 billion space station, which has been on hold since the Columbia accident.
The astronauts will use a sensor-laden boom to scan Discovery's wings and nose-cap, areas particularly vulnerable to damage. The crew will photograph and videotape the heat-resistant tiles on the shuttle's belly as Discovery approaches the space station for docking tomorrow.