The astronauts of space shuttle Endeavour spent Thursday searching for damage to their ship after pieces of ice -- or perhaps insulating foam -- came off the shuttle's orange fuel tank during Wednesday's launch. and struck the shuttle. NASA says so far, so good.
"There is nothing we have seen on the orbiter so far that gives us any concern," said John Shannon, the Space Shuttle Program Manager, late in the day.
But inspection of the ship's exterior will continue.
Debris is not unusual during a launch -- usually one or two pieces are spotted -- but engineers said the amount of debris seen during this launch was remarkable. Video from a camera on the fuel tank showed at least a dozen instances of debris falling toward the shuttle as Endeavour rocketed away from the launch pad.
They've been down this path before. Endeavour landed in fine shape at the end of a flight in 2007, after mission managers spent much of the mission debating whether to do anything about a damaged tile near the shuttle's tail.
But NASA managers were shaken to the core by the Columbia disaster in 2003, when a suitcase-sized piece of foam broke off the fuel tank, broke a hole in the ship's wing – and was dismissed as routine. Super-hot gases, coming through that hole like the flame from a blowtorch on re -entry, doomed Columbia and its seven astronauts.
Ever since, NASA has had laborious procedures to check for similar damage, and that is what Endeavour's seven crewmembers began today. They used a camera, extended from the end of the shuttle's robot arm, to examine the shuttle's underside inch by inch – and they will repeat the whole thing before landing.
When they dock with the International Space Station, as currently scheduled on Friday afternoon, they will do a slow back-flip so the station's astronauts can also photograph the ship with using telephoto lenses.
They carry several repair kits, so that if there is a potentially-dangerous hole in a tile, spacewalking astronauts can fill it with heat-resistant putty, or cover it with a metal plate.
In a worst-case scenario, they can take refuge on the space station until a second shuttle comes to get them, and ditch the damaged Endeavour in the Pacific.
Or they can do nothing. Several flights have landed with damaged tiles before, and -- until the Columbia accident -- engineers thought little of it.
Endeavour's astronauts were told about the debris shortly after they reached orbit Wednesday evening.
"At about 107 seconds during ascent, we did see some debris events," said Capcom Alan Poindexter. "Impacts were observed on the underside of the forward part of the right wing, similar to, but less severe than damage on previous flights."
"Thanks for the info," said Mark Polansky, the commander. "I'm sure we'll get a good chance for all of us to get a good look at all that."
Flying with him are Douglas Hurley, the pilot; Julie Payette of the Canadian Space Agency; and spacewalkers David Wolf, Christopher Cassidy, Thomas Marshburn and Timothy Kopra.
They originally expected to be launched in June, but were repeatedly delayed, first by a hydrogen leak, then by Florida thunderstorms.
Polansky has a Twitter account, and sent his first message: "This was so worth the wait. What a spectacular launch. Earth is breathtaking. Time for bed now."