Endeavour blasts off in sixth attempt

The belated liftoff of mission STS-127 from Kennedy Space Center is NASA's sixth attempt to get Endeavour off the ground.

After five previous delays - two due to a leak in the shuttle’s hydrogen gas venting system and three thwarted due to bad weather, the seven astronauts began their journey to deliver the third and final segment of the Japanese Kibo science laboratory.

After getting clearance for liftoff of Endeavour from meteorologists and technical directors, Pete Nickolenko, the launch director, told the crew over the radio, "The vehicle's ready, our support teams are definitely ready and the weather is finally cooperating, so it's now time to fly."

The falling debris
As the Endeavour blasted, a cloud of debris fell from the shuttle’s external tank. Several pieces of debris hit the shuttle's heat shield, but it was not yet certain whether the fragile heat shield suffered any significant impact damage.

Although debris is not unexpected during launch, the number of events seen during the shuttle’s ascent was unusual. The video footage revealed at least 15 debris events between liftoff and two minutes and 20 seconds into flight.

The initial examination showed small streaks on the shuttle where external coating of the orbiter's tiles was scuffed.

Mike Moses the launch integration manager stated the light scuffs can be repaired with a black shoe polish-like material, while deeper ones can be handled with a putty-like filler.

“These looked like individual small hits that just took the top coating off,” Moses said

"The bottom line is, we saw some stuff, some of it doesn't concern us, some of it you really just can't speculate on right now," Moses said. "We have the tools and processes to go clear this vehicle for entry. You'll know as we know what we find when we do (the inspections). No real worries there, we've just got to wait and see what happens."

However, engineers will need several days to evaluate launch and on-orbit imagery to make sure there are no problems.

The mission
If all goes well, Mark Polansky, Endeavour's shuttle commander, and his crew are expected to dock with the International Space Station Friday afternoon.

The primary goal of the crew on the 16-day mission is to install the Japanese Kibo lab module, swap aging solar-array batteries and perform other maintenance tasks, delivery of spare parts and components for the orbiting space station.

The crew will conduct a five spacewalks over two weeks. One of the tasks involves hooking up the new porch outside the Kibo lab for experiments that require exposure to the vacuum of space.

While the shuttle is docked to the station, there will be 13 astronauts working in space at one time - the highest number in the station's history.