CAPE CANAVERAL, Florida (Reuters) - Shuttle Endeavour astronauts floated aboard the International Space Station on Friday, swelling its crew to a record 13 and marking the start of an ambitious 11-day construction mission.
After parking Endeavour and checking for leaks, the seven shuttle astronauts clambered through hatches shortly before 4 p.m. EDT (2000 GMT) and were embraced by station commander Gennady Padalka and his five crewmates.
It was the first time representatives from all five of the primary station partners -- the United States, Russia, Europe, Japan and Canada -- were together in orbit.
“We’re extremely happy to be here,” said Endeavour commander Mark Polansky. “Thirteen is a pretty big number.”
The crew’s main job is to install the last part of Japan’s research laboratory, an open platform to house science experiments outside the station. During five spacewalks, the first scheduled for Saturday, they also plan to replace batteries in the station’s solar power system and position spare parts to prepare the orbital outpost for operations after the shuttles are retired next year.
As the astronauts gathered in orbit, NASA began looking at its remaining shuttle fuel tanks in hopes of learning why Endeavour’s tank shed insulating foam during its climb to orbit on Wednesday.
The agency said the problem, which has been a safety issue since space shuttle Columbia broke up on re-entry in 2003, killing all seven astronauts aboard, needs to be resolved before the next shuttle is cleared for launch.
NASA has seven flights remaining to complete construction of the space station.
“We’ve got a team together to start working the issue,” said NASA spokesman Steve Roy of the Marshall Space Flight Center in Huntsville, Alabama, which oversees shuttle external fuel tank production.
After a two-day voyage, the shuttle reached the station at 1:47 p.m. EDT (1747 GMT) in a rendezvous 220 miles over the Gulf of Carpentaria, north of Australia.
Before slipping the shuttle into its berthing port, Polansky backflipped his ship so astronauts aboard the station could photograph the black heat-resistant ceramic tiles on Endeavour’s belly. The tiles are part of the heat shield needed to protect the shuttle and its crew during the fiery supersonic glide back to Earth.
The photographs, which will be transmitted to engineers on the ground for analysis, have been part of safety inspections since the Columbia accident.
Video and photographs taken during the shuttle’s launch showed about a dozen pieces of debris flying off the tank, and although a few struck the orbiter, they are believed to have caused only cosmetic damage.
Some of the foam loss came from a part of the tank that had not previously been a problem and NASA said that made it a potentially more serious issue that must be dealt with before future shuttle flights.
Shuttle program manager John Shannon told Reuters the problem was likely due to some kind of processing oversight or change that left the foam improperly bonded to the tank’s metal skin.
He said he was optimistic the issue could be resolved in time to support the planned August 18 liftoff of shuttle Discovery.
Among the Endeavour crew’s first tasks is the transfer of astronaut Timothy Kopra to the station crew. He replaces Japan’s Koichi Wakata, who has been serving as a station flight engineer since March.
The shuttle is due back at the Kennedy Space Center in Florida on July 31.
Editing by Tom Brown and Peter Cooney