The U.S. space shuttle Atlantis is on its way to the international space station after a four-day delay because of a fuel leak. Shuttle crewmembers will continue space station construction after they arrive Wednesday.
High winds at the Florida launch site subsided enough for the shuttle to take off with a crew of seven and a 13-meter, 13-ton girder that four of the astronauts will connect to the station during four spacewalks.
The girder is the centerpiece of a 10-part truss that will eventually stretch 100 meters across the U.S. laboratory Destiny. Space station program manager Tommy Holloway says they will make up the structure that will house life support utilities for future research laboratories. "They provide the framework for the power and the cooling, external cooling, for the international space station, a very important series in the critical path of eventually completing the building of the international space station," he said.
The shuttle's liftoff had been postponed four days to give technicians time to weld a cracked fuel supply pipe. Hydrogen had leaked from it last Thursday as it was being loaded into Atlantis.
Then a last minute problem with computers that track the health of the shuttle's systems threatened to delay the launch yet another day. But flight director Mike Leinbach says engineers reloaded the computer software with just 11 seconds to spare before the end of the tight five-minute launch opportunity.
"We were getting down to the wire [close to the deadline], I have to admit. Had we gone 12 more seconds, we would have been scrubbed [shut down] for the day," Mr.Leinbach said.
The U.S. space agency NASA imposed extremely tight security on this launch, as it has on others since the September terrorist attacks against New York and Washington. The astronauts' pre-flight activities were not televised and in a new stricture, the precise launch time was not officially announced until 24 hours before liftoff. Military aircraft and boats patrolled the no-fly and no-sail zones around the coastal launch site.
Hours before the shuttle's liftoff, Air Force jets intercepted a small private aircraft that had wandered into the zone and forced it to land at a nearby airport.
NASA chief Sean O'Keefe says the inconvenience is worth the stepped-up security. "We ought to always be diligent about what we're doing to make this less of an attractive target on the part of anybody who would seek to gain our attention by doing something dramatic," he said.
The Atlantis team will be the first visitors that the three U.S. Russian space station crewmembers have had since they arrived at the outpost in December.