Successful lift-off, now time to check shuttle damage

CAPE CANAVERAL - Astronauts aboard the space shuttle Discovery will examine their ship's heat shield today for signs of damage as they head toward a rendezvous with the International Space Station on a critical mission for the US programme.

Discovery was launched successfully from Florida yesterday on just the second mission since the destruction of shuttle Columbia in 2003. Another accident or serious problem could ground the 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 launch, but said there was no immediate cause for concern.

"I'm very pleased with the performance of the tank," shuttle programme manager Wayne Hale said.

"This is a great improvement over where we were."

Managers at Nasa had warned for weeks that the space shuttle's fuel tank would continue to shed debris despite improvements, but had said no pieces would be large enough to damage the shuttle in case of impact.

Columbia was destroyed when a 756g 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 re-entered the Earth's atmosphere, killing all aboard.

Nasa spent US$1.3 billion ($2.16 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, US$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 the heat-resistant tiles on the shuttle's belly as it approaches the space station for docking.

"We can detect very small damage indeed, down to about an eighth of an inch, I believe," Hale said.

Discovery's 12-day mission is meant to test the fuel tank repairs and deliver badly needed supplies and equipment to the space station. The astronauts will make two spacewalks.

One will test a new 15-metre extension to the shuttle's robot arm. Crews use the boom to inspect the ship for damage but Nasa wants to know if it could manoeuvre astronauts to inaccessible shuttle areas for repairs.

During the second spacewalk, Piers Sellers, a British-born climate scientist, and Michael Fossum, an American making his first spaceflight, will try to fix the International Space Station's mobile transporter.

The transporter, which travels on tracks on the outside of the space station, will be needed to install trusses and solar arrays on the space station. It has been broken since December.

IMPROVEMENTS FOR LATEST VOYAGE OF DISCOVERY

The astronauts

* Seven astronauts are on Discovery.

* European Space Agency astronaut Thomas Reiter is staying behind on the International Space Station for an expected 145-day mission.

* Commander Steven Lindsey is in charge of the five-man, two-woman crew.

* Also on board are: Pilot Mark Kelly, Flight engineer Lisa Nowak, Mission specialists Michael Fossum, Stephanie Wilson and Piers Sellers.

Space shuttle safety

* Since July 2005, areas of foam insulation weighing 16kg have been removed from Discovery for safety.

* Sensors have been added to check launch temperatures and stress.

* Heaters installed before Discovery flew in 2005 have been rewired.

* Discovery's launch was tracked by 55 land-based cameras, two surveillance aircraft and two radar systems to monitor debris loss.

Birds and other hazards

* A sound system has been fitted to scare away birds.

* More than 5000 cloth fillers between heat-resistant tiles on the shuttle's belly have been replaced.

* Two of the cloth strips slipped out during Discovery's last flight, requiring an unplanned spacewalk.

* Stronger windows have been fitted in the cabin. Discovery also has new tyres and improved landing gear.

- REUTERS