Astronauts hoist cargo carrier onto space station

Astronauts attached a compartment full of newly delivered goods to the International Space Station on Thursday, enough to keep the lab complex running for years to come.

And for the second day in a row, huge reams of data streamed from the station down to Mission Control. The files contained laser images of space shuttle Discovery, hobbled by a broken antenna and unable to transmit or receive large packages of information.

Discovery's astronauts had to wait until they got to the space station Wednesday, before they could send down the wing and nose images they gathered Tuesday. NASA needs to review each image searching for any launch damage to the heat shields before committing the shuttle to re-entry on April 18.

It took considerably longer than expected to get all the files down. The files are huge considerably bigger than what usually flows from the space station. Flight controllers, with help from the astronauts, had to work around unexpected software features that slowed down the process, flight director Courtenay McMillan said.

Altogether, the shuttle images represent about 40 gigabytes of data.

There is no reason to suspect Discovery suffered serious damage during Monday's liftoff. But ever since the 2003 Columbia tragedy, a shuttle's wings and nose must be surveyed at least twice on every mission, using a 30-metre laser-tipped boom.

The second survey normally occurs right after undocking. But because of the antenna failure, the inspection will be conducted while Discovery is still docked to the space station, to take advantage of the space station's relay system.

McMillan said it's too soon to say whether Discovery will have to spend an extra day at the orbiting outpost. Another option would be to cut out some originally planned work in order to squeeze in the survey, and have the shuttle leave on time on April 16.

"Everything's on the table at this point," McMillan said.

Three spacewalks planned

Three spacewalks are planned over the coming days to replace a depleted ammonia tank that is part of the space station's cooling system. The first will take place Friday.

Discovery's main payload is the 13-tonne, six-metre cargo carrier that took up much of the payload bay. The astronauts used a robot arm to hoist it up onto the space station.

About half of that mass represents science experiments and supplies, as well as a new bedroom and freezer. The sleeping compartment may be turned into a powder room, where space station residents can take sponge baths and clean up.

Right now, when towels are dampened with water from drink bags, drops sometimes float away and can get into electronic equipment. The idea is to confine the baths to an enclosed space.

The Italian-built carrier named Leonardo after the Renaissance painter and inventor will return to Earth filled with trash and old equipment. Then its exterior will be beefed up and the compartment will be flown back to the space station in September on the last shuttle flight. It will remain at the station permanently, providing extra storage.

NASA intends to operate the space station until 2020.