Nasa set to resume space station construction

CAPE CANAVERAL, Florida - Nasa is set to launch the shuttle Atlantis on Sunday to kick off a four-year building marathon aimed at completing construction of the International Space Station.

The US space agency has launched just two shuttle missions since the 2003 Columbia disaster, both to test safety improvements.

Nasa hopes to launch and assemble a backlog of station components before the space shuttle fleet is retired in 2010.

The US shuttles are the only spacecraft capable of carrying some of the larger components of the space station which were designed to fit into its payload bay.

Shuttle Atlantis and six astronauts are targeted for launch at 4.30pm EDT (2030 GMT - 0830 NZT) from the Kennedy Space Centre in Florida.

Aboard Atlantis is the second of four sets of solar arrays that will power three station science laboratories, two living chambers and other systems.

More than a dozen truss segments and modules, designed to fly only on space shuttles, await rides to orbit.

Nasa has curtailed US research programmes aboard the space station to focus instead on finishing the multinational complex. Agency administrator Mike Griffin said the decision to build first and use later was a no-brainer.

"I live in a Nasa world that is defined by the loss of Columbia," he said last week.

The shuttle's breakup over Texas on February 1, 2003, killed seven astronauts, destroyed a US$2 billion ($3.17 billion) spaceship and scuttled Nasa's plan to fly the shuttles through 2015 and beyond.

The accident changed the United States' plans for human spaceflight, recasting beyond the low-Earth confines of the shuttle and space station programmes to focus on further exploration of the moon and eventually Mars.

To comply with its new mandate, Nasa cancelled research programmes on the station that did not directly support efforts to return to the moon. Then, as budget overruns blossomed, even those programmes were cut back.

There will still be basic microgravity research staged aboard the station, just not any funded by Nasa.

"The partners have not slowed down," Canadian Space Agency astronaut Steve MacLean said in an interview.

"Europe, Canada, Japan are still planning their original scientific plans and the strategic thinking is still the same," he said.

"I think those goals are huge in terms of the impact they may have down the line, in materials science and especially in medical areas."

Dieter Isakeit, director of the European Space Agency's research and development centre in the Netherlands, welcomed the resumption of construction.

"We have confidence again," he said.

"Things are moving forward."

At the request of its partners, Nasa juggled the station assembly sequence to get the new labs in orbit as quickly as possible.

Europe's Columbus module is due to fly next year, followed by the first of three missions to launch Japan's elaborate Kibo laboratory and related equipment.

MacLean, who will be flying aboard Atlantis, holds out hope that the United States will rejoin its partners in key science programmes aboard the station.

"I think once we have it complete and the managers see what's possible, they can be re-convinced," he said.

- REUTERS