Edward Lu, 39, and Russian cosmonaut Yury Malenchenko, 41, will lift off from the Baikonur Cosmodrome in Kazakhstan for a six-month mission on the International Space Station (ISS) aboard a Soyuz craft.

Lu, a Chinese-American who has carried out two previous space flights, spent two months training at the Star City astronaut centre outside Moscow before arriving at this Soviet-era space launch pad in the barren Kazakh steppe last Sunday.

The flight will blast off at 5:54 GMT and the crew will dock at the ISS two days later at 5:56 GMT Monday.

Lu said last week that he would be thinking of his fellow Americans who died in the February 1 disaster, but insisted this should not set back the exploration of space.

"I think the flight does have extra meaning because of that, because of the fact that our close friends did perish just two months ago," Lu told reporters.

"We of course will be thinking about them when we are up there, but that doesn't mean that we should stop what we are doing," he said. "If you stop at the first setback, you won't get anywhere."

The current ISS crew, US cosmonauts Kenneth Bowersox, Donald Pettit and Russian astronaut Nikolai Budarin, who heard in horror about the fiery death of their colleagues on the shuttle, will themselves soon make the journey back to Earth.

The crew, who had to stay on at the station longer than planned, will re-enter the atmosphere on May 4 in a Soyuz craft currently docked to the ISS, landing in Kazakhstan to complete their more than five-month mission.

NASA grounded the remaining three space shuttles after the accident and has had had to turn to cash-strapped Russia to transport crew and supplies up to the orbiting space station.

Although Russian Soyuz technology is more than 35 years old, the craft has an excellent safety record, with only two crashes involving Soyuz manned space missions.

On April 24, 1967, the first Soyuz to be launched on a test flight exploded on its return to Earth, killing the cosmonaut on board.

Then on June 30, 1971, three Russian cosmonauts died as their Soyuz vessel re-entered the atmosphere.

"It's the most reliable spacecraft in the world in terms of its safety record. They've been flying Soyuz vehicles for 36 years but they've only had two accident," Rob Navias, a NASA spokesman, told AFP.

Denied financial assistance from Washington for its space program under US law because of Russian military cooperation with Iran, Moscow has budgeted an additional 1.2 billion rubles (38 million dollars, 35 million euros) over the next six months.

But thinly-stretched resources mean that to cut down on spending, future missions to the ISS will comprise two, instead of three, astronauts.

This will largely limit the next crew's activities to maintenance of the space station, meaning that no more spacewalks are likely to take place this year.

"We will be busy maintaining the station. That will take the bulk of our time," said Malenchenko.

Some minor scientific tests will be carried out, including a series of experiments to reduce bone loss in space.

"This is extremely important for future expeditions to Mars," said the Russian astronaut.

Forty astronauts were to have visited the ISS in 2003 onboard two Russian Soyuz rockets and five US shuttles while three Russian Progress cargo craft were to deliver supplies and nudge the station into a higher orbit.

But the deputy director of the Star City astronaut training center, Andrei Maibarodi, said that despite the extra Russian government funding, Russia did not have the capacity to send more astronauts to the ISS.

"We are unlikely to increase production of transport craft, we can only expect more cargo craft to be produced," he said.

After the Columbia disaster, Moscow took on an obligation to fly two manned Soyuz flights and five unmanned Progress cargo craft to the ISS this year. Water and food supplies were mainly delivered by US shuttles.

Jim Newman, NASA's chief representative in Russia, told reporters in Moscow it would take at least a year before the United States could resume the shuttle flight programme.

SPACE.WIRE