The Russian Soyuz TMA-2 rocket, carrying Russian flight commander Yury Malenchenko and US flight engineer Edward Lu, lifted off at 0354 GMT and is due to dock with the International Space Station early Monday.

All US space missions have been grounded since the Columbia shuttle disintegrated and burnt up on entry, killing all seven crew members, on February 1, making Russia the only link with the 16-nation orbital station.

The Soyuz rocket tore up into the sky in a burst of orange giving off clouds of smoke.

Clapping erupted but Lu's brother Rick and fiancee Christine waited tensely as they watched the US cosmonaut on a TV screen as a countdown began toward orbit.

They looked anxiously on as the screen went fuzzy at one point and the image went off.

But nearly nine minutes into the flight, there were smiles of relief and loud clapping as it was announced that the craft had successfully reached orbit. "Oh, boy!" exclaimed Rick.

"It's ecstatic," said Christine. "I'm so relieved after that last stage. I was holding my breath. It's my first launch. The relief is overwhelming."

"We're so happy for him. He was so excited about the launch," said Rick. Lu's mother watched the lift-off from mission control in Moscow.

Some three hours into the flight, the crew prepared for the first engine-firing to correct their orbit and reported that all was fine onboard, NASA officials in Baikonur said after contact with Russian ground control.

Fred Gregory, deputy NASA administrator, who was present along with other top US and Russian space officials, including Russian Space Agency chief Yuri Koptev, paid tribute to the Russians.

"I was very impressed with the people, the professionalism and the successful launch. It's my first time on Baiknour," he said.

"It has been quite an achievement with the Russians and Americans, they have done a magnificent job.

"This was a very, very important mission, that we have people going up. It shows the commitment of partnership to a continued sustained presence on the station," added Gregory.

Since NASA grounded the remaining three space shuttles after the Columbia accident, Russia's Soyuz manned craft and Progress cargo vessels have been the only means to transport crew and supplies up to the ISS.

Because of the problem of getting supplies to the space station, which were mainly delivered by shuttles, future missions will comprise two, instead of three, astronauts.

Lu, 39, and Malenchenko, 41, will be eagerly awaited by the current ISS crew, US astronauts Kenneth Bowersox, Donald Pettit and Russian cosmonaut Nikolai Budarin, who were to return in March but had to extend their mission after the Columbia tragedy.

After a week to hand over control of the space station, the outgoing crew will make the journey back to Earth on May 4 in a Soyuz docked at the ISS. Lu and Malenchenko will be replaced by another two-man crew in October.

At the launch-pad in the barren Central Asian steppe, the two astronauts had climbed aboard the Soyuz craft some two-and-a-half hours before lift-off, hoisted to the hatch at the top on a hydraulic elevator.

Under an old Soviet-era tradition that is supposed to bring luck, the astronauts urinated on the wheel of the bus which took them to the launch site.

As dawn broke and a pale orange glow filled the sky, they headed off for their flight after a 45-minute meeting of a state commission that gave the final go-ahead.

The astronauts, wearing white space suits, underwent last-minute tests as Russian space technicians pressurized their suits to test them for leaks.

The officials told the two-man crew that Russian President Vladimir Putin had telephoned to wish them a safe flight.

Lu and Malenchenko earlier checked out of the Cosmonaut Hotel just before 3 am to the strains of the Soviet song "Earth through the porthole," a long-standing tradition in Baikonur.

A black-robed Orthodox priest holding a golden cross walked around their bus sprinkling it with holy water, on the eve of Easter in the Orthodox calendar.

SPACE.WIRE