Russia on Thursday launched into space a trio of Russian, Japanese and US astronauts carrying an unlit Olympic torch that will for the first time be taken on a spacewalk to mark the 2014 Winter Games in Sochi.

The Soyuz-FG rocket and Soyuz-TMA capsule, emblazoned with the symbols of the Sochi Games and the Olympic rings, blasted off from Russia's Baikonur cosmodrome in Kazakhstan for the International Space Station (ISS) at 8:14 am Moscow time (0414 GMT).

The Soyuz-TMA capsule carrying NASA astronaut Rick Mastracchio, Russia's Mikhail Tyurin and Japan's Koichi Wakata then docked with the ISS slightly ahead of schedule after four orbits of the Earth just over six hours later, the Russian space agency Roscomos said.

"The Soyuz TMA-11M manned capsule docked successfully with the ISS at 14:27 Moscow time (10:27 GMT)," Roscosmos said. The astronauts are set to open their hatch and go through into the ISS at around 4:40 pm Moscow time (12:40 GMT).

In an unprecedented move, two Russian cosmonauts who are already on board the ISS are set to take the torch on a space walk from 1430 GMT on Saturday aimed at promoting the Sochi Games.

Russian officials have made it clear that the torch will remain unlit at all times for safety reasons.

The cosmonauts will hold a photo session in open space with the torch, which will be tethered with a special strap, and then carry out essential work. The torch will spend more than 5 hours outside the ISS.

"We all understand and have a responsible attitude because the torch is a symbol and therefore it needs to be treated with respect and maybe even reverence," cosmonaut Tyurin said ahead of the launch in televised comments.

The Olympic torch was carried into space ahead of the 1996 and 2000 Olympics in Atlanta and Sydney but has never before been taken on a spacewalk.

However, Russia's efforts to promote the Sochi Games as a symbol of its post-Soviet transformation have been tarnished by rows over a law seen as anti-gay as well as allegations of corruption in the vast construction needed for the event. Polar bear Sochi talisman
On the ISS, the newly arrived astronauts will join six incumbent crew, station commander Fyodor Yurchikhin of Russia and flight engineers Karen Nyberg of NASA, Italy's Luca Parmitano, Russian Oleg Kotov, NASA's Mike Hopkins and Russian Sergei Ryazansky.

After a brief stay on the ISS, the torch will then be taken back to Earth by the three astronauts now finishing their five-and-a-half-month mission on the ISS. They are due to touch down in Kazakhstan on Monday at 0250 GMT.

The same torch will later be used to light the Olympic flame at the Fisht stadium in Sochi for the opening ceremony of the Games on February 7.

In a spectacular torch relay, Russia last month took a lit Olympic torch to the North Pole on a nuclear-powered icebreaker.

The high-profile Olympics mission comes as Russia seeks to prove that its mostly Soviet-designed systems are reliable enough to continue humans' conquest of space.

The 2011 retirement of the US Space Shuttle programme made the Soyuz -- whose basic principles are little changed since the first manned spaceflight by Yuri Gagarin in 1961 -- the world's last remaining manned link with the ISS.

But Russia has been recently blighted by a string of space failures that include the July 2 explosion shortly after take-off from Baikonur of an unmanned Proton-M rocket.

In an apparent response to the problems, Russian Prime Minister Dmitry Medvedev on October 10 fired the head of the state space agency Roscomos, Vladimir Popovkin, after just two-and-a-half years in the job.

Oleg Ostapenko, previously deputy defence minister, was appointed the new Roscosmos chief.