Three new crew members blast off Thursday for the International Space Station (ISS) on a Russian rocket, taking with them the precious cargo of an Olympic torch for the 2014 Winter Games in the Black Sea resort of Sochi.
In an unprecedented move, the Olympic torch will on Saturday be taken out into open space on a spacewalk by two Russian cosmonauts to mark Russia's hosting of the Games in February.
The Soyuz-FG rocket and Soyuz-TMA capsule, emblazoned with the symbols of the Sochi Games and the Olympic rings, have already been installed on the lauch pad of Russia's Baikonur cosmodrome in Kazakhstan.
In a sign of the launch's importance, it will be broadcast live on a big screen to thousands of people watching in New York's Times Square, according to NASA.
The Soyuz will at 0414 GMT on Thursday take Mikhail Tyurin of Russia, Japan's Koichi Wakata and NASA astronaut Rick Mastracchio on the six-hour trip to the ISS.
There they will join six incumbent crew on board, the first time since October 2009 that nine people have served together aboard the space station without the presence of the now retired US space shuttle.
On board they will find 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.
Kotov and Ryazansky will from 1430 GMT on Saturday carry the Olympic torch on a spacewalk outside the station. Russian officials have made clear that the torch will at no point be lit, for safety reasons.
In a crammed few days for the ISS, Yurchikhin, Nyberg and Parmitano will then end their five-and-a-half-month mission and return to Earth, touching down in Kazakhstan at 0250 on Monday.
Joining them on the return after its brief spell in space will be the torch, which will later be used to light the Olympic flame at the Fisht stadium in Sochi for the opening ceremony on February 7.
The return to Earth will draw the curtain on a dramatic mission for European Space Agency (ESA) astronaut Parmitano, who suffered a scare during a spacewalk on July 16 when his helmet began to fill with an unidentified liquid.
He described being blinded and suffocating as he struggled to make his way back to the airlock.
NASA said a part of his American spacesuit suspected of causing a water leak during the spacewalk has been carefully packed for inspection by engineers on the ground.
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.