An international trio flying in a Russian capsule docked with the International Space Station on Wednesday with a busy schedule full of space walks and an encounter with a pioneering US cargo craft.

The six-month mission of Russian commander Fyodor Yurchikhin and his two flight engineers -- Karen Nyberg of NASA and Italian Luca Parmitano of the European Space Agency -- began once their craft sidled up to the orbiting lab six hours after blasting off from the Moscow-owned Baikonur space centre in Kazakhstan.

The Soyuz took a shortcut that slashed the travel time from the usual 48 hours thanks to a special orbit that catapaults the astronauts directly to their destination.

The abridged journey had rarely been tried in the past because it puts greater stress on the astronauts' bodies.

But one such trip was successfully completed earlier this year and Russia decided to repeat the experience with a view to making the six-hour journey the norm for future travel to the ISS.

"It was a pretty cool ride," Nyberg told her husband on Earth via video linkup after the trio had reached the ISS and floated on board the station.

Italy's Parmitano said he was especially excited because this was his first chance to experience space flight after years of gruelling training and practise.

"I feel the importance of performing well for all those people who have been working with me through all those years of training to get me to this point," he told reporters shortly before liftoff.

"Because of the training, you feel confident that you know you can do the job you've been trained for."

Past astronauts have made a habit of chronicling their experience with the help of social media websites such as Twitter -- winning tens of thousands of followers as a result.

Canada's Chris Hadfield took that social media experiment to new heights this month by releasing a link to his celestial performance of David Bowie's classic "Space Oddity".

The performance earned him nearly a million followers overnight.

Hadfield and his two fellow travellers returned safely to Earth on May 14. Left behind are Russian commander Pavel Vinogradov and his own two flight engineers -- Chris Cassidy of NASA and the cosmonaut Alexander Misurkin.

Both Parmitano and Nyberg have their own Twitter accounts that were filled with their emotions prior to liftoff.

Nyberg has already tweeted a link with a performance of "Twinkle Twinkle Little Star" for her son back home in the United States.

She tweeted Wednesday that she enjoyed a walk along the Avenue of Cosmonauts in Baikonur just hours before she was due to suit up and rumble up to the ISS.

The trio's six-month mission will include six space walks and a link-up with a pioneer US spacecraft called Cygnus.

The Cygnus is an unmanned resupply ship being designed by the private Orbital Sciences Corporation as part of a broader NASA effort to get commercial firms to fill the void left by the retired US space shuttle programme.

The craft that will dock to the ISS some time in June will arrive empty and not deliver any cargo as part of its very first launch.

The demo flight is due to be followed later in the year by an actual delivery of cargo using a more powerful upper-stage rocket.