The billionaire founder of the Cirque du Soleil show was on Wednesday to blast off on a Russian rocket on a mission to bring humour into the ultra-serious world of space flight.

Guy Laliberte (50), a Canadian citizen, will visit the International Space Station (ISS) for a two week mission as the latest "space tourist" to spend millions from a personal fortune on going into orbit.

He will blast off from Russia's Baikonur cosmodrome, located in neighbouring Kazakhstan, at 7.14am GMT alongside a professional Russian cosmonaut and US astronaut.

"All the work on the launch pad has been carried out according to plan. I wish you success and thank you for the good preparation," said the head of the Russian space agency Roskosmos, Anatoly Perminov, as he bade farewell.

The crew boarded the Soyuz space craft under a gleaming blue sky several hours ahead of the launch, waving at cheering onlookers.

Laliberte, a former fire-eater and stiltwalker, is taking nine red clown noses into space ? one for each member of the ISS crew ? and has said he will not abandon his lighter side once the mission starts.

"I am going with my sense of humour. Even in serious things you need to leave a place for humour," he said ahead of the mission.

But on a more serious note, he also intends to use his trip to raise awareness of water problems worldwide.

The circus founder, the seventh person to go into space as a tourist, could be the last for some time as seats will be limited aboard the Soyuz craft once NASA takes its shuttles out of service from 2010.

He is travelling with US astronaut Jeffrey Williams, a veteran of two space flights and Russia's Maxim Surayev, a member of Russia's space team for a decade who will also be undertaking his maiden flight.

When they dock with the ISS, the station's crew will increase to nine before Laliberte returns to Earth in a fortnight with Russian cosmonaut Gennady Padalka and Michael Barrett of the United States.

Laliberte has not disclosed how much he paid for the trip, although the last space tourist, US software pioneer Charles Simonyi, paid $35-million (?28-million) for the privilege.