A Russian Soyuz spacecraft with three astronauts on board blasted off from Kazakhstan yesterday in a mission that will increase the International Space Station crew to six for the first time.

Belgian Frank de Winne, Canadian Robert Thirsk and Russian Roman Romanenko lifted off from Russia's Baikonur cosmodrome in Kazakhstan as planned, an official at Mission Control outside Moscow said.

The spacecraft safely reached its targeted orbit of about 200-242 kilometres above the earth.

"The space ship Soyuz TMA-15 has now safely entered the designated orbit," the official announced to applause at Mission Control.

The Soyuz TMA-15 spaceship is scheduled to dock with the ISS tomorrow. The incoming crew will join Russian Gennady Padalka, US astronaut Michael Barratt and Japan's Koichi Wakata.