British Major Tim Peake , American astronaut Timothy Kopra and Russian cosmonaut Yuri Malenchenko, will climb into a tiny capsule tomorrow and wait for the huge engines of a Soyuz rocket beneath them to ignite.
People for hundreds of miles around will watch a flaming dot rise from near the town of Baikonur in Kazakhstan.
For Peake, this nail-biting moment is the beginning of a 173-day orbital odyssey aboard the International Space Station, and the culmination of years of painstaking training to become Britain's first "official" astronaut.
It will also see him join an exclusive club of more than 200 men and women who have begun their journeys into space from the same launch pad since Yuri Gagarin blasted off in 1961.