British astronaut Tim Peake will embark on his landmark flight to the International Space Station (ISS) today, after six years of preparation and thousands of hours of intensive training. The former British Army Air Corps officer will blast off at 11.03am GMT from Site 1 at Baikonur in Kazakhastan on a Russian Soyuz rocket, with Russian Yuri Malenchenko and American Tim Kopra.
Ahead of his expedition to the ISS, here are eight things you did not know about Peake and his mission.
The UK astronaut beat over 8,000 other applicants for one of the six places on the ESA's new astronaut training programme, pipping the other hopefuls to the post in a series of gruelling academic tests, fitness assessments and interviews. If successful, he will become the first Briton to fly to space without a private contract or American citizenship.
Peake has already spoken about his dreams of heading to the Red Planet after he returns from the ISS. "I would like to go to Mars. I think it's fascinating; it's quite closely related to Earth in being one of the small, rocky planets that probably once had an atmosphere and once had oceans on it," he told a student in a Q&A session.
One of the most difficult parts of the training has been learning Russian, a notoriously tricky language to master. It is needed to operate the Soyuz rocket and the Russian parts of the ISS. He told the BBC that learning Russian has been "a struggle".
The astronauts have taken a lift to the top of the Soyuz rocket and will be strapped in as part of the final preparations before the launch. The journey to the ISS will take six hours, with the Soyuz orbiting the planet four times before their arrival. The ISS is around 400km (250 miles) away from Earth, in what is called a "low orbit", and orbits our planet at a speed of 17,500mph.
The crew are placed in quarantine for two weeks before launch to ensure they do not get ill in space.
Peake's key role is to take part in experiments on the ISS that examine how new materials react in a weightless environment and the effects of living in space on the immune system. He will also have a portable gas mask to monitor molecules in his breath, which could help understand whether astronaut stations on a lunar base suffer from inhaling moon dust.
Peake will grow taller by as much as 3% while living in microgravity in space, but will return to his normal height when back on Earth. Studies have shown that when the spine is not exposed to the pull of Earth's gravity, the vertebra can expand and relax − allowing astronauts to gain height.
The commander on Peake's flight is Malenchenko – who has spent 641 days in space and became the first to marry in space in 2011, when he wedded his fiancée via radio link while on board the ISS.