As Tim Peake blasted off from the Baikonur Cosmodrome in Kazakhstan, becoming the sixth person from Britain to go into space, David Cameron tweeted a photo of himself watching the launch:
Within moments, the internet responded with suggestions of what the prime minister may have been watching. Here are some of the printable ones:
Peake launched into space at 11.30am on 15 December alongside Tim Kopra and Yuri Malenchenko as the Principia mission took its first steps towards the International Space Station (ISS). The 43-year-old Briton is the first European Space Agency astronaut to complete a mission on the ISS.
Doug Millar, senior curator of the Science Museum, said: "To have the first British astronaut going up to the International Space Station is hugely important, we've finally arrived at the top table."
Peake is said to have listened to Queen's Don't Stop Me Now, U2's Beautiful Day and Coldplay's A Sky Full Of Stars as he made his final checks before the Kazakhstan-built Soyuz rocket launched into space.