Tim Peake: How might his mission affect his world view?
Fewer than 600 people have seen Earth from space - the rest of us will have to make do with incredible time-lapse footage such as this from the European Space Agency.
However, flown astronauts say the view has had a huge impact on them, making them think about issues such as sustainability.
Former astronaut Michael Lopez-Alegria explains the "Overview Effect" that British spaceman Tim Peake can expect on his forthcoming mission.
Video produced by Sara Barman.