Yuri Gagarin

His 108-minute journey into space made him the first man to orbit the Earth and one of the 20th century's greatest heroes but Yuri Gagarin was almost undone by a wonky door and an overweight spacesuit...

Source: http://www.smh.com.au/world/late-glitches-almost-aborted-first-space-flight-20110407-1d699.html