In 1965, tethered to a spaceship by a 4.8m (16ft) cable, the Russian floated above Earth for 12 minutes but then, in the vacuum of outer space, his spacesuit began to balloon out of shape and its fabric began to stiffen dangerously.

His hands slipped out of his gloves, his feet came out of his boots, and Leonov could no longer get through his spaceship's airlock. Even worse, the craft was hurtling towards Earth's shadow. In five minutes, the cosmonaut realised he would be plunged into total darkness and a freezing temperature.

He managed to release some of the oxygen from his spacesuit and was barely able to squeeze himself back into the capsule headfirst before contorting his body 180 degrees in order to close the spacecraft's hatch.

On re-entry he and his pilot Pavel Belyayev crash-landed in a forest in the Ural mountains and waited three days to be rescued.

A decade later, Leonov was one of two Soviet cosmonauts involved in the first docking of US and Soviet spaceships - the Apollo 18 and Soyuz 19 - during a period of detente between the two countries.