Fifty years ago this week, Ed White experienced a 23-minute period that would create Nasa history. He became the first American to carry out a space walk, when he climbed out of the Gemini 4 spacecraft on 3 June 1965, and floated dozens of miles above the Earth.
Leonov's 12-minute spacewalk very nearly failed because of problems with his suit (Credit: RIA Novosti/Science Photo Library)
The images he took, hovering serenely in front of our cloud-flecked planet, became some of the most enduring of the golden age of the Space Race.
White’s space walk was an American first, but he was following in the trail of an even greater pioneer. Alexei Leonov, one of a group of 20 Soviet pilots selected to be become the first Soviet cosmonauts, carried out the first space walk in human history a few months earlier, on 18 March 1965.
As our colleagues in BBC News wrote in this special feature last year, Leonov’s historic mission was very nearly a disaster; during his 12 minutes outside the Voskhod 2 capsule, connected to the vessel by a tether some 17ft (5.3m) long, Leonov’s space suit inflated in the vacuum of space and he was unable to enter the capsule without bleeding some of the pressure from his suit. The procedure could have caused his blood to boil and killed him; but thankfully Leonov’s decision worked.
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Voskhod 2 made it back to Earth with Leonov and his colleague Pavel Belyayev, coming to rest in the dense taiga forests north of the Soviet city of Perm, near the Ural mountains. The pair had to endure temperatures of -5C (23F) while waiting to be rescued.
The experience took a tough physical toll on the physically fit Leonov. Launching a forthcoming cosmonaut exhibition at the Science Museum in London last month, he said that prior to his spacewalk he would normally need to run in his woollen shirt for a couple of miles before he saw his first bead of sweat; Leonov had spent his brief spacewalk and difficult re-entry sloshing about in his own sweat. The enormous exertion made him lose 6kg in weight.
Leonov appeared in London last month to announce a new exhibition on the history of Soviet space exploration at the Science Museum (Credit: Stephen Dowling)
Leonov’s and White’s momentous space walks paved the way for ever-more ambitious space walks that have culminated in today’s routine Extra-Vehicular Activities (EVAs), with today’s astronauts and cosmonauts regularly spending hours outside of the International Space Station (ISS). Thanks to Leonov and White’s first, brave walks, many others have followed.