"A sailor must be able to swim in the sea. Likewise, a cosmonaut must be able to swim in outer space." With those words, the head of the Soviet space program, Sergei Korolev, initiated the crew of the first spacewalk mission. On March 18, 1965, cosmonauts Alexei Leonov and Pavel Belyayev lifted off in Voskhod (Sunrise) 2, from which Leonov would exit to become the first person in history to step into the vacuum of space.

It would be nice to say that half a century later spacewalks are routine, but, if anything, the opposite is the case. Though astronauts from many countries have worked outside of their spacecraft, built space stations, and repaired satellites, getting into a spacesuit and stepping into an airlock is still a newsworthy event and one that's as complex and dangerous as a mixed-gas deep diving operation.

Fifty years ago, things were a bit simpler – and a lot more dangerous. When Leonov stepped out for history's first spacewalk, it was in the context of the Space Race. This was more than just a contest to see whether the United States or the Soviet Union could put the first man on the Moon. It was a major propaganda battle costing as much as a small war combined with a competition to, depending on your point of view, gain or deny the other side mastery of space.

It was also a race where the two contestants had two very different approaches. In the United States, the manned space program was a very public project carried out by a civilian agency. Its main architect, Wernher Von Braun, was a well-known public figure, and the missions lifting off from Cape Canaveral were carefully thought out incremental steps in a campaign to understand space and master the technology for operating in it.

On the other hand, the Soviet space program was extremely secretive with its head, Sergei Korolev, an official non-entity. In addition, manned spaceflight was unpopular with those in power. The Communist party saw the manned spaceflight program has having only propaganda value, while the Soviet military only tolerated it because the capsules could double as instrument carriers for orbital recon missions.

The result of this was a one-and-done approach to spaceflight with the key purpose of each flight to be a one-up on the Americans. This resulted in a long string of Soviet firsts, such as the first artificial satellite, the first animal in orbit, the first man in space, the first full day in orbit, the first two manned spacecraft in orbit simultaneously, the first woman in space, and the first three-man mission, but no follow ups.

Now it was to be the first spacewalk in a mission marked by the Kremlin's demand that it be carried out before the US astronaut Ed White could perform his walk during the Gemini 4 mission in June. On March 18, Leonov, then only 30-years old, and his pilot Belyayev lifted off from Baikonur Cosmodrome in a modified Vostok spacecraft fitted with a backup solid-fuel retrorocket pack and an inflatable airlock. Only two such craft ever flew. The first, the unmanned Cosmos 57, blew up two months before when a communications mix up caused a retro misfire, but that didn't prevent the team persisting with Voskhod 2.

The objective of the mission was very simple; get into orbit, do the spacewalk, and go home. So, once the Voskhod circled the Earth between 167 km (104 mi) and 475 km (295 mi), Leonov and Belyayev got to work.

For the excursion, Leonov wore a modified Vostok Sokol-1 intravehicular suit equipped with a life support backpack carrying 45 minutes of oxygen for breathing and cooling. Normal pressure suits of the time were designed to protect the crew in the event of capsule depressurization, which resulted in the wearer being bent into a sitting position to conform to the flight seat. This would not have allowed Leonov to exit the capsule, so his suit was tailored to inflate in a more upright posture.

To get out of the capsule, he used an inflatable airlock on the outside of the hatch that, when pressurized, extended in the form of a fabric tube with a hatch at the top. This system took only nine months to install from conception to completion and was necessary because the primitive electronics used in the Voskhod 2 needed air cooling. American spacecraft used miniaturized solid-state circuits, so they could be depressurized instead of using an airlock.

After sealing himself in the lock and depressurizing it, Leonov wormed his way out of the hatch attached to the capsule by a 5 m (18 ft) tether. As he exited, he became the first man ever to see the Earth from space without the aid of a camera or through a porthole as he looked down on the Mediterranean Sea. Meanwhile, a camera fitted on a boom recorded the event and sent live television images back to Earth.

Unfortunately, the momentous event was marred by the difficulties that Leonov soon encountered. Despite the fact that his only task was to take a few photographs, he had difficulty moving about and the suit ballooned, so he was unable to work the shutter for the camera mounted on his chest. He also had trouble recovering the boom-mounted camera and getting it back into the airlock.

The biggest problem, however, was getting back inside the spacecraft. Leonov's suit was ballooning so badly that his hands were sliding out of his gloves and it took so much effort to move that he was on the verge of heatstroke and later reported that he lost 6 kg (13.2 lb) in sweat, which ended up sloshing in the legs of his suit. Worse, he could no longer fit into the hatch.

In order to get inside,Leonov had to violate procedure and go in head first, only to get stuck. He then had to bleed oxygen from his suit so he could move – an extremely dangerous procedure that put him in danger of anoxia and the bends. But if he could not get in, then his only alternative to passing out was a suicide pill while Belyayev jettisoned him with the airlock.

Dangerous though Leonov's plan was, it worked and he managed to get back inside Voskhod. From start to finish, the first spacewalk lasted 12 minutes and 9 seconds.

Having completed history's first spacewalk, it was time for Voskhod to return to Earth after only 16 orbits, but that was by no means the end of the problems faced by Leonov and Belyayev. At first, they couldn't get the hatch to close properly and when they fired the explosive bolts to jettison the airlock, the spacecraft started to rotate wildly and damaged a vital sensor. In addition, the oxygen supply spiked to a dangerous level. One spark now would turn the space capsule into an incinerator.

Between the rotation and the damaged sensor, re-entry was delayed. Then the automatic re-entry system failed and they had to fly the craft manually. Then to top it off, the equipment module did not detach and the cosmonauts were subjected to high g forces as the capsule tumbled when it hit the atmosphere until the module tore free. Unlike Vostok, there were no ejector seats. This meant there was no way to escape the capsule as Yuri Gagarin had done on his flight, so the two men had to ride the capsule to the ground. Gagarin ejected by design before landing because his Vostok capsule was traveling too fast, but Leonov and Belyayev didn't have that option, so solid rockets were attached to the parachute shrouds to lessen the impact.

Voskhod 2 ended up landing hundreds of miles to the east of its target area and came down in a wooded area of Siberia in 6 ft (2m) of snow. To add insult to injury, the hatch automatically blew open and the capsule's heaters failed, so the men were now in sweat-soaked clothing and exposed to the elements.

The cosmonauts remained out of contact with Moscow for several hours, with many believing them dead, before a West German station picked up their signals. Even when they were finally located, recovery was extremely difficult in the rough terrain. As light faded, helicopters dropped wolf-skin boots, winter trousers, jackets, a blunt axe, and a bottle of cognac (which broke) for the men, who spent a very cold night in the capsule with bears and wolves roaming about.

At daybreak, men were dropped from a helicopter to cut down trees several miles away and provide a landing area for the recovery team. Though the cosmonauts were reached, they still had to spend a second night in the woods in a log cabin built by the rescue team before skiing 9 km (5.6 mi) to a recovery spot.

Leonov's spacewalk was more than just a first. It illustrates how dangerous and alien an environment space is and that if modern astronauts make it look easy, it's because they have decades of experience and progress to draw on. The Voskhod 2 mission also shows that the Right Stuff isn't a NASA monopoly and that the sort of cool-headed courage and professionalism shown by Leonov and Belyayev are just as important as any bit of hardware.

The Voskhod 2 capsule is on display at RKK Energiya in Korolev, Russia.

More details of the Voskhod 2 mission can be found in Alexei Leonov's autobiography, Two Sides of the Moon: Our Story of the Cold War Space Race.

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