On March 18, 1965, Soviet cosmonaut Alexei Leonov left his spaceship Voshkhod 2 for 20 minutes to become the first man ever to walk in space, according to NASA.

With this spacewalk, the Soviets pulled ahead of the U.S. in the space race. It was a historic first, but it was also a near disaster.

The secrecy of the Soviet space program required that very few people know about the plan for Leonov’s journey from the spacecraft. His family wasn’t even aware of the spacewalk until it was televised.

“When my four-year-old daughter, Vika, saw me take my first steps in space, I later learned, she hid her face in her hands and cried, ‘What is he doing? What is he doing? Please tell Daddy to get back inside,’”he wrote in an article for Smithsonian's Air & Space. His elderly father was also surprised and upset, and expressed to journalists that his son was acting as a delinquent and should be punished for his behavior.

After 10 minutes in space, crewmate Pavel Belyayev informed Leonov that it was time to re-enter the spacecraft. But Leonov quickly realized that, and his gloves and boots no longer were fitting snugly, the BBC reported. He was unable to use his gloves to pull himself into the airlock, and the suit was too inflated to fit. He was perspiring as well, which affected his vision.

With some quick thinking, the cosmonaut leaked half of the air out of his spacesuit through an attached valve, at the risk of starving himself of oxygen.

“I began to get pins and needles in my legs and hands. I was entering the danger zone, I knew this could be fatal,” Leonov told the BBC. Decompression sickness was setting in.

The slow leak of oxygen reduced the pressure within Leonov’s suit, and he was able to throw himself into the airlock head first, Air & Space reported. The head-first entry put Leonov in the wrong direction within the airlock, and the was unable to enter the spacecraft. He then had to exert himself to turn around within the small airlock with the bulk of his suit, and make sure his tether was securely within the airlock as well.

Leonov did get safely inside the spacecraft, but that didn’tend the challenges within Voshkhod 2. When the cosmonauts fired the explosive charges to eject the craft into space, the spacecraft rotated, disorienting the crew, according to the BBC. In an unrelated incident, the oxygen levels began rising within the craft, rendering the cabin’s atmosphere dangerously flammable. In time, the cosmonauts lowered the oxygen to a more reasonable level, but had the engines sparked, the crew would have certainly perished.

As Leonov and Belyayev prepared to re-enter Earth’s atmosphere, an equipment failure forced the crew to fire the rockets manually instead of using the craft’s computer. This had never been done, and according to Business Insider, one small mistake during this task, which required incredible precision, . Though the burn was precise and directed Leonov and Belyayev safely to Earth, they had little control over their landing. The descent module touched down in a Siberian forest. It took seven hours for a monitoring station in West Germany to pick up their signal, according to the BBC. Swimming in perspiration from their descent, the two had to ring the dampness from their suits as temperatures dropped to minus 13 degrees F.

Finally, a rescue team approached on skis. The next day, Belyayev and Leonov skied the more than five miles to the helicopter with the rescue team.

Despite all of the challenges involved in the first spacewalk, Leonov describes his experience as a man enchanted. “You just can’t comprehend it,” he told the BBC. “Only out there can you feel the greatness, the huge size of all that surrounds us.”

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