What Really Happened to Yuri Gagarin, the First Man in Space?

Born in 1934 in Klushino, near Moscow, Gagarin was the son of a carpenter and a milkmaid. When he was still a child, Nazi forces invaded the U.S.S.R. and occupied the town. Everyone suffered – two of his siblings wound up in labor camps but survived the war.

Later, Gagarin attended various technical schools, but it was a flying club in Saratov that really grabbed his attention. Once he had his first taste of flight, he embraced his new passion and used his weekends learning to fly.

He joined the Soviet Air Force and became a full-fledged fighter pilot, gaining proficiency on planes like the MiG-15. In the meantime, he married Valentina Goryacheva, with whom he had two daughters.

In 1960, Soviet authorities chose 20 men to take part in the country's fledgling space program. The commission specified that the men be between 25 and 30 years old and less than 5 feet, 7 inches (1.57 meters) tall. Gagarin checked both boxes, and he was one of the lucky candidates selected for further training.

Then began rigorous physical training, which included dozens of parachute jumps over water, oxygen starvation tests, and isolation chamber procedures meant to weed out anyone who might melt down psychologically in space. Though the process was competitive, Gagarin stood out both for his physical skills and his exceptional personality.

He was charismatic, competent and simply likable, in part because of the ever-present smile on his face. His positive aura was a large part of why he was ultimately chosen for the Vostok 1 mission, just one week before launch. The Soviets knew that their soon-to-be-famous cosmonaut would need to look good in front of a camera for propaganda purposes. Gagarin's beaming smile fit the bill.

On April 12, 1961, the rocket lifted off from Baikonur Cosmodrome. Just minutes later, the former farm boy was the first human in space.

"Gagarin was very charismatic and well liked within the cosmonaut corps," says Howard McCurdy, a space policy expert and public affairs professor at American University. "He was apparently fearless. While [Sergei] Korolev, the chief spaceflight engineer, was popping tranquilizers, Gagarin was sitting calmly in the capsule."

In 1961, very little was known about spaceflight and what would happen to a human who was in weightlessness for longer than a few seconds. So there was a lot riding on this. Gagarin orbited our planet just a single time (108 minutes). He reached a maximum height of 203 miles (327 kilometers). During the flight, he ate, drank and monitored the onboard systems.

"Gagarin had no control over his spacecraft," says McCurdy. "According to sources at NASA, flight controllers gave Gagarin a key to the controls for use in an emergency, which he did not use. Otherwise, he was just a passenger on the spacecraft."

Gagarin's return to Earth wasn't the tidy sort of splashdown that we're used to witnessing these days. Instead, it was like something dreamed up by scriptwriters for a "Mission: Impossible" movie.

"Gagarin did not land with his Vostok space capsule," says McCurdy. "He jumped out of it and parachuted to the ground. Sort of a hair-raising way to land."

Even before he landed, the Soviets were trumpeting the trailblazing spaceflight. His safe return guaranteed worldwide celebrity.

Streets were named for him, and he was awarded the title of Hero of the Soviet Union by Nikita Khrushchev. Some called him the modern-day Christopher Columbus. He traveled the world, living proof of the success of the Soviet space program.

The celebrity cosmonaut visited dozens of countries in celebration of his incredible spaceflight – but he was barred from entering the United States. President John F. Kennedy wanted no part of celebrating the Soviet Union's accomplishment, which cast the U.S. as left behind in the Space Race.

Once his publicity tour ended, he slowly returned to flying. The air force promoted him multiple times, in large part to keep him out of airplanes and safely on the ground; no one wanted their international superstar to die young.

Yet, his bout with fame was unsettling. Gagarin took to drinking heavily, which concerned his superiors.

Still, he trained for space, and was named a backup for the Soyuz 1 mission. Gagarin's good fortune held – the 1967 mission failed catastrophically when the landing module's parachute failed to open, ending with the first in-flight spacecraft fatality, Vladimir Komarov.

Gagarin gave up drinking the next year. He recommitted himself to flying, and even participated in aerospace engineering in hopes of helping to create a reusable spacecraft.

In 1968, the famed pilot and cosmonaut took off on a routine training flight in a MiG-15UTI. Shortly thereafter, the plane crashed near the town of Kirzhach. Both Gagarin and flight instructor Vladimir Seryogin perished. Gagarin was just 32.

Immediately, the Soviets rushed to gloss over the incident, covering up details of the incident for decades. Lacking convincing explanations, conspiracy theories abounded – but none of them stuck.

In 2013, new evidence emerged thanks to the investigative work of Alexei Leonov, a former cosmonaut who was troubled by the death of his friend and fellow space traveler.

His (unconfirmed) explanation for the crash? An error in air traffic control. During the fateful flight, a Soviet Su-15, a model much larger than the hero's MiG-15, violated Gagarin's airspace. The turbulence caused Gagarin to lose control and ultimately plunge to his death.

Perhaps the embarrassment of losing a national icon to such a simple error was too much to admit publicly. Or maybe, as Leonov speculated, the authorities didn't want to make public that there was "a lapse" so close to Moscow. We may never know for sure. What we do know is that Gagarin's first and only space mission left an indelible mark on our world.

"People had been dreaming of flying in the air for millennia before the Wright Brothers achieved that in 1903," says Amy Foster, assistant history professor at the University of Central Florida, via email.

"The idea of humans flying in space was even more lofty. While both the United States and the Soviet Union had successfully launched living creatures by the time of Gagarin's flight, there were still questions about how the mission would affect a human. So, Gagarin's flight made flying in space not only achievable, but also a realistic endeavor."