On April 12, 1961, Soviet news agencies announced that Red Air Force Major Yuri A. Gagarin had just orbited the earth in a spacecraft named Vostok. Unknown and anonymous the day before Gagarin, the world’s first cosmonaut, abruptly became an international celebrity.

Development of the Vostok spacecraft began in 1958 under Sergei Korolev’s leadership. Initially, Korolev supported manned orbital missions with a lifting reentry vehicle. Such a complex spacecraft would take considerable time and effort to build. One of Korolev’s engineers, Konstantine Feoktistov, argued in favor of a much simpler spherical ballistic spacecraft. The aerodynamics of spheres were well known and by carefully locating the center of gravity, the capsule would automatically orient itself during reentry, which simplified the control and guidance systems. Korolev’s design bureau completed the preliminary design by March 1959, and finished the first test model by year’s end.

Vostok contained more than 9 miles of wiring, 240 valves, and 6,000 transistors. It had a spherical reentry module attached to an instrument module. Resembling two truncated cones attached base to base, the instrument module contained most of the spacecraft batteries, radio transmitters, TDU-1 liquid fuel retrorocket, attitude control thrusters and thermal control system. Four metal bands secured the reentry capsule to the instrument section. The cosmonaut sat in an ejection couch in the sphere. After reentry, the pilot ejected and landed beneath a personal parachute. This was because the landing impact of Vostok, even beneath its parachute, was too high. In case the booster malfunctioned, the ejection seat doubled as the launch escape system.

To boost Vostok into orbit, Korolev used the R-7 intercontinental ballistic missile with an upper stage. The R-7 had been the booster for the world’s first artificial satellite, Sputnik-1.

On the morning of April 12, Gagarin arrived at the launch pad in a gray-green bus a little before 7:00 a.m. Gagarin stepped off the bus followed by his backup cosmonaut, Gherman Titov. Both wore orange-colored space suits with black leather boots and white helmets. The letters “CCCP” had been stenciled in red across the top of their helmets. The Zvezda Bureau had fabricated the suits, designated SK-1. An orange outer layer covered the pressure suit assembly.

“What a glorious sun!” exclaimed Gagarin as he stepped from the bus. After a few remarks to the launch crew, he rode the elevator to the top of the gantry alongside the rocket. At the top platform, he surveyed the countryside and waved one last time to the workers below. Then, he boarded the capsule. Technicians sealed the hatch after him. Gagarin established radio contact with fellow cosmonaut Pavel Popovich who was in the control center. About an hour later, ground control determined the hatch had not been sealed properly. Technicians rushed to the pad, opened the hatch and resealed it. Throughout the countdown, Gagarin remained calm, joking with mission control.

Finally, the launch control officer, Leonid A. Voskresensky, called out the final commands: “Bleed-off… Hold… Ignition… Switch to launch… Lift off!” Vostok-1 blasted off from the Baikonur Cosmodrome at 9:07 AM. Sitting atop the 125-foot tall rocket, Gagarin heard the whine of the propellant pumps followed by a roar as the engines ignited. As the rocket climbed away from the pad, an exuberant Gagarin radioed “Let’s go!”

Acceleration reached a peak of 5 Gs, which meant Gagarin felt as though he weighed five times his normal weight. Throughout the ordeal, he continued talking to Popovich, reporting he felt fine. When the rocket was beyond the lower atmosphere, the shroud that covered Vostok separated. For the first time, Gagarin could look out the portholes and see the Earth below. Fourteen minutes after launch, he was in orbit. Only after receiving confirmation that Vostok-1 was in orbit did Radio Moscow broadcast the news to the world.

Reporting no sense of disorientation from weightlessness, Gagarin sampled food from a squeeze tube and drank some water. Crossing into darkness, he marveled at the view, comparing it to being in a large planetarium. Emerging from the Earth’s shadow, the Vzor optical system locked onto the sun and commanded the maneuvering jets to fire, placing Vostok in the proper orientation. A minute later, while passing over Cape Horn, Chile, Gagarin reported: “The flight is proceeding normally.”

Since the effects of weightlessness were still unknown, the manual flight controls were disengaged for Vostok-1. Just in case something went wrong and Gagarin had to take control, a three-digit code had been programmed into the logic clock that could activate the manual system. The code was in a sealed envelope in the cabin. Throughout the flight, everything worked properly and Gagarin never had to open the envelope. Over Africa, the automatic controls placed Vostok in the proper position for retrofire. Ten minutes later, the rocket fired and Gagarin began his fiery return to Earth.

Immediately following retrofire, with Vostok still 3,700 miles from its landing point, explosive bolts released the four metal bands that held the reentry capsule to the equipment section. No longer needed, the equipment section was supposed to burn up on reentry well clear of the reentry capsule. An electrical umbilical did not separate, however, and Gagarin began his reentry with the equipment section still attached. Vostok tumbled wildly until reentry heating burned through the umbilical.

During reentry, Gagarin looked out the portholes and saw streaks of fire as the sphere’s exterior reached 2,000 degrees. He next saw the blackness of space give way to a blue sky. The drogue chute slowed Vostok to about 450 miles per hour. Bracing himself, Gagarin watched the hatch blow off at 26,000 feet. Two rockets ignited, shooting the ejection seat out of the cabin. At 13,000 feet, the seat fell away and Gagarin descended beneath an orange and white parachute. He’d made numerous parachute jumps over the area while training, so the scenery was quite familiar. Floating under the canopy, he picked out familiar landmarks. He landed on a collective farm near the village of Engels, just 108 minutes after leaving the Baikonur Cosmodrome.

A woman and her six-year old granddaughter were nearby, planting potatoes. She offered him something to eat and drink, but his first concern was to get to a telephone and call in his location. The capsule was nearby, still too hot to touch. More villagers soon arrived, followed by official search parties.

Soviet Premier Nikita Khrushchev personally decorated him during a ceremony in Red Square. He received the title of Hero of the Soviet Union and the Order of Lenin. Other accolades included a gold medal from the British Interplanetary Society.

Written by Greg Kennedy on April 11th, 2013 , Space History

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    john werneken commented

    Thank you so much. Sputnik and Vostok were two of the early bookends of my life – closely following the independence Ghana and the invasions of Hungary and Suez, and shortly preceding the assassination of President Kennedy.

    I have a couple of disappointments in my 65 years…and the fact that humans in space NEVER really got any farther is as big as any. Generally I don’t believe in the concept of community, but I do believe in the future. I feel no obligation to my fellows, but major obligation to those who come after us.

    I feel my generation has failed. The Vietnam War did not matter all that much, except to participants, but the failure to build an infrastructure to annex off-Earth resources I think is over-shadowed ONLY by the success in not exterminating ourselves, so far anyway.

    April 12, 2013 at 1:09 am