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Descent

Above: Contrary to previous reports that Gagarin landed where expected or overflew his touchdown area, Vostok's descent module had landed far short of target.

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Previous chapter: Gagarin's orbital flight


A bumpy ride home

Everything looked good until the conclusion of the 40-second burn of the braking engine, initiated successfully at 10:25 Moscow Time. In his post-flight report, Gagarin wrote:

"As soon as TDU (braking engine) shut down, there was a sharp jolt. The spacecraft started spinning about its axis with very high speed. The Earth was passing in the Vzor (window) from top to bottom and from right to left. The speed of rotation was around 30 degrees per second, no less.. Everything was spinning. One moment I see Africa -- it happened over Africa -- another the horizon, another the sky. I barely had time to shade myself from the sun, so the light did not blind my eyes. I put my legs toward the (bottom) window, but did not closed the blinds. I wanted to find out myself what was going on." (230)

Gagarin, was expecting the separation of his reentry capsule from the instrument module to take place 10-12 seconds after the deorbiting burn, however it did not take place. In the meantime, the spacecraft continued tumbling wildly, as it approached denser layers of the atmosphere. Despite this situation, Gagarin wrote that he believed everything was on track for a safe landing:

"On the phone I reported that the separation had not taken place. I decided that the situation was not an emergency, with the code system I transmitted VN4, which stands for "Vse Normalno," (Everything alright)." (230)

According to Gagarin, the separation finally did take place at 10:35, when the spacecraft was over the Mediterranean Sea.

Braking glitch

For decades, the very fact, not to mention the cause of the whole incident with the separation of the capsule and its instrument module remained unknown to the general public. Even after Gagarin's report was published, at least one participant of the events denied any problems during the reentry and tried to explain the situation by Gagarin's confusion about the real time of the separation. However thanks to the efforts of the Novosti Kosmonavtiki magazine, and, particularly, its tireless researcher Igor Lissov, (232) a credible picture of the event had finally been painted during 2000s.

As it turned out, a single valve within the braking engine failed to shut completely at the beginning of the engine burn, letting some fuel leak out and avoid the combustion chamber. As a result, the engine "ran out of gas" and shut down around a second earlier than scheduled. The aborted maneuver slowed the spacecraft by 132 meters per second instead of the programmed 136 meters per second. Even though it was enough to push the spacecraft off its orbit toward reentry, it was apparently not enough for the "punctual" flight control system to generate the nominal command to cut off the engine.

In the absence of a proper cutoff command, the propellant lines of the engine remained open, after it ran out of fuel and stalled. As a result, the pressurization gas and remaining oxidizer continued escaping through the main nozzle and steering thrusters, causing the spacecraft to spin wildly.

Although the engine was later cut off by a timer, the lack of delivered thrust also caused the flight control system to scrub the primary sequence for the separation between the reentry vehicle and the instrument module. Fortunately, the separation did take place some 10 minutes later, (or around 10:36 Moscow Time), supposedly, as a result of an emergency command. The exact mechanism which generated this backup command was a subject of debate as late as 2010. The prevailing theory was that temperature sensors reacting to the heat of atmospheric reentry triggered the separation. (233) However, estimates made by Igor Lissov showed that by 10:36 the spacecraft could only have descended to an altitude of 150-160 kilometers -- likely still too high for temperature sensors to sound the alarm. (464) Therefore, this aspect of the flight still remained under a question mark as of 2010.

Reentry and landing

As the spacecraft plunged into the atmosphere, Gagarin saw a bright crimson glow appear behind his windows. It was accompanied by the crackling noise of thermal protection layers burning in the heat of atmospheric reentry.

Gagarin estimated that at their peak g-forces exceeded 10:

"There was a moment, about 2-3 seconds, when data on the control gauges started looking blurry. It was starting turning gray in my eyes. I braced and composed myself. It helped, everything kind of returned to its place." (230)

Potentially much more troubling and unexpected than g-loads was the burning smell in the cabin. Fortunately, it was very slight and short-lived, according to Gagarin's recollections after the flight.

As G-forces subsided and the capsule continued descending safely, Gagarin prepared to eject from his craft. At an altitude of seven kilometers, the main hatch of the capsule was jettisoned and seconds later, the pilot ejected. The main parachute deployed successfully, however the backup chute came out later as well and, after some delay, deployed. As a result, Gagarin landed under two parachutes. For six minutes during the parachute descent Gagarin struggled to open a valve for breathing atmospheric air. The device stuck below his external orange layer and he had to use a mirror to pull the valve.

According to Gagarin, he gently hit the soft surface of freshly plowed dirt in an open field not far from the town of Engels. Later, his landing was determined to be not far from the village of Smelovka, in the Ternovsky District near Saratov. (228) On July 17, 2012, the Russian government declared a monument three kilometers southeast of the Novaya Ternovka station in the Saratov Oblast, Engels District, a federal cultural heritage site.

After landing

A woman and her daughter were initially scared when they saw a man dressed in a bright-orange suit and a helmet walking toward them across the field. However they overcame their doubts and responded to his greetings. They helped alert workers from the local collective farm, who then organized a car to get to the local military base.

As it transpired, Gagarin's nominal landing site was located 300 kilometers further northeast, near the regional center of Pestravka, 89 kilometers from Kuibyshev (Samara). (468) Headquarters of the search and rescue team led by K. T. Tsedrik, the Commander of the Volga military district of the Soviet Air Force, were located at the Kryazh airfield, 79 kilometers from Pestravka.

On the morning of April 12, search helicopters and the plane with doctors trained as sky divers appeared over the expected landing site, but Gagarin's capsule nowhere to be found.

One of the helicopters, which flew back along the Vostok's expected flight path finally spotted Gagarin and his accidental saviors waving hands in an open field around 300 kilometers southwest of the planned landing site. Helicopter landed, picked Gagarin onboard and eventually made it to the airfield in Engels. This runway was the closest to the actual landing site and became the defacto meeting point for the rescue team. An Il-14 aircraft with medics spotted landing site of the descent module too late for the scheduled post-flight medical checks of the cosmonaut and the team was redirected to Engels. Lt. Colonel Vitaly Volovich, who led the medical team, had to wave his handgun in order to elbow through the excited crowd near the check point of the airfield. He finally caught up with Gagarin on the second floor of the airport building. However, he got his first chance to measure Gagarin's pulse and blood pressure only onboard of Il-14 heading from Engels to Kuibyshev (Samara). All Gagarin's vital signs were normal.

Gagarin spent two days at the country house of the local party leadership near Kuibyshev, while Moscow was hectically preparing for his triumphant arrival. On April 14, 1961, he flew from Kuibyshev to Moscow onboard a passenger Il-18 aircraft. As the plane was approaching the city, a group of fighter jets provided an escort. At the tarmac, Nikita Khrushchev with a full entourage of Communist Party officials along with a cheering crowd of onlookers were watching Gagarin dressed in his air force uniform emerge from the aircraft and walk on the red carpet to a hero's welcome by the Soviet leader. (A lace on one of Gagarin's shoes had gotten undone during this historic walk captured in timeless film footage and photographs.)

Investigation of launch problems

A day after the launch, as the whole USSR celebrated Gagarin's triumph, a group of engineers (stranded in Tyuratam by Korolev's strict order) had to go through historic but mundane task of studying telemetry tapes recorded during the launch. That's when they discovered the failure of the radio-control system, RUP, monitoring the rocket's range and acceleration and responsible for issuing the engine cutoff command on the core stage known as Block A. Radio engineers led by Mikhail Borisenko explained the problem by the failure of the power converter. (466)

As remembered by Nikolai Semenov, an engineer of the RUP system, a critical signal to cutoff the engine "stumbled" inside one of the deciphering units and then came out the fraction of a moment later than required. It distorted the rocket's range readings, causing a calculating device at one of ground stations of the RUP radio-control network to issue the cutoff command slightly later than planned. (51)

Estimates made by Igor Lissov suggest that the 0.6-0.7-second delay of the engine shutdown would be enough to send the spacecraft around 100 kilometers higher than required. (467)

Upon learning of the problem, Korolev ordered to exclude the RUP network (originally developed for controlling the R-7 ICBM) from further orbital launches. (51)

Implications

Launched into space from the abyss of secrecy, Gagarin returned to Earth an international celebrity. The shockwave of the Vostok mission spread far outside the Soviet space program and long outlived its hero.

Following Sputnik, Gagarin dealt another major blow to American nationalism. At the same time, Vostok solidified American determination to invest heavily into their fledgling manned space program and made it politically easier for the US government to commit to the risky and ambitious goal of landing a man on the Moon within ten years. Along with Sputnik, Gagarin's mission helped create an oversized, overpriced and technologically dead-ended Apollo program, before its own success would reveal that it had no future beyond scoring points with the Soviets. Until today, popular American books and magazine articles on the history of space exploration, which are largely oblivious of any developments outside of the United States, do make an exception for Sputnik and Gagarin.

At the same time, Gagarin's leap above the Earth helped create the deceiving appearance of the Soviet Union as the most advanced and forward-looking nation on Earth. With Vostok, the caprice of history handed the Kremlin the kind of arrogance it had just stripped off the White House. The Soviet leader, Nikita Khrushchev and his much more conservative successors made Gagarin one of the most prominent icons of the Soviet system, while continuing down the path of self-destructing economic policies, unchecked arms race, isolation and oppression of any dissent. Ironically, the Soviet military industrial complex, which made Gagarin's success possible, also contributed to the economic bankruptcy and the ultimate demise of the very system this achievement was supposed to advance. In the meantime, half a century after Gagarin's pioneering mission, the world's manned space program was still looking for direction.

 


APPENDIX

Sites related to Gagarin's landing:

Site's role
Location
Latitude
Longitude
Primary (nominal) landing site of the Vostok 3KA No. 3 mission
Town of Pestravka
52.40 North
49.96 East
Actual landing site
Village of Smelovka
51.16 North
45.58 East
Operational headquarters of the search and rescue team
Kryazh airfield
53.11 North
50.10 East
Forward base of the search and rescue team
Pugachev airfield
-
-

Main records officially claimed by the USSR at the conclusion of the first manned Vostok flight:

  • Record flight duration: 108 minutes
  • Record altitude 327,7 kilometers
  • Record mass lifted to this altitude: 4,725 kilograms

 

Next chapter: Gherman Titov's mission onboard Vostok-2

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Page author: Anatoly Zak; Last update: July 25, 2012

Page editor: Alain Chabot; Last edit: April 8, 2011

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PICTURE GALLERY

TDU

A mockup of the braking engine of the Vostok spacecraft. Copyright © 2001 Anatoly Zak


Gagarin

A monument to Yuri Gagarin faces the rising Moon over the Baikonur Cosmodrome's Site 2, where the first cosmonaut of the planet spent his last night before the historic flight in April 1961. Copyright © 2001 Anatoly Zak


Gagarin

A Soviet period exhibit featuring the Pravda newspaper, a mouthpiece of the ruling Communist Party, published on April 13, 1961. In the orwellian fashion of changing the past, censors of the Brezhnev era cut out a part of the publication, in an apparent attempt to erase any memory of Nikita Khrushchev, as a revenge for his efforts to expose the crimes of Stalinism. The display likely no longer exist. Click to enlarge. Copyright © 2001 Anatoly Zak


Gagarin

Click to enlarge

Gagarin

Yuri Gagarin became the subject of numerous monuments throughout the Soviet Union. Click to enlarge.