Above: The descent module of the Vostok 3KA No. 3 spacecraft which carried Yuri Gagarin into space. The capsule's hatch can be seen on the left and the demo version of the ejection seat is on the right. A guide rail used by the ejection seat is well visible in the lower section of the main hatch. A storage locker can be seen above. Vostok carried enough provisions for a 10-day mission.
Origin of the Vostok spacecraft
The arliest studies of a manned spacecraft capable of orbital missions started at Korolev's OKB-1 around 1956. At the time, orbital flight was considered in parallel with possible piloted launches of ballistic (suborbital) rockets. (84)
Within Sergei Korolev's OKB-1 design bureau, which at the time was almost exclusively a missile development organization, all work on spacecraft was originally concentrated at Department No. 9 lead by Mikhail Tikhonravov. Tikhonravov's team would be instrumental in the development and launch of the world's first artificial satellite. Within the 9th department, a group led by Nikolai Belousov studied the possibility of launching a piloted rocket on a ballistic arch as high as 100 or 200 kilometers. The work was essentially advancing the proposals put forward by Tikhonravov after World War II and relying on the VR-190 vehicle deriving from German the A-4 (V-2) ballistic missile. Obviously, Belousov's team could take advantage of much more advanced and powerful rockets, which became available in the 1950s. Engineers also made comparison between a vehicle which would "hop" into space on a ballistic trajectory and a true orbiting spacecraft. The suborbital flight, while requiring most attributes of a real space mission, would provide only 2-4 minutes of weightlessness in a 10-15-minute trip. However even a single-orbit flight would enable the pilot to be weightless for an hour and a half, making the scientific value of the mission much higher. Although suborbital vehicles could be launched by smaller rockets, they were eventually ruled out in favor of a true orbital spacecraft.
Around the same time, the possibility of a winged orbiter was studied by K.S. Shustin, who worked in OKB-1 under Gleb Maksimov. However it was soon determined that problems of aerodynamics and thermal protection of such a vehicle would push the implementation of the project years behind the development of a capsule-like spacecraft.
By the end of 1957, a young engineer from the NII-4 research institute of the Ministry of Defense, Konstantin Feoktistov, transferred to Department No. 9. Belousov first proposed Feoktistov to research the stability of a vehicle reentering the atmosphere on a ballistic trajectory -- a key engineering problem affecting the architecture of the future manned spacecraft. Feoktistov started his research not without a foundation. By that time, OKB-1 had already developed a method to calculate the stability of ballistic missile warheads during reentry. The additional research conducted during January-February 1958 demonstrated that any tumbling or shaking of a body reentering the atmosphere would quickly dissipate, if the center of gravity of the vehicle did not coincide with the center of aerodynamic pressure. This basic principle would later become the cornerstone of the descent module design for the Vostok spaceraft.
With ever widening horizons of responsibilities at Department 9, its head, Mikhail Tikhonravov, offered his deputies Gleb Maksimov and Konstantin Feoktistov to choose the leadership of two newly created groups: one specialized in automated planetary probes and another concentrating on manned vehicles. (88) Feoktistov took charge of the latter field, essentially laying the foundation for the prolific and unique school of manned spacecraft development in the USSR. With the strong support of the management from Belousov to Tikhonravov to Korolev, Feoktistov's group quickly grew to a several-dozen-strong collective. Since the team consisted largely of recent college graduates, it became known in OKB-1 as the "kindergarten."
Vostok spacecraft during assembly.
The preliminary design for the future manned spacecraft was officially concluded on May 15, 1958, favoring an orbital vehicle. A three-stage rocket for unmanned lunar missions would be re-purposed for manned missions in Earth's orbit. The lifting capabilities of the rocket allowed it to carry an almost five-ton spacecraft into low Earth orbit.
The final design of the Vostok spacecraft consisted of two main components: a descent module with the pilot cabin and the instrument module equipped with a braking engine.
As a purely experimental vehicle, Vostok had to safely carry a pilot in orbit and return him/her to Earth. The main flight control function was limited to orienting the spacecraft tail first for the firing of the braking engine prior to reentry into the atmosphere. The braking engine had to slow down the spacecraft by around 140 meters per second to ensure the safe return of the vehicle. Firing of the engine would be commanded by a programming timer (84), later known as PVU Granit.
Since the successful completion of the reentry maneuver meant life or death for the pilot and the braking engine could not be backed up by any other hardware, engineers decided to launch Vostok missions into a 180 by 235-kilometers orbit. At that altitude, the density of the upper atmosphere would be enough to slow down and send the spacecraft back to Earth roughly five days after launch, with a margin of error of 2.5 days. Vostok would have enough food, water, air and power onboard to support a 10-day mission.
Proposed Vostok modifications
Along with the development of a regular version of the Vostok spacecraft, OKB-1 and its contractors studied alternative designs, particularly a descent module powered by a helicopter-like rotor. This design was particularly favored by Korolev. The key goal of the project was to have a complete control of the landing trajectory, ending dependency on winds during a parachute descent. The idea was never implemented.
Upon the conclusion of six manned flights of Vostok in 1963, new missions were under consideration. Orbital flights carrying animals to an altitude of 1,000-1,200 kilometers and lasting up to 10 days were planned, apparently to study the effects of radiation beyond low orbits shielded from space rays by the magnetic field of the Earth. There were also plans to equip the Vostok spacecraft with an additional solid-propellant motor which could serve as a backup for the main braking engine. This improvement would eliminate the self-imposed limit for an orbital altitude of Vostok missions in order to enable natural reentry of the spacecraft following main engine failure.
To ensure safe touchdown of the pilot inside Vostok instead of ejection in mid air, developers proposed to install a special landing engine on the descent capsule. The device would reduce the impact speed from 10 to 2 meters per second. Vostok's ejection seat was still expected to stay onboard as an emergency feature. (84) Soft-landing engines did find their way into the design of the Voskhod spacecraft, however, their passengers would not have ejection seats due to mass limitations of the multi-seat incarnation of the spacecraft.
Vostok's dog missions
In preparation for the first manned orbital mission, four 1K prototypes of the Vostok spacecraft carried pairs of dogs each in 1960. Two of these missions failed killing four dogs. In March 1961, a pair of unmanned versions of the Vostok spacecraft designated 3KA carried a single dog each during final dress rehearsals of Gagarin's upcoming flight. Both returned their passengers safely to Earth, clearing the way for the historic launch.
An overview of the early Russian manned space flight projects:
An overview of the missions within Vostok and Voskhod programs:
Vostok project development milestones:
1959 Jan. 5: Soviet government (TsK KPSS and Soviet of Ministers) decree on the selection of first cosmonauts.
1959 May 22: Soviet government (TsK KPSS and Soviet of Ministers) decree on the selection of first cosmonauts.
1960 end of April: First prototype of the Vostok spacecraft arrives to Tyuratam. (100)
Page author: Anatoly Zak; last update: June 4, 2015
Page editor: Alain Chabot; Last edit: April 30, 2011
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A rare photo shows the key developers of early Soviet manned spacecraft (left to right): N. M. Tereshenkova, K. S. Shustin, V. V. Molodtsov, K. P. Feoktistov, L. A. Gorshkov, V. Ye. Lyubinsky.
Early version of the Vostok spacecraft. Copyright © 2001 Anatoly Zak
A container designed to return live animals to Earth after test flights of the Vostok spacecraft. Copyright © 2001 Anatoly Zak
Although this hatch was attributed to Gagarin's flight, it is more likely a part of unmanned Vostok missions. The dual window in the hatch was designed to monitor dogs onboard prior to launch. Copyright © 2011 Anatoly Zak
Pre-launch processing of the Vostok spacecraft. Credit: RKK Energia
A close-up view of the SIS-1-3KA pilot control panel of the Vostok spacecraft. Copyright © 2001 Anatoly Zak
A mockup of the braking engine of the Vostok spacecraft. Copyright © 2001 Anatoly Zak
The Vostok spacecraft reentry capsule and the protective pressure suit. Copyright © 2001 Anatoly Zak
All cosmonauts flying onboard Vostok spacecraft were wearing the SK-1 "full-pressure" suits. Copyright © 2002 Anatoly Zak
The Vostok spacecraft ejection seat. Copyright © 2001 Anatoly Zak
The actual reentry capsule of the Vostok-6 spacecraft, the Gagarin's capsule is on the background. Copyright © 2001 Anatoly Zak
The reentry capsule of the Voskhod-2 spacecraft with an attached copy of the airlock and a mannequin illustrating the spacewalk by Alexei Leonov. Copyright © 2001 Anatoly Zak