 Model of Vostok 3KA spacecraft with third stage of launcher. | |||
| Manufacturer | OKB-1 | ||
|---|---|---|---|
| Designer | Sergei Korolev | ||
| Country of origin | Soviet Union | ||
| Operator | OKB-1 | ||
| Applications | Single-pilot Earth orbit | ||
| Specifications | |||
| Crew capacity | 1 | ||
| Dimensions | 2.43 meters (8.0 ft) diameter x 4.55 meters (14.9 ft) long | ||
| Regime | Low Earth orbit | ||
| Production | |||
| Status | Retired | ||
| Launched | 13 | ||
| Retired | 9 | ||
| Failed | 2 | ||
| Lost | 2 | ||
| Maiden launch | 15 May 1960 Korabl-Sputnik 1 | ||
| Last launch | 16 June 1963 Vostok 6 | ||
| Related spacecraft | |||
| Derivatives | Foton Voskhod Zenit Bion | ||
| Configuration | |||
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Vostok (Russian:Восток, translated as "East") was a class of single-pilot crewedspacecraft built by theSoviet Union. The firsthuman spaceflight was accomplished withVostok 1 onApril 12, 1961, by SovietcosmonautYuri Gagarin.
TheVostok programme made six crewed spaceflights from 1961 through 1963. This was followed in 1964 and 1965 by two flights of Vostok spacecraft modified for up to three pilots, identified asVoskhod. By the late 1960s, these were replaced withSoyuz spacecraft, which are still used as of 2025[update].
The Vostok spacecraft was originally designed for use both as a camera platform (for the Soviet Union's first spy satellite program,Zenit)[1] and as a crewed spacecraft.[2] Thisdual-use design was crucial in gainingCommunist Party support for the program. The basic Vostok design has remained in use for some 40 years, gradually adapted for a range of other uncrewedsatellites. The descent module design was reused, in heavily modified form, by theVoskhod program.
The craft consisted of a spherical descent module (mass 2.46 tonnes, diameter 2.3 meters), which housed thecosmonaut, instruments and escape system, and abiconical instrument module (mass 2.27 tonnes, 2.25 m long, 2.43 m wide), which contained propellant and the engine system. On reentry, the cosmonaut would eject from the craft at about 7,000 m (23,000 ft) and descend via parachute, while the capsule would land separately. The reason for this was that the Vostok descent module made an extremely rough landing that could have left a cosmonaut seriously injured.
The ejector seat also served as an escape mechanism in the event of a launch vehicle failure, which at this early phase of the space program was a common occurrence. If an accident occurred in the first 40 seconds after liftoff, the cosmonaut would eject from the spacecraft and parachute to Earth. From 40 to 150 seconds into launch, ground controllers could issue a manual shutdown command to the booster. When the launch vehicle fell to a low enough altitude, the cosmonaut would eject. Higher altitude failures after shroud jettison would involve detaching the entire spacecraft from the booster.
One problem that was never adequately resolved was the event of a launch vehicle malfunction in the first 20 seconds, when the ejector seat would not have enough time to deploy its parachute. LC-1 at the Baikonour Cosmodrome had netting placed around it to catch the descent module should the cosmonaut eject while still on the pad, but it was of doubtful value since he would likely end up landing too close to the exploding booster. An accident in the initial seconds of launch also likely would have not put the cosmonaut in a position where he could make a survivable ejection and in all probability, this situation would have resulted in his death. A 2001 recollection by V.V. Molodsov stated that Chief DesignerSergei Korolev felt "absolutely terrible" about the inadequate provisions for crew escape on the Vostok during the opening seconds of launch.
There were several models of the Vostok leading up to the crewed version:
Prototype spacecraft. This was used in theKorabl-Sputnik 2 mission, in which the first animals were recovered from orbit.
Photo-reconnaissance and signals intelligence spacecraft. Later namedZenit spy satellite.
The Vostok 3KA was the spacecraft used for the firsthuman spaceflights. They were launched fromBaikonur Cosmodrome usingVostok 8K72K launch vehicles. The first flight of a Vostok 3KA occurred on March 9, 1961. The first flight with a crew—Vostok 1 carryingYuri Gagarin—took place on April 12, 1961. The last flight—Vostok 6 carrying the first woman in space,Valentina Tereshkova—took place on June 16, 1963.
A total of 8 Vostok 3KA spacecraft were flown, 6 of them with a human crew.
Specifications for this version are:
Reentry Module: Vostok SA. SA stands forSpuskaemiy apparat - descent system. It was nicknamed "Sharik" (Russian:шарик,lit. 'little sphere').
Equipment Module: Vostok PA. PA stands forPriborniy otsek - instrument section.
The Vostok capsule had limited thruster capability. As such, the reentry path and orientation could not be controlled after the capsule had separated from the engine system. This meant that the capsule had to be protected from reentry heat on all sides, thus explaining the spherical design (as opposed toProject Mercury's conical design, which allowed for maximum volume while minimizing the heat shield diameter). Some control of the capsule reentry orientation was possible by way of positioning of the heavy equipment to offset the vehicle center of gravity, which also maximized the chance of thecosmonaut survivingg-forces while in a horizontal position. Even then, the cosmonaut experienced 8 to 9g.
If theretrorocket failed, the spacecraft would naturally decay from orbit within ten days, and the cosmonaut was provided with enough food and oxygen to survive until that time.
| Uncrewed | | |
|---|---|---|
| Crewed | ||
| Cancelled | Vostok 7 to 13 (incorporated intoVoskhod programme) | |
| Related |
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