The Vostok (Russian: Восток, translated as East) was a type of spacecraft built by the Soviet Union's space programme for human spaceflight.
The Vostok spacecraft was originally designed for use both as a camera platform (for the Soviet Union's first spy satellite program, Zenit
) and as a manned spacecraft. This dual-use
design was crucial in gaining Communist Party
support for the program. The basic Vostok design has remained in use for some forty years, gradually adapted for a range of other unmanned satellites
. The descent module design was reused, in heavily-modified form, by the Voskhod programme
The craft consisted of a spherical descent module (mass 2.46 tonnes, diameter 2.3 meters), which housed the cosmonaut
, instruments and escape system, and a conical 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.
There were several models of the Vostok leading up to the manned version:
Prototype spacecraft. Used to test basic systems and prove the concept. Flew six unmanned test missions in 1960.
Photo-reconnaissance and signals intelligence spacecraft . Later named Zenit spy satellite
The Vostok 3KA was the spacecraft used for the first human spaceflights
. They were launched from Baikonur Cosmodrome
using Vostok 8K72K
launch vehicles. The first flight of a Vostok 3KA occurred on 9 March 1961
. The first flight with a crew -- Vostok 1
carrying Yuri Gagarin
-- took place on 12 April 1961
. The last flight -- Vostok 6
carrying the first woman in space, Valentina Tereshkova
-- took place on 16 June 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. Also known as: Spuskaemiy apparat - 'Sharik' (sphere).
- Crew Size: 1
- Length: 5 m
- Diameter: 2.3 m
- Mass: 2,460 kg
- Heat Shield Mass: 837 kg
- Recovery equipment: 151 kg
- Parachute deploys at 2.5 km altitude
- Crew seat and provisions: 336 kg
- Crew ejects at 7 km altitude
- Ballistic reentry acceleration: 8 g (78 m/s²)
Equipment Module: Vostok PA. Also known as: Priborniy otsek.
- Length: 2.25 m
- Diameter: 2.43 m
- Mass: 2,270 kg
- Equipment in pressurized compartment
- RCS Propellants: Cold gas (nitrogen)
- RCS Propellants: 20 kg
- Main Engine (TDU): 397 kg
- Main Engine Thrust: 15.83 kN
- Main Engine Propellants: Nitrous oxide/amine
- Main Engine Propellants: 275 kg
- Main Engine Isp: 266 s (2.61 kN·s/kg)
- Main Engine Burn Time: 1 minute (typical retro burn = 42 seconds)
- Spacecraft delta v: 155 m/s
- Electrical System: Batteries
- Electric System: 0.20 average kW
- Electric System: 24.0 kW·h
- Total Mass:4,730 kg
- Endurance: Supplies for 10 days in orbit
- Launch Vehicle: Vostok 8K72K
- Typical orbit: 177 km x 471 km, 64.9 inclinaton
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 to Project Mercury
's conical design), which allowed for maximum volume while minimizing the external surface. Some control of the capsule was possible by way of positioning of the heavy equipment, which was placed in a manner that maximized the chance of the cosmonaut
while in a horizontal position. Even then, the cosmonaut experienced 8 to 9g.