Soyuz 7K-OK

Soyuz 7K-OK

Soyuz 7K-OK(A) spacecraft with an active docking unit
Manufacturer	Korolev
Country of origin	Soviet Union
Operator	Soviet space program
Applications	Carry three cosmonauts to orbit and back
Specifications
Regime	Low Earth orbit
Production
Status	No longer in service
Built	16
Launched	16
First launch	Kosmos 133, 1966
Last launch	Soyuz 9, 1970
Related spacecraft
Derived from	Soyuz-A (concept only)
Derivatives	Soyuz 7K-OKS (Salyut 1 ferry) Soyuz 7K-L1 (lunar) Soyuz 7K-LOK (lunar) Soyuz 7K-T (successor)

Soyuz 7K-OKS (Salyut 1 ferry) Soyuz 7K-L1 (lunar) Soyuz 7K-LOK (lunar)

Soyuz 7K-OK was the first generation of Soyuz spacecraft in use from 1967 to 1971. This first generation was used for the first ferry flights to in the Salyut space station program; Soyuz spacecraft in their current generation are still in use to ferry crew to and from the ISS.

This generation is notable for the only fatalities of the Soyuz programme as of 2016^[update], with Soyuz 1 in 1967 (sole crew-member killed by parachute failure) and Soyuz 11 in 1971 (crew killed by depressurisation during reentry).

The first unmanned automated docking in the history of spaceflight, between Kosmos 186 and Kosmos 188 in 1967, was achieved with this generation of Soyuz spacecraft. The generation encompasses furthermore the first docking between two manned spacecraft (Soyuz 4 and Soyuz 5), the longest manned flight involving only one spacecraft (the 18-day flight of Soyuz 9 in 1970) and the first successful manning of the first space station in the history of space flight (Soyuz 11 and Salyut 1 in 1971).

The Soyuz 7K-OK vehicles carried a crew of up to three without spacesuits. The craft can be distinguished from those following by their bent solar panels and their use of the Igla automatic docking navigation system, which required special radar antennas.

The 7K-OK was primarily intended as a variant of the 7K-LOK (the lunar mission Soyuz) for Earth orbital testing. Mostly the same vehicle, it lacked the larger antenna needed to communicate at lunar distance. The early Soyuz models also sported an external toroidal fuel tank surrounding the engines and meant to store extra propellant for lunar flights, but it was left empty on Soyuz 1-9. After the spacecraft was converted to a space station ferry, the tank was removed.