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Soyuz 7K-OK was the first generation of Soyuz spacecraft in use from 1967 to 1971.[1] This first generation was used for the first ferry flights to the Salyut space station program; Soyuz spacecraft in their current generation are still in use to ferry crew to and from the ISS.

Soyuz 7K-OK
Soyuz 7K-OK(A) drawing.png
Soyuz 7K-OK(A) spacecraft with an active docking unit
Country of origin Soviet Union
OperatorSoviet space program
ApplicationsCarry three cosmonauts to orbit and back
RegimeLow Earth orbit
StatusNo longer in service
First launchKosmos 133, 1966
Last launchSoyuz 9, 1970
Related spacecraft
Derived fromSoyuz-A (concept only)
DerivativesSoyuz 7K-OKS (Salyut 1 ferry)

Soyuz 7K-L1[citation needed] (lunar) Soyuz 7K-LOK[citation needed] (lunar)

Soyuz 7K-T (successor)
Soyuz family tree: Proposed Soyuz models in white, models that flew in blue and lunar models in green.[citation needed]

This generation is notable for the only fatalities of the Soyuz programme As of 2019, with Soyuz 1 in 1967 (sole crew-member killed by parachute failure) and Soyuz 11 in 1971 (crew killed by depressurization 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.

Soyuz 7K-OK spacecraft had a "probe and drogue" docking mechanism to connect with other spacecraft in orbit, in order to gather engineering data as a preparation for the Soviet space station program. There were two variants of Soyuz 7K-OK: Soyuz 7K-OK(A) featuring an active "probe" docking port, and Soyuz 7K-OK(P) featuring a passive "drogue" docking target. The docking mechanisms of 7K-OK and 7K-LOK did not allow internal transfer (this feature was added on the 7K-OKS version), thus cosmonauts had to spacewalk between docked modules. This procedure was conducted successfully on the joint Soyuz 4 and Soyuz 5 missions, where Aleksei Yeliseyev and Yevgeny Khrunov transferred from their Soyuz 5 to the Soyuz 4 craft.

The first unmanned test of this version was Kosmos 133, launched on November 28, 1966.


Soyuz 7K-OKSEdit

The last two Soyuz space craft of this series were of the designation Soyuz 7K-OKS. In contrast to Soyuz 7K-OK, which docking mechanism lacked a hatch for internal crew transfer, the Soyuz 7K-OKS spacecraft were modified to utilize the new SSVP docking system that allowed internal crew transfer – this was performed for the first time with the manning of the Salyut 1 space station by Soyuz 11. The SSVP docking adapter is still in use today on the ISS.

Unmanned and test missionsEdit

Manned missionsEdit

  • Soyuz 1, the first manned Soyuz flight, commander and sole crew-member killed on re-entry
  • Soyuz 3
  • Soyuz 4 and Soyuz 5, the first manned docking and first crew transfer in the history of spaceflight
  • Soyuz 6
  • Soyuz 7 and Soyuz 8: Intended docking, to be filmed by Soyuz 6 crew – docking failed due to malfunction
  • Soyuz 9
  • Soyuz 10 (Soyuz 7K-OKS), Salyut 1 ferry, the first docking to a space station in the history of spaceflight
  • Soyuz 11 (Soyuz 7K-OKS), Salyut 1 ferry, the first manning of a space station in the history of spaceflight – crew killed on re-entry

External linksEdit


  1. ^ Portree, David (March 1995). "Mir Hardware Heritage" (PDF). NASA. Archived from the original (PDF) on 3 August 2009. Retrieved 24 August 2012.