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Figure 1-8. Original Soyuz probe and drogue docking system. The active unit
(right) consisted of a probe and latches; the passive unit, a receiving cone,
socket, and catches. The passive unit’s frustum was longer than the active unit’s
because it was designed to accept the probe. The probe acted as a shock absorber.
Its tip contained sensors which registered contact with the cone, disabled the
active craft’s control system, and fired thrusters on the active craft to force
the spacecraft together. The probe entered the socket at the apex of the cone,
whereupon catches and a restraining ring locked it into place. Plugs and sockets
in the rims of the docking units then established electrical and intercom
connections between the spacecraft.[1]

1.3.1 Original Soyuz Specifications

Launch weight .......................................... about 6600 kg
Launch vehicle ......................................... Soyuz
Length ..................................................... about 9 m
Span across solar arrays .......................... 10 m
Diameter of habitable modules ................... 2.2 m
Maximum diameter ................................... 2.72 m
Habitable volume ...................................... 10 m3
Number of crew ........................................ 1-3


1.3.2 Original Soyuz Notable Features

  • Launched on a Soyuz rocket (figure 1-7). All Soyuz variants except the L1 and L2 have launched on this rocket.
  • Except during EVA, its crew did not wear space suits.
  • Made no provision for internal crew transfer after docking. Crew transfer involved EVA between two docked craft.
  • Used a simple probe and drogue docking system (figure 1-8).
  • Had handrails on the outside of its orbital module to facilitate external crew transfer after docking.
  • Orbital module served as an airlock for external crew transfer; it also served as a laboratory, a storage compartment, and living space for the crew.
  • Carried a toroidal tank in its aft skirt. This was an electronics compartment or propellant tank (it was never flown carrying propellants).
  1. V. S. Syromiatnikov, “Docking of Spacecrafts and Modules in the Mir Orbital Station Program,” Mir Space Station Symposium: A Technical Overview, July 27-28, 1993.