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.
Mir Hardware Heritage. NASA Reference Publication 1357 (March 1995).
David S. F. Portree / NASA