locks of the docking frame was as follows: Opening of the joint could be caused by: destruction of parts; rotation of the eccentric shafts; rotation of the active clamps relative to the shafts; issuing of random or spontaneous commands. Tn order to eliminate breakdowns, the following measures were taken: a lock construction was used in which durability of only the minimal number of elements is critical; materials are used which are qualified for space conditions; the durability of critical parts is increased (for the tensile limit); springs which regulate force in each lock were installed. Spontaneous rotation of the eccentric shafts is prevented by: friction of the brushes of the collector electrical motors; the stoppage coupling of the drive; the displacement of shafts in the tightened state by from the dead position. To eliminate rotation of the active clamps with disengagement of the contacting surfaces, the clamps are profiled such that the force of compression creates a momentum which closes the clamp. The stoppage plank prevents rotation in the tightened position. Random or spontaneous actuation of the drives is eliminated by the introduction of blocking on the issuing of commands both from the spacecraft and from Earth. Also a number of design, construction, and procedural methods are used (two-drive, three-channel control circuits, high quality insulation, careful testing, etc.). Actually, to send voltage to the electrical engine one must issue three commands in a specific sequence: 1) turn on supply; 2) remove blocking; 3) send voltage to electrical engine. The state of the control circuits are monitored on the spacecraft and in the Flight Control Center during operation. Similar measures are taken to eliminate random issuing of commands or spontaneous actuation of the pyrotechnic bolts for back-up undocking [4]. 3.4. Construction of the Docking Mechanisms 3.4.1. “Rod and Cone” Type Docking Mechanisms The rod of the docking mechanism of this type has a substantial course (tens of millimeters). Thus the rods are installed on long-course guides, the construction
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