increased if the construction of the hermetizing locks of the hatches permit their disassembly if there is a failure of the main mechanism. Chapter 3 Issues Concerning the Construction of Docking Devices 3.1. Requirements of the Construction of Docking Devices. General Design Considerations Docking devices, like other systems of space technology, should satisfy general technical requirements imposed by flight on a rocket booster and in space. Detailed requirements are usually introduced in the technical assignment, the basic document used in the development of the docking device. Requirements for reliability and low construction mass are contradictory. To fulfill these requirements, the following are usually necessary: accurate consideration of external loads; careful static and dynamic analysis; efficiency and stability of shock absorber characteristics; low values and stability of the connection forces during docking, and disengagement during undocking for connectors and other elements; low friction in moving elements and high efficiency of mechanisms; reasonable force developed by the drives, the stability of these forces (small scatter and change in use); reasonable values of the safety and durability coefficients. For force and durability calculations the following basic cases of loading of the docking device are considered: shock absorption before and after linkage; coupling by the docking mechanism drive; coupling by the locks of the docking frame; loading by internal pressure before docking; loading of the joint and other elements by internal pressure and external loads; undocking (the operation of the locks and separation of the spacecraft). Tn the selection of durability norms, one considers the specific requirements on the docking device (the presence of a crew on the spacecraft, hermeticity, etc.). Tn development of the APDAs, for example, a safety coefficient kg = 1.5 was
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