chosen does not always unambiguously define the type of construction elements to be used. The principal design lays the foundation for the capabilities of the docking device, the foundation of reliability, technical and use properties; to a significant degree this scheme defines all further construction. Relow we mainly examine the principal schemes of two types of docking devices which form an accurate and rigid joint (the “rod and cone” and peripheral devices). The analysis of the created and developed docking mechanisms shows that their structure mainly corresponds to that described in section 1.2. The bearing base of the assembly is the hull, on which two main groups of mechanisms are installed: those which provide for docking and undocking, and elements to carry out additional functions. An analysis of the structure is decisive in the examination of the most important characteristics of the docking device: its weight and reliability. The composition of these groups depends primarily on the requirements made on the docking device. In turn the content depends substantial on the complexity and weight of the structure (Table 2.1). The data presented in the table shows that the mass of peripheral docking mechanisms is significantly larger than the mechanisms of the rod and cone type docking device. This is mainly due to the large size of the buffer, the larger number of rods and other elements of the docking mechanism. A completely passive docking assembly has the minimal mass, for example, the passive docking assembly for the Apollo lunar module. The content depends on the degree of redundancy of mechanisms and elements. The mass of the docking device is also determined by various other qualitative and quantitative requirements, for example, on hermeticity, the bearing capacity, rigidity, and the main dimensions. The entire construction may differ substantially depending on the degree of efficiency and the care taken in the design, the materials used and the technology. For example, in the initial stages of the creation of the Apollo APDA strict weight economy was not observed, as a result its mass, even without the tunnel hatch, which has a separate hermetic hull, was 1.7 times larger than the Soyuz APDA. The described approach to the analysis of the weight of the docking device is especially effective when applied to androgynous peripheral devices. The great weight of the APDAs compared to rod and cone type docking assemblies is a significant drawback restricting its further use. Analysis of the structure and a comparison based on Table 2.1 shows which elements have “excess” weight concentrated in them, and what must be done to lighten the peripheral structures. Tn
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