Universal Docking Module
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Universal Docking Module - The nodal module grew from the proposed Universal Docking Module (UDM) (Russian: Универсальный стыковочный модуль), which was a planned Russian docking module for the International Space Station, to be jointly built by RKK Energia and Khrunichev.
The original design resembled the Functional Cargo Block albeit larger, and would have it docked to the nadir (Earth-facing) Zvezda service module docking port, and have four docking ports to accommodate the two Russian Research Modules and the SO2 docking compartment.
Because the SO2 and a Research Module were cancelled due to lack of funds, this module was also cancelled. The one remaining Research Module was then scheduled to be fitted to the open docking port on Zvezda. Later it was also cancelled and that port was allocated to the Docking Cargo Module. DCM scheduled location was later moved to Zarya.