The Universal Docking Module (UDM) (Russian: Универсальный стыковочный модуль), was a planned Russian docking module for the International Space Station, to be jointly built by RKK Energia and Khrunichev.
The Prichal nodal addition to the Nauka laboratory, the eventual form of the FGB-2 design upon which the UDM was based, grew out of this proposal.
[1] The original design resembled Zarya but was larger.
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 and Cargo Module, later named Rassvet.