Separation of a two-phase gas/liquid flow stream into the respective gas and liquid constituents with minimum or no carryover is a necessary and challenging requirement in space vehicle life support systems in a micro-gravity environment. This paper will describe testing of two types of Russian MIR water separators in a one-gravity environment at conditions typical of each separator's MIR operating envelope.Presently on MIR, two types of two-phase separator designs, a static separator design and a rotary separator design, are used in several applications. The static separator design is used in the potable water processor. In addition, static separators are used in a carbon dioxide reduction system which is under development for MIR. A rotary separator design is used in both the urine processor and the hygiene water processor systems. Hamilton Standard, in cooperation with NIICHIMMASH, the hardware manufacturer, conducted on-site performance testing of both types of separators when challenged with various inlet two-phase gas/liquid flow conditions. Testing of the rotary separator also included inlet flows with the various types of MIR and planned ISSA soaps.Performance test results of the two-phase separators will be presented and observed. The results show a wide range of applications for a given separator design.