A serviceable system for handling fluids in microgravity includes supply reservoirs to hold a supply fluid for a process, a fluid processing unit to perform the process and a collection reservoir to collect a fluid from the fluid processing unit. Each supply reservoirs is provided with a supply valve assembly of valves and conduits, and at least one external conduit that is connectable to an external fluid source or to an external suction source. The supply valve assembly is configured to enable individually: flow of the supply fluid from the supply reservoir to the fluid processing unit, flow of a fluid into the supply reservoir from the external conduit; withdrawal of fluid from supply reservoir to the external conduit, and flow of fluid from the external conduit to the fluid processing unit.