A system for transferring a fluid from a first spacecraft to a second spacecraft. The first spacecraft includes a fluid transfer system comprising: a pressurant supply system, a first fluid tank to store a fluid to be transferred, one or more transfer feedlines to provide fluidic connection between the first fluid tank and the second spacecraft, a connector for connecting the first spacecraft to the second spacecraft, an accumulator tank comprising a first portion connected to the pressurant supply system, a second portion configured in fluidic communication with the one or more transfer feedlines, and a flexible separator to separate the first portion and the second portion. The pressurant supply system supplies pressurant gas to the first fluid tank for pressurising the first fluid tank and to supply pressurant gas to the first portion of the accumulator tank for pressurising the first portion of the accumulator tank.