Abstract: A liquid propellant supply device for satellites comprises an inlet pipe connected to a source of pressurizing gas, an outlet pipe connected to a propellant distribution manifold and a main storage tank connected at an inlet orifice to the inlet pipe and at an outlet orifice to the outlet pipe. The main storage tank contains a capillary action propellant retention device between the interior of the main storage tank and the outlet pipe. The device further comprises, on the outlet pipe, starting from the main storage tank, a gas test device adapted to detect the presence in the outlet pipe of a significant quantity of gas followed by an auxiliary storage tank substantially smaller than the main storage tank and including a second capillary action propellant retention device separating the interior of the auxiliary storage tank and the distribution manifold.