In a propellant tank, which especially stores cryogenic propellants, for example a fuel or an oxidizer for a spacecraft, and which operates with a driving gas to drive or convey the propellant, the propellant is separated from the driving gas in a propellant extraction apparatus using sieves with hydrostatic forces and capillary forces. The extraction apparatus includes a refillable reservoir, which is mounted near the tank floor outside of the tank shell, and which is connected via plural holes with the interior of the propellant tank. The extraction apparatus includes a double-walled housing that is thermally insulated. Capillary plates and struts are inserted in an L-shape into the reservoir. To substantially prevent the penetration of gas out of the propellant line, a cylinder-shaped pleated sieve is mounted at the end of the propellant line.