Image Number 5 for United States Patent #7621291.
A fuel tank of a spacecraft stores a liquid fuel and a pressurized propellant gas that drives the fuel out of the tank though a fuel extraction arrangement including a reservoir or fuel collection container and a tank outlet. A spiraling or J-shaped or hook-shaped fuel collection channel and plural obliquely sloping fuel flow channels connect the fuel collection container to an outlet pipe of the tank outlet. The channels are configured, dimensioned, oriented and arranged to ensure that fuel will be retained in the outlet pipe without leaking back into the fuel tank, even when the tank is oriented horizontally and has a low tank filling level. These structures produce a capillary pumping effect and use the surface tension to separate the fuel from the propellant gas, and allow the inner space of the collection container to be completely filled with liquid fuel.