In a dielectrophoretic, zero-gravity liquid expulsion system, the polarization forces serve to 1) define a portion of the tank volume where the liquid is preferentially oriented and 2) provide a channeling mechanism by which the liquid can be withdrawn from that region through the agency of external pressure sources. In the relatively lightweight concept described, high-voltage ribbon electrodes deployed along the tank wall form conduits with the wall through which liquid contacting the ribbon at any point is communicated to the drain. The side walls of these conduits are electromechanical and depend for their rigidity on the electrohydrodynamic bang-bang interaction between the liquid interfaces and the strong fringing field gradient at the ribbon edges. A steady-flow design model relates electrode geometry and voltage to fluid properties and withdrawal rate. A dynamic model describes flow criticality effects and the consequences of perturbations in pressure. Electrohydrodynamic surface waves, which play a role in dielectrophoretic pipes similar to that of gravity waves in ordinary free-channel flows, are described and verified experimentally. Experiments demonstrate the significance of the steady-flow and dynamic models, and an example illustrates the design of typical expulsion systems for cryogenic hydrogen and oxygen.