Abstract: A liquid-vapor separation system for use in a zero gravity environment for transferring and storing fluids, and particularly fluids that are primarily liquid, such as propellants, reactants and coolants, among others, has a low supply tank pressure and low pressurant gas requirement, which results in maximized capacity, reduced system weight and reduced cost. The temperature of a container provided as part of the present invention is decreased below the freezing point of residual liquid within the container. Non-compressible gas is thereafter vented and the liquid raised to liquid temperature. Gaseous contaminants are thereby vented and subsequent filling of the container is thereby maximized.

Abstract: A system for providing cryogenic sub-critical liquid oxygen and liquid hydrogen to storage tanks and payloads contained inside the payload bay of a space vehicle is described. The system provides for transferring cryogenic fluid from a supercritical storage tank to a subcritical storage tank or payload in a zero-g environment, wherein the H2 and O2 ignition hazard has been eliminated due to the low vacuum pressure operating environment. The system includes an external heat exchanger, for example, a parallel flow concentric tube design, and a temperature control system for re-condensing the two-phase transfer fluid expelled from the supercritical storage system into a single phase, sub-cooled cryogenic fluid which is then introduced into and stored within the subcritical storage tank.