Abstract: An improved and simplified system for densifying a cryogenic liquid for space vehicles is provided, which includes a heat exchanger having heat exchange tubes therein for receiving a flow of liquid from a storage tank, for example a liquid propellant in a vehicle storage tank. The heat exchanger is filled around the exchange tubes with a two-component bath, the volume of a primary component substantially exceeding the volume of a secondary component. The secondary component has a boiling temperature that is lower than the boiling temperature of the primary component, and both are lower than the boiling temperature of the cryogenic liquid. In one example, the liquid to be densified is oxygen, the primary component is liquid nitrogen, and a secondary component is liquid hydrogen. The secondary component is preferably injected into the heat exchanger in separate flows to prevent localized freezing of the first component.

Abstract: An improved and simplified system for densifying a cryogenic liquid for space vehicles is provided, which includes a heat exchanger having heat exchange tubes therein for receiving a flow of liquid from a storage tank, for example a liquid propellant in a vehicle storage tank. The heat exchanger is filled around the exchange tubes with a two-component bath, the volume of a primary component substantially exceeding the volume of a secondary component. The secondary component has a boiling temperature that is lower than the boiling temperature of the primary component, and both are lower than the boiling temperature of the cryogenic liquid. In one example, the liquid to be densified is oxygen, the primary component is liquid nitrogen, and a secondary component is liquid hydrogen. The secondary component is preferably injected into the heat exchanger in separate flows to prevent localized freezing of the first component.