A Zero-Gravity Thermodynamic Vent System for the Shuttle/Centaur Hydrogen Tank

A thermodynamic vent system (TVS) is being designed and built by Sundstrand for the Shuttle/Centaur LH₂ tank based on concepts developed under previous General Dynamics Convair (GDC)/NASA studies and laboratory demonstrations. The TVS performs the function of controlling pressure in the liquid hydrogen tank during periods of low-gravity storage and assures venting of vapor from the cryogenic propellant tank without disturbing normal Shuttle operation. Major components of the TVS are a swirl flow heat exchanger, an electric mixer pump with fully redundant thermally conditioned electronic inverter, and parallel redundant throttling regulators with filters and shutoff valves.