Development and Optimization of a Tridyne Pressurization System for Pressure Fed Launch Vehicles

摘要

Over the recent years, Microcosm has been pursuing the development of a Tridyne-based pressurization system and its implementation in the Scorpius family of launch vehicles to obtain substantial gain in payload to orbit. This technology program was initiated with an IR&D program and matured with contracts from the National Reconnaissance Office (NRO), and the Air Force Research Laboratory (AFRL). The Tridyne pressurization system functions by mixing small amounts of hydrogen and oxygen with the pressurant gas (typically helium). When the mixture is passed through a catalyst bed, the hydrogen and oxygen react to produce heat. The result is hot pressurant gas, with a small amount of water vapor remaining from the combustion process. The implementation scheme developed for the Scorpius family of launch vehicles involves returning some of the heat to the Tridyne mixture in the pressurant tank by means of an internal heat exchanger. This offsets the expansion cooling such that the temperature of the pressurant actually rises as the pressurant is used. The remaining energy is used to elevate the temperature of the gas delivered to the propellant tanks to near the maximum allowable operating temperature of the downstream components (typically about 200 to 250 deg F) such as the regulator and the composite over-wrapped propellant tanks. The result of heating the helium in this way was shown to reduce the mass and volume of required helium and the associated tankage by nearly 50%, resulting in substantial payload gain.