Next Generation Propellant Isolation Valve Design and Development

The opportunity to design and develop a new small propulsion propellant isolation valve carries with it a heavy responsibility to the heritage product success and user community expectations. For the 0.1 to 1.0 lbf monopropellant thruster valve range, the incumbent design has successfully serviced the industry for a time span approaching 40 years . This heritage design has been a part of every NASA discovery mission and nearly every launch vehicle. There are more of these propellant valves orbiting Earth than there are on Earth’s surface. The heritage design is based on a sliding plunger assembly. This sliding design has a limited dry cycle life capability. Sliding friction between the plunger and guiding bore, which generates particulate, limits the dry cycle life capability. The generation of particulate is considered an undesirable feature and has the potential of degrading seal integrity. Eliminating the sliding friction by applying a suspended armature style solenoid provides a dramatic improvement over the heritage design. The new design eliminates the sliding interaction and the associated generation of particulate. A thorough and conservative design is built and tested to the current environmental loads. The design modeling methodology is validated by test. Additional testing to establish actual boundaries increases the confidence level for the change to a new design. Concurrent design activities addressed manufacturing, assembly, and test interests to optimize the configuration in support of a dramatically reduced lead-time and to control associated costs.