A cabin pressure vent and emergency relief valve subassembly (VRV) was developed for Boeing Defense and Space as part of the International Space Station. Functional enhancements were made for Mitsubishi Heavy Industries, Ltd., to meet the unique requirements of the Japanese Experiment Module.
The VRV provides nine distinct functions or features, including redundant closure elements, de-berthing capability, maximized resistance to ice collection during cabin depressurization, electronic flow modulation, and manual operation capabilities. It is designed as an orbital replacement unit with a 10-year on-orbit lifetime.
This paper provides an overview of the multiple system requirements, the principles involved, and concept validation tests which drove the final design to meet the challenging requirements of a 10-year operational valve with exceptional leakage control.