Progress on a small multi-cycling cryogenic fluid flow valve Original Research Article

Mission Research Corporation (MRC) in cooperation with the Jet Propulsion Laboratory (JPL) has developed a new small remote-controlled fluid valve. The motivation for developing this valve came from the requirements of a future International Space Station experiment called Microgravity Scaling Theory Experiment (MISTE). This experiment requires an in situ, low-temperature operated, fluid valve that can be open/closed over 50 times during a 4.5 month flight. The successful operation of MISTE and other space-based and ground-based laboratory experiments now in development will require reliable cryogenic fluid valves that are remotely operated, helium leak tight, non-magnetic, very low power, and which have a small dead volume. The new valve is normally closed and requires fluid actuation at a pressure of approximately 600 kPa to open. The heart of the valve design is found in the configuration of the valve seat and sealing poppet. The design of these two surfaces was derived from work performed previously during a five year development program for a larger MRC remote-controlled, cryogenic fluid flow control valve. More than 50 of the larger valves have been produced and delivered for space flight applications. The new small valve has only three moving parts, which move less than 0.012 cm when the valve fully opens or closes. The bearing surfaces in the valve operating mechanism are all flexure (except for the valve poppet) and thus the valve is expected to have a lifetime of thousands of open/close cycles. The materials and processes used to fabricate the new valve have been flight certified. Results from the first extensively tested prototype show repeatable behavior with a leak rate of typically 3×10−8 scc/s after the first open/close cycle at 4.2 K, rising to about 10−6 scc/s after 100 cycles. Further tests and minor modifications are expected to improve the performance.