Lightweight, High-Flow ‘Floating Seal’ Valve for Cryogenic Propellant Management on Spacecraft

Orbital refueling of cryogenic propellants is a key enabling technology that will extend the usable life of spacecraft around Earth and facilitate the next generation of advanced exploration missions. Propellant management on orbit requires advanced propellant tanks, liquid acquisition devices, propellant transfer pumps, space rated valves, and other subcomponents compatible with common propellants and designed for use at cryogenic temperatures. We are working to help meet this need by developing a space rated valve for cryogenic propellants. Our valve uses a floating seal to provide low flow restriction without the bulky housing typically required of valves with large orifices. Through separate effects testing we (1) selected a seal material, (2) refined our seal geometry, and (3) confirmed performance under cryogenic conditions. We designed and built a full prototype valve (including a spaceflight ready actuator) and demonstrated sealing performance over 220 mechanical cycles at temperatures between 20 K–300 K. Our technology meets or exceeds NASA’s requirements for high flow propellant transfer valves (0 external leakage, < 10 sccm internal leakage, and Cv > 200) in a package significantly lighter than commercial state of the art valves for ground based use. Future plans include further design updates to reduce volume, vibration testing to demonstrate launch survival, a full scale hydrogen flow testing for ultimate proof of concept for our technology.