Cooperative Service Valve for In-orbit Cooperative Satellite Fueling

The Miniature Separable Fill & Drain Valve consists of two halves (ground and flight). The flight half is attached to the vehicle (i.e., CubeSat), and the ground half can be inserted into the vehicle in the same port as the flight half, connecting the two halves together. In normal state, the flight half seals the flow path. When the ground half is connected, the flow path is opened, allowing connected ground support equipment to supply fluid through the valve. The valve is manually operated. There are redundant seals to eliminate leakage around the valve, including NASA's previously-patented Low-Cost, Long Lasting Valve Seal design (Patent No. 10,197,165; see MFS-TOPS-71 in the Links section of this flyer for more information) on the flight half. This eliminates the need for a swaged assembly process and the additional hardware and equipment that are typically required in conventional, elastomeric valve seat installations. The design also includes a cap for the flight half to ensure there is no leakage in flight configuration. The Miniature Separable Fill & Drain Valve has been prototyped and provides valuable benefits for CubeSat applications. The valve could also have applications in the industrial processing industry where low flow devices are commonly used. The design is also scalable to larger applications where the removal of the actuation device would be desired.

NASA's technique simplifies the seat installation process by requiring less installation equipment, eliminating the need for unnecessary apparatus such as fasteners and retainers. Multiple seals can be installed simultaneously, saving both time and money. NASA has tested the long-term performance of a solenoid actuated valve with a seat that was fitted using the new installation technique. The valve was fabricated and tested to determine high-cycle and internal leakage performance for an inductive pulsed plasma thruster (IPPT) application for in-space propulsion. The valve demonstrated the capability to throttle the gas flow rate while maintaining low leakage rates of less than 10-3 standard cubic centimeters per second (sccss) of helium (He) at the beginning of the valves lifetime. The IPPT solenoid actuated valve test successfully reached 1 million cycles with desirable leakage performance, which is beyond traditional solenoid valve applications requirements. Future design iterations can further enhance the valve's life span and performance. The seat seal installation method is most applicable to small valve instruments that have a small orifice of 0.5 inches or less.

NASA's Debris-Tolerant Valve is designed for use in machines/environments with a large quantity of airborne dust or other contaminants. Valves subjected to airborne contaminants tend to have limited lifetime due to damaged seals, bearings, and other internal components. The Debris-Tolerant Valve design addresses this problem with four core improvements over existing commercial valves that are typically used in dusty or debris-laden processes: (1) a new cylinder design that substantially decreases dust collection within the valve; (2) a rotational valve design that minimizes grinding and packing experienced by the standard ball valve; (3) the use of elastomeric seals rather than the Teflon-based seals used in existing valves which are prone to scratching and subsequent leakage; and (4) a bleed port for fluid intake that allows pressure to build slowly in the valve and eliminates the stirring of dust commonly caused by rapid inflow of air in existing valves. The operational lifetime of NASA's Debris-Tolerant Valve exceeds the lifetime of a standard commercial valve and the existing selector valve used on the ISS by 12X and 6X, respectively. NASA's valve design has fewer parts than existing valves and could be disassembled without tools, enabling easier servicing and maintenance. The Debris-Tolerant Valve is only about one-seventh (1/7) the cost of the existing ISS selector valve.

Space and ground launch support related hardware often operate under extreme pressure, temperature, and corrosive conditions. When dealing with this type of equipment, it is frequently necessary to run wiring, tubes, or fibers through a barrier separating one process from another with one or both operating in extreme environments. Feedthroughs used to route the wiring, tubes, or fibers through these barriers must meet stringent sealing and leak tightness requirements. This affordable NASA feedthrough meets or exceeds all sealing and leak requirements utilizing easy-to-assemble commercial-off-the-shelf hardware with no special tooling. The feedthrough is a fully reconfigurable design; however, it can also be produced as a permanent device. Thermal cycling and helium mass spectrometer leak testing under extreme conditions of full cryogenic temperatures and high vacuum have proven the sealing capability of this feedthrough with or without potting (epoxy fill) on the ends. Packing material disks used in the construction of the device can be replaced as needed for rebuilding a given feedthrough for another job or a different set of feeds if potting is not used for the original feedthrough build. (Potting on one or both sides of the sleeve provides double or triple leak sealing protection). Variable Compression Ratio (VCR) connectors were adapted for the pressure seal on the feedthrough; however, any commercial connector can be similarly adapted. The design can easily be scaled up to larger (2" diameter) and even very large (12" or more) sizes.

The VARR valve has been designed to provide a variable-size aperture that proportionately changes in relation to gas flow demand. When the pressure delta between two chambers is low, the effective aperture cross-sectional area is small, while at high delta pressure the effective aperture cross-sectional area is large. This variable aperture prevents overly restricted gas flow. As shown in the drawing below, gas flow through the VARR valve is not one way. Gas flow can traverse through the device in a back-and-forth reversing flow manner or be used in a single flow direction manner. The contour shapes and spacing can be set to create a linear delta pressure vs. flow rate or other pressure functions not enabled by current standard orifices. Also, the device can be tuned to operate as a flow meter over an extremely large flow range as compared to fixed-orifice meters. As a meter, the device is capable of matching or exceeding the turbine meter ratio of 150:1 without possessing the many mechanical failure modes associated with turbine bearings, blades, and friction, etc.