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NASAs iodine vapor feed system is based on a mechanism that holds and maintains the solid iodine is contact with a heated surface, in this case the walls of the propellant tank. The mechanism provides a robust and reliable steady-state delivery of sublimated iodine vapor to the ion propulsion system by ensuring good thermal contact between the solid iodine and the tank walls. To date, the technology development effort includes extensive thermal, mechanical and flow modelling together with testing of components and subsystems required to feed iodine propellant to a 200-W Hall thruster. The feed system has been designed to use materials that are resistant to the highly-reactive nature of iodine propellant. Dynamic modeling indicates that the feed system tubing can be built is such a way as to reduce vibrationally-induced stresses that occur during launch. Thermal modeling has been performed to demonstrate that the feed system heater power levels are sufficient to heat the tank and propellant lines to operating temperatures, and sublime the iodine in the storage tank to supply propellant for reliable and long-term operation.

This drain system, originally created to increase safety in neutral buoyancy tanks, has a high potential for increasing safety and performance in any application using a recirculation system. As opposed to a traditional cover for a drainage system, this device is comprised of many long, narrow channels through which water can flow. The openings are configured in a way that there is never a suction force large enough to trap one or multiple human bodies. In addition, the channels are deep enough that hair or other objects cannot become entangled or knotted because they cannot reconnect once in the channel. The drain system can be patterned to suit any pool (or spa, tank, container, etc.), and it can be placed on the floor, walls, or both. The technology is suitable for mass production methods such as extruding or molding. Why It's Better: The NASA innovation combines many desirable safety features into one simple system. Along with the decreased risk of limb entrapment and entanglement, the drain system also does a more thorough job of mixing chemicals, which diminishes bacteria growth and decreases operating costs. The system requires no protrusive drain cover, thereby eliminating the risk of injury due to bodily contact with the drain.

The in situ inspection technology for additive manufacturing combines different types of cameras strategically placed around the part to monitor its properties during construction. The IR cameras collect accurate temperature data to validate thermal math models, while the visual cameras obtain highly detailed data at the exact location of the laser to build accurate, as-built geometric models. Furthermore, certain adopted techniques (e.g., single to grouped pixels comparison to avoid bad/biased pixels) reduce false positive readings. NASA has developed and tested prototypes in both laser-sintered plastic and metal processes. The technology detected errors due to stray powder sparking and material layer lifts. Furthermore, the technology has the potential to detect anomalies in the property profile that are caused by errors due to stress, power density issues, incomplete melting, voids, incomplete fill, and layer lift-up. Three-dimensional models of the printed parts were reconstructed using only the collected data, which demonstrates the success and potential of the technology to provide a deeper understanding of the laser-metal interactions. By monitoring the print, layer by layer, in real-time, users can pause the process and make corrections to the build as needed, reducing material, energy, and time wasted in nonconforming parts.

Friction plug welding is a process in which there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part to fill or repair a hole or join two pieces (functioning like a rivet). Learning from 1,500+ quality &#34known&#34 plug welds, NASA&#146s experts build a load curve that, when combined with the welders&#146 knowledge of strain size, predicts the properties of a plug weld. The software monitors load, spindle speed, torque, displacement speed and distance, and the material properties and dimensions of the sample. The software correlates changes in the process parameters to mechanical testing of ultimate tensile strength. The software works for several Aluminum alloys such as 2015, 2195, and 2219. NASA is using the technology in its current work for closing out the termination hole of some friction stir welds. FPW is also used for repairs and as a potential replacement for rivets.

Conventional neutron beam experiments demand high fluxes that can only be obtained at research facilities equipped with a reactor source and neutron optics. However, access to these facilities is limited. The NASA technology uses grazing incidence reflective optics to produce focused beams of neutrons (Figure 1) from compact commercially available sources, resulting in higher flux concentrations. Neutrons are doubly reflected off of a parabolic and hyperbolic mirror at a sufficiently small angle, creating neutron beams that are convergent, divergent, or parallel. Neutron flux can be increased by concentrically nesting mirrors with the same focal length and curvature, resulting in a convergence of multiple neutron beams at a single focal point. The improved flux from the compact source may be used for non-destructive testing, imaging, and materials analysis. The grazing incidence neutron optic mirrors are fabricated using an electroformed nickel replication technique developed by NASA and the Harvard-Smithsonian Center for Astrophysics (Figure 2). A machined aluminum mandrel is super-polished to a surface roughness of 3-4 angstroms root mean square and plated with layers of highly reflective nickel-cobalt alloy. Residual stresses that can cause mirror warping are eliminated by periodically reversing the anode and cathode polarity of the electroplating system, resulting in a deformation-free surface. The fabrication process has been used to produce 0.5 meter and 1.0 meter lenses.

Friction Pull Plug Welding (FPPW) is the process necessary to plug the hole that is left behind as a friction stir weld (FSW) joint is completed and the pin tool of the welder retracts from the joint. FPPW involves a small, rotating part (plug) being spun and simultaneously pulled (forged) into a hole in a larger part. Much work has been done to fully understand and characterize the process and its limitations. FPPW worked very well for building large rocket sections such as the circumferential welds of the upper stages of NASA's Ares rocket, and to repair the external tank. Engineers were challenged to adapt FPPW to accommodate the thicker plates new alloy combinations of the SLS. The new hybrid plug solves the issue of the plugs snapping due to the increase torsion and moment stresses when joining thicker plates. The new hybrid plug, with a steel shank, makes FPPW more practical and robust. The new plug has been used to make space-qualified parts at NASA, and the plug welds are as strong as initial welds.

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.

NASA's researchers have designed modular fixtures to address inefficiencies in time, labor, and material costs due to the need to fabricate unique, monolithic fixture bodies for different segments of the Space Launch System (SLS). Before NASA staff can configure and weld rocket sections, they must assemble modular tooling atop a large turntable with radial grooves. Supporting braces (tombstones) that form the base of the modular structure slide into radial grooves. Other extending, clamping, and joining fixtures can be variously connected to the base structure to provide circumferential support for producing conical and cylindrical structures. NASA has used the tooling to produce structures with diameters of up to 27 feet. Depending on the desired application, the base can be scaled to produce larger or smaller diameters, and the grooves can be arranged with a longitudinal arrangement for production of parts with bilateral symmetry. The development of these modular fixtures required an initial investment similar to that of a single project's tool design and fabrication costs. Once produced, only a fraction of that time/cost is required to begin all subsequent projects. NASA has used this new, adaptable tooling in the construction of several different rocket stages, proving its cost-saving capabilities.

Ultrasonic Stir Welding is a solid state stir welding process, meaning that the weld work piece does not melt during the welding process. The process uses a stir rod to stir the plasticized abutting surfaces of two pieces of metallic alloy that forms the weld joint. Heating is done using a specially designed induction coil. The control system has the capability to pulse the high-power ultrasonic (HPU) energy of the stir rod on and off at different rates from 1-second pulses to 60-millisecond pulses. This pulsing capability allows the stir rod to act as a mechanical device (moving and stirring plasticized nugget material) when the HPU energy is off, and allowing the energized stir rod to transfer HPU energy into the weld nugget (to reduce forces, increase stir rod life, etc.) when the HPU energy is on. The process can be used to join high-melting-temperature alloys such as titanium, Inconel, and steel.