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The Rotational Tension Element Damper (RTED) uses a controlled tension line, backed by hydraulics, to damp large displacements in large structures. NASA built RTED prototypes that have been successfully tested on a 170-foot long wind turbine blade in test beds at the University of Maine. In this case, the RTED device damps the vibration of the large, tall turbine blades relative to a stationary anchor structure on the ground using a line and spring coupled to both the blade and the anchor, and controlled by a spool fitted with a one-way clutch. When force is applied, from heavy wind for example, the resulting movement of the tall structure triggers the necessary tension and compression cycles in the system to engage the rotating damper. The reaction force interferes with the rotation speed of the spool and disrupts and damps the vibration in the tall structure. The figure below shows test data for the RTED used on the wind turbine.

Additive manufacturing methods (e.g. Laser Metal Sintering) are used to integrally fabricate a tuned-mass vibration absorber inside a turbine blade. The design approach uses an internal column manufactured as part of the blade that is optimized such that the dynamics of the blade damper system are rearranged and reduced according to the well-known science of tuned mass-absorption (TMA). The TMA concept has been implemented successfully in applications ranging from skyscrapers to liquid oxygen tanks for space vehicles. Indeed, this theory has been conceptually applied to bladed-disk vibration, but a practical design has not previously been reported. The NASA innovation addresses another important challenge for turbine blade vibration damper designs. All existing blade damper solutions are essentially incapable of being reliably predicted, so an expensive post-design test program must be performed to validate the expected response. Even then, the actual magnitude of the response reduction under actual hot fire conditions may never be known. The dynamic response of this tuned-mass-absorber design is both substantial and can be analytically predicted with high confidence, and thus the response can be incorporated fully into the up-front design process.

The NASA receiver is specifically designed for use in coherent LiDAR systems that leverage high-energy (i.e., > 1mJ) fiber laser transmitters. Within the receiver, an outgoing laser pulse from the high-energy laser transmitter is precisely manipulated using robust dielectric and coated optics including mirrors, waveplates, a beamsplitter, and a beam expander. These components appropriately condition and direct the high-energy light out of the instrument to the atmosphere for measurement. Lower energy atmospheric backscatter that returns to the system is captured, manipulated, and directed using several of the previously noted high-energy compatible bulk optics. The beam splitter redirects the return signal to mirrors and a waveplate ahead of a mode-matching component that couples the signal to a fiber optic cable that is routed to a 50/50 coupler photodetector. The receiver’s hybrid optic design capitalizes on the advantages of both high-energy bulk optics and fiber optics, resulting in order-of-magnitude enhancement in performance, enhanced functionality, and increased flexibility that make it ideal for long-distance or low-backscatter LiDAR applications. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale.

NASA's ODS-MEA maintains properties up to 1100°C and is not susceptible to deleterious phase changes when exposed to extreme temperatures, an issue ubiquitous to Ni- based superalloys such as Inconel-625 and Inconel-718. Yttria particles are dispersed throughout the alloy to maximize strength and creep resistance at high temperatures using a novel fabrication technique. This technique employs an acoustic mixer to stir nano-scale Yttria oxide powder within a metallic matrix powder, creating a film of Yttria surrounding the larger metallic powder particles. Solid components are then produced from this mixture via SLM, during which the laser disperses the Yttria particles throughout the microstructure. Ultimately, the process eliminates the many expensive and time-consuming steps in the production of ODS alloys via traditional mechanical alloying. NASA's process has been shown to fabricate components with 10x improvement in creep rupture life at 1100°C and provides a 30% increase in strength over what is currently possible with 3D printed parts. The new ODS-MEA composition may find applications where ODS alloys are currently used (e.g., those involving extreme thermal environments). Applications may also include areas where such properties are desirable but the resource-intensive nature and/or inability to produce highly complex geometries via conventional processes ultimately renders their use uneconomical or infeasible. Such uses include gas turbine components (for which increasing inlet temperature enables improved efficiency) for power generation, propulsion (rockets, jet engines, etc.), industrial processes, nuclear energy applications, and sample preparation equipment in the mining and cement production industries, among many others.

The core “Strayton” generator technology consists of a gas turbine engine with short, axial pistons installed inside the hollow turbine shaft. These pistons form a Stirling engine that cycles via thermo-acoustic waves, transferring heat from the turbine blades to the compressor stage, which improves overall engine performance. Power to an alternator is, thus, delivered from both turbine shaft rotation and the oscillation of the internal pistons. This synergistic relationship is markedly enhanced in a closed-cycle system, where the sealed turbine engine recirculates a working fluid heated via an external source, such as a hydrogen fuel cell and combustor. This system supports higher compression ratios, reduces the turbine diameter to less than 4”, and eliminates the need for large recuperators. Operational efficiency is projected to extend into the low temperature range (750° C), reducing the need for advanced materials and providing cleaner combustion for hydrogen-based applications. Pressurized, inert working fluids also replace mechanical bearings and gearboxes, enabling years of maintenance-free operation. The fuel cell and Stirling cycle produce 10% of the total system energy, while the Brayton cycle produces 90%. Other external heat sources could include nuclear, solar, or biogas. Conservative estimates for the hydrogen fuel-cell configuration lifetime are in the 100,000 hour range.