Search

Used for propelling Earth-orbiting satellites and deep-space robotic vehicles, the HET gets its name because it traps electrons with an intense radial magnetic field in an azimuthal Hall current moving around the circumference of an annular ceramic channel. The electrons in the circulating Hall current ionize the onboard propellant - the inert gas xenon - and create an ionized plasma. The xenon plasma is then accelerated axially, via an applied electric field along the coaxial channel, to an exit velocity of up to 65,000 miles per hour to produce thrust. The interaction of the accelerated plasma and the downstream edge of the channel, where the plasma is the most energetic, results in erosion of the surrounding magnetic system used to generate the plasma. One of NASA Glenn's novel designs relies on an azimuthally symmetric configuration that minimizes radial magnetic fields at the discharge chamber walls. This configuration completely shields the walls of the discharge chamber from the high-energy plasma ions. With regard to the discharge-channel-wall replacement innovation, an actuator can be configured to extend the discharge chamber along the centerline axis. The actuator can be either mechanical or programmable. In either case, the sleeve can be extended while an upstream portion of the discharge chamber remains stationary, thereby preventing plasma exposure. These novel designs increase the efficiency and extend the lifetime of the HET to five times that of unshielded thrusters, enabling a new era of space missions.

Traditional cryogenic cooling methods, such as pulse-tube and reverse Brayton cryocoolers, are constrained by moving parts, high mass, and limited cooling capacity. Their mechanical complexity increases maintenance needs and reduces reliability, while their bulk adds significant weight penalties to mobile platforms. Although these systems can achieve kilowatt-scale cooling, they struggle to maintain stable, efficient performance under the continuous, high thermal loads required for megawatt-scale superconducting propulsion. The CryoQuad was developed specifically to address these shortcomings, delivering a lighter, more reliable, and higher-capacity solution tailored for superconducting electric propulsion systems. The novel design utilizes four thermoacoustic Stirling heat engines arranged a quarter wavelength apart in a quad loop configuration. This configuration – wherein each engine has high-power acoustic energy pulled off via power pulse-tube coolers – allows for rapid acoustic wave amplification without moving parts (e.g., pistons, turbines, pumps) or electricity. Importantly, the innovative design eliminates the need for large linear piston generators and large recuperator heat exchangers – two features common in megawatt-scale cryocooling pressure systems today – significantly reducing the overall system mass and complexity. While designed for use with liquid Helium, CryoQuad can utilize a variety of fluids depending on the required cryogenic temperatures. CryoQuad has the potential to be used in superconducting electric aircraft, other advanced propulsion systems, in-space cryogenic fluid management, cryosurgical cancer treatment probes, MRI systems, cryogenic cooling and packaging systems for superconducting electronics, space fuel depots, and other power applications. CryoQuad is available for patent licensing.

In applying PS400 using the plasma spray-coating process, a 0.010 inch layer is deposited onto a metal surface. This composite coating often includes a metallic-based binder, a metal-bonded hardener, a high-temperature lubricant, and/or a low- temperature lubricant. PS400's improved metallic-based binder alloy greatly increases the structural strength and durability of the composite with respect to the operating temperature and the bearing load, and provides superior dimensional stability. PS400's metal-bonded oxide hardening agent provides additional hardness, wear resistance, and thermal stability, while also exhibiting a low coefficient of friction when used in sliding contacts. It is also significantly less expensive in terms of both acquisition and grinding processes. Depending on the desired environment, high- and low-temperature lubricants may be added to the composite coating. The preferred high-temperature lubricant is a metal fluoride and the optional optional low-temperature lubricant is composed of metals, such as silver or copper, that are soft enough to provide lubrication at low temperature while maintaining oxidation resistance with a sufficiently high melting point. These qualities permit the materials to be used over a broad temperature range. Once the spray coating has been applied, the metal surface is ground and polished to produce a smooth, self-lubricating surface before use. Unlike some coatings that must be diamond-ground, PS400 is readily ground with a substantially less expensive abrasive, such as silicon carbide. This grinding process generally yields a coating thickness of 200 to 400 micrometers. In instances when a coating is not convenient or possible, powder metallurgy techniques using PM400 can be used to make freestanding self-lubricating components such as bushings and wear plates.

Originally developed to demonstrate a highly accurate, low-false-alarm, early fire detection system in space, this advanced technology level system utilizes a durable, low-cost, compact laser source and detector array, similar to CD/DVD player technology, to analyze the interaction of light with particles. The smart system is ideal for detecting a diverse range of particles found in pollution, emissions, fire and other atmospheric toxins while introducing a flexibility that enables its use in multiple environments, especially when coupled with UAVs or other remote platforms. The MPASS contains a number of features that allow users to make the most of its pioneering capabilities. The self-contained system is lightweight and has been miniaturized and packaged to easily fit into the palm of your hand. A USB port enables the system to be powered, configured, and accessed through its onboard central processing unit. The advanced graphical user interface, custom software, and optimized algorithm allows the user to select known properties when applicable, and to program the system for maximum performance. The dashboard also provides visual feedback through graphical displays, making it easy to analyze the data and make real-time decisions. The system is designed with Bluetooth expansion capability, adding flexibility and communication through potential custom cellular phone applications. Once programmed, the battery-powered wireless sensor system opens the door to monitoring remote areas and extreme environments never thought possible.

Current subcutaneous vessel imagers use large, multiple, and often separate assemblies with complicated optics to image subcutaneous structures as two-dimensional maps on a wide monitor, or as maps extracted by a computer and focused onto the skin by a video projection. The scattering of infrared light that takes place during this process produces images that are shadowy and distorted. By contrast, Glenn's innovative approach offers a relatively compact and inexpensive alternative to the conventional setup, while also producing clearer images that can be rendered in either two or three dimensions. Glenn's device uses off-the-shelf near-infrared technology that is not affected by melanin content and can also operate in dark environments. In Glenn's novel subcutaneous imager, a camera is configured to generate a video frame. Connected to the camera is a processor that receives the signal for the video frame and adjusts the thresholds for darkness and whiteness. The result is that the vein (or other subcutaneous structure) will show very dark, while other surrounding features (which would register as gray) become closer to white due to the heightened contrast between thresholds. With no interval of complex algorithms required, the image is presented in real-time on a display, yielding immediate results. Glenn's advanced technology also allows the operator to achieve increased depth perception through the synchronization of a pair of imaging devices. Additionally, the novel use of a virtual-reality headset affords a three-dimensional view of the field, thereby improving the visualization of veins. In short, Glenn's researchers have produced an inexpensive, lightweight, high-utility device for locating and identifying subcutaneous structures in patients.

NASA Glenn's durable, extreme-temperature, integrated circuit chips begin with the replacement of conventional silicon IC transistors with n-channel SiC junction field effect transistors (JFET) and resistors that can reliably function above 500°C. JFETs with the necessary high-temperature stability and electrical gain are fabricated from commercial 4H-SiC wafers with epilayers using dry etching and a self-aligned n-type ion implantation. An innovative circuit approach creates digital logic gates from these normally-on n-channel JFETs and resistors. Using two levels of 500°C durable metal to interconnect numerous SiC gates, complex circuits enabling a variety of control, operation and sensing functions for intelligent systems in harsh environments can be implemented in physically small chips. The challenge of getting electrical signals to and from the chip in a harsh environment is overcome by the use of the iridium interfacial stack (IrIS) that acts simultaneously as a bond metal and diffusion barrier, and can be used on an ohmic contact to the SiC. Combined with Glenn-developed high-temperature durable ceramic chip packaging and harsh environment sensor technology, this revolutionary durable integrated circuit technology is game changing for harsh-environment applications of all types.

In general, individual fuel cells produce relatively small electrical potentials, so fuel cells are "stacked" or placed in series (anode to cathode) to increase the combined voltage and meet the application's requirements. The current is drawn off by connection points, which typically are at the extreme ends of the fuel cell stack. DC power converters reduce or boost the voltage produced at the ends of the stack into a voltage that can be used by an attached device. However, these converters add cost, mass, volume, and potential failure points into the fuel cell system. With NASA Glenn's groundbreaking technique, the fuel cell stack includes a plurality of connection points to the device instead of having a fixed number of individual fuel cells. By connecting additional cells in the same stack to the device, the system power can be to be tailored to produce the required voltage for the connected device. Initially, this plurality includes a ground, a first connection point, and a second connection point. Additional connection points to the device can be added as needed, resulting in various powers that are available for use. Each connection point allows power to be drawn from the combined voltages of the fuel cells located between the connection point and the ground. This configuration permits the voltage to be adjusted to the system power requirements of the device without the need to add DC power converters to the fuel cell system to add additional fuel cell systems to meet the power demand of the device. For larger fuel cell configurations in particular, NASA's innovative technique results in a far less costly, more efficient means of power generation.

Aimed at structural applications up to 2700°F, NASA's patented technologies start with two types of high-strength SiC fibers that significantly enhance the thermo-structural performance of the commercially available boron-doped and sintered small-diameter “Sylramic” SiC fiber. These enhancement processes can be done on single fibers, multi-fiber tows, or component-shaped architectural preforms without any loss in fiber strength. The processes not only enhance every fiber in the preforms and relieve their weaving stresses, but also allow the preforms to be made into more shapes. Environmental resistance is also enhanced during processing by the production of a protective in-situ grown boron-nitride (iBN) coating on the fibers. Thus the two types of converted fibers are called “Sylramic-iBN” and “Super Sylramic-iBN”. For high CMC toughness, two separate chemical vapor infiltration (CVI) steps are used, one to apply a boron nitride coating on the fibers of the preform and the other to form the SiC-based matrix. The preforms are then heat treated not only to densify and shrink the CVI BN coating away from the SiC matrix (outside debonding), but also to increase its creep resistance, temperature capability, and thermal conductivity. One crucial advantage in this suite of technologies lies in its unprecedented customizability. The SiC/SiC CMC can be tailored to specific conditions by down-selecting the optimum fiber, fiber coating, fiber architecture, and matrix materials and processes. In any formulation, though, the NASA-processed SiC fibers display high tensile strength and the best creep-rupture resistance of any commercial SiC fiber, with strength retention to over 2700°F.

Glenn's approach utilizes a combination of alumina (Al2O3) and specially defined ratios of rare earth oxides. These rare earth elements are typically either yttrium or gadolinium, although other rare earths may be substituted to produce different targeted effects, including generating a multi-phase composition instead of a dual-phase one. Glenn's method of adding rare earths to the alumina material produces a two-phase composite system that is optimized for the targeted mechanical properties of wear resistance and coefficient of friction. These composites can be formed by either casting from a melt with directional solidification or solid-state sintering of isostatically pressed powder preforms. In the latter process, the hot isostatic pressing both reduces the porosity of the ceramic material and increases its density prior to the sintering process. Glenn's revolutionary technique yields a composite with significant advantages over single phase ceramics. Single phase ceramics, although they display high strength and wear resistance compared to other materials and high performance alloys like CoCr, also have a relatively high friction coefficient. The incorporation of rare earths allows the fabrication process to introduce a continuous second ceramic phase and create tertiary phases at the interfaces, which greatly improves the material's friction properties without sacrificing the wear characteristics. This combination of sturdiness and reduced friction gives these materials great potential for use in a wide range of applications.