Sublimable Propellant Source for Iodine-fed Ion Propulsion System

The advantages displayed by Glenn's AIE stem from a number of novel design concepts, centered on an annular discharge chamber with a set of annular ion optics. The annular discharge chamber increases the effective anode surface area for electron collection as compared to a conventional cylindrically shaped ion thruster of equivalent beam area. With this increased surface area, the AIE can operate at higher discharge currents and therefore high beam currents, thereby yielding a significantly increased (3x) thrust density. An annular-geometry flat electrode can be added to enable higher-perveance designs with even higher thrust densities, with improved F/P and efficiencies compared to more conventional, spherically domed electrodes. In addition, Glenn's design allows the neutralizer cathode assembly (NCA) to be placed in a central position within the annulus, which not only eliminates the cantilevered-outboard NCA used in most conventional ion thrusters but also enables a shared gimbal platform. These benefits make manufacturing the AIE simpler as well as allowing more compact engine designs. All of these advantages add up to an electric propulsion machine that yields superior performance over the entire Isp range, making the AIE attractive for next-generation SEP vehicles. Glenn's technological advance enables spacecraft to travel farther, faster, and more cheaply than with any other propulsion technology - with clear benefits for NASA and commercial space applications.

Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry on Earth. These fluids are typically contained in one of two ways; as low pressure, cryogenic liquids, or as a high pressure gases. Energy storage is not useful unless the energy can be practically obtained ("un-stored") as needed. Here the goal is to store as many fluid molecules as possible in the smallest, lightest weight volume possible; and to supply ("un-store") those molecules on demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach. The CFC's packaging is ingeniously designed, tightly packing aerogel composite materials within a container allows for a greater amount of storage media to be packed densely and strategically. An integrated conductive membrane also acts as a highly effective heat exchanger that easily distributes heat through the entire container to discharge the CFC quickly, it can also be interfaced to a cooling source for convenient system charging; this feature also allows the fluid to easily saturate the container for fast charging. Additionally, the unit can be charged either with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Finally, the heater integration system offers two promising methods, both of which have been fabricated and tested, to evenly distribute heat throughout the entire core, both axially and radially.

NASAs High Propellant Throughput Small Spacecraft Electric Propulsion thruster offers a propellant throughput capability of greater than 120 kg with a nominal thruster efficiency greater than 50%. The new thruster design combines heritage Hall thruster component design approaches with recent NASA GRC advancements in the areas of advanced magnetic circuit design, robust propellant manifolds, and center mounted cathodes. Prototypes of the High Propellant Throughput Small Spacecraft Electric Propulsion thruster have been fabricated and proof-of-concept has been demonstrated. A significant advancement in the High Propellant Throughput Small Spacecraft Electric Propulsion thruster is NASA's optimized magnetically shielded (OMS) field topology. The new OMS configuration reduces discharge channel erosion rates compared to conventional Hall thrusters, while reducing front pole cover erosion rates compared to traditional magnetically shielded Hall thrusters. This system also includes a largely unibody structure to reduce fabrication cost, increase strength, and optimize thermal management. A coupling plate between the high voltage discharge channel and low voltage thruster body allows more efficient thruster assembly and verification processes. Other design advancements further simplify assembly, improve robustness, and optimize performance.

The MXS produces electrons by shining UV light from an LED onto a photocathode material such as magnesium. The electrons are then accelerated across several kV and into a chosen target material; deceleration produces X-rays characteristic of the target. The MXS uses an electron multiplier for high X-ray production efficiency. The MXS is more compact, rugged, and power-efficient than standard X-ray sources. It can be manufactured using commercially available components and 3D printed housing, resulting in a low cost to manufacture. Unlike traditional X-ray sources, the MXS does not require a filament or vacuum and cooling systems. Most importantly, enabling rapid and arbitrary modulation allows using X-rays in the time domain, a new dimension to X-ray applications.

NASA's TVS Augmented Injector includes an internal heat exchanger, a fluid injector spray head, and an external surface condensation heat exchanger - all combined with multiple intertwined flow paths containing liquid, two-phase, and gaseous working fluid. The TVS provides a source of coolant to the injector, which chills the incoming fluid flow. This cooled flow promotes condensation of the tank ullage dropping pressure and maintains incoming fluid flow. The system eliminates the potential for a stalled fill condition and reduces tank pressure during cryogenic fluid transfer. During fill operations, the tank vent can be closed early in the process before fluid is introduced, and, in some cases, the tank vent may not even need to be opened. Furthermore, the TVS Augmented Injector can remove sufficient thermal energy to reach a 100% liquid level in the receiver tank. A cryo-cooler can be used in place the TVS flow circuit for a zero-loss system. The TVS Augmented Injector couples internal fluid flow cooling and external surface ullage gas condensation into a single, compact package that can be mounted to small tank flanges for minimal impact insertion into any vessel. The injector is printed as one part using additive manufacturing, resulting in part count reduction, improved reproducibility, shorter lead times, and reduced cost compared to conventional approaches. The injector may be of particular interest in applications where cryogenic fluid is expensive, fluid loss through vents is problematic, and/or achieving high filling levels would be helpful. The injector can benefit typical cryogenic fluid transfer between containers or, alternatively, can serve as a tank pressure control device for long-term storage using a fluid recirculation system that pumps fluid through the injector and sprays cooled liquid back into the tank. Additionally, where ISRU processes are employed, the injector can be used to liquefy incoming propellant streams.