Capacitive Impedance Water Ice Sensor (CIWIS)

When a lightning leader propagates through the atmosphere in the vicinity of an aircraft, the lightning electromagnetic emissions generated from the moving electrical charge will radiate the aircraft surface before the actual strike to the aircraft can occur. As the lightning leader propagates closer to the aircraft, the radiated emissions at the aircraft will grow stronger. By design, the frequency bandwidth of the lightning radiated is in the range for SansEC resonance. Hence the SansEC coil will be passively powered by the external oscillating magnetic field of the lightning radiated emission. The coil will resonate and generate its own oscillating magnetic and electric fields. These fields generate so-called Lorentz forces that influence the direction and momentum of the lightning attachment and thereby deflect/spread where the strike entry and exit points/damage occurs on the aircraft.

This technology was developed to improve Armstrong's multi-patented FOSS system, which has long been used to measure temperature and liquid levels in cryogenic environments. When the sensing system's fibers trapped humidity from the surrounding environment before their submersion into cryogenic liquids, the moisture adversely affected outputs. A new manufacturing process solves this problem, increasing reliability and accuracy not only of NASA's FOSS but also any fiber optic sensing system. How It Works Armstrong has developed a two-step process to assemble the sensors. First, the bare sensor fiber is inserted into an oven to expel all moisture from the fiber coating. Then, the moisture-free fiber is placed inside a humidity-controlled glove box to prevent it from absorbing any new moisture. While inside the glove box, the fiber is inserted into a loose barrier tubing that isolates the fiber yet is still thin enough to provide adequate thermal transfer. The tubing can be further purged with various gases while it is inside the glove box to provide additional moisture isolation. This innovation is particularly useful for fiber optic systems that measure temperature and that identify any temperature stratifications within cryogenic liquids. Why It Is Better This process seals sensor fibers from environmental moisture, enabling fiber optic sensing systems to operate reliably in humid environments. The innovation eliminates erroneous readings that can occur due to moisture collection on the fiber sensors. For more information about the full portfolio of FOSS technologies, see DRC-TOPS-37 or visit https://technology-afrc.ndc.nasa.gov/featurestory/fiber-optic-sensing

This NASA invention utilizes a simple waveguide-based measurement system to determine the complex dielectric permittivity and magnetic permeability of arbitrary-shaped planetary rock samples. The system operates at L-band frequencies (~1 GHz) and can be extended to P- and S-bands for broader applications. The approach involves placing an arbitrarily-shaped sample inside an open-ended waveguide excited by a coaxial probe, measuring the scattering parameters, and extracting dielectric and magnetic properties through computational modeling and optimization techniques. A key aspect of this system is its ability to handle non-uniform and irregularly shaped rock samples, enabling the measurement of real-world planetary materials without requiring extensive sample preparation. The methodology includes calibration in an anechoic chamber, computational modeling, and iterative refinement of measured vs. simulated scattering parameters to extract the material properties. Future advancements will involve expanding measurements to different frequency bands, refining computational models using artificial intelligence, and automatically rotating samples within the waveguide to obtain multiple directional measurements (enhancing precision while reducing test time). This NASA innovation has been successfully applied to two Martian meteorite samples, yielding values of dielectric permittivity and permeability relevant for Mars radar applications. The system will further be leveraged to build an expansive database of the dielectric properties of planetary soils and rocks to improve radar-based mapping (e.g., subsurface mapping) missions. The invention could also be applied for the non-destructive screening of a variety of samples using radio waves, including biological samples for medical purposes, additive manufacturing feedstock or finished parts, and mining-related rock samples to test for impurities or resources of interest. This NASA invention is at technology readiness level (TRL) 5 (component and/or breadboard validation in relevant environment) and is available for patent licensing.

Previous techniques for measuring dust accumulation, mostly de-pendent on solar cell output, were limited by their inability to distin-guish dust effects from other factors like incident radiation and radiation damage. These techniques were less effective in environ-ments with inconsistent solar flux and future missions, such as the Lunar South Pole, and lacked versatility in adapting to diverse envi-ronmental conditions. The PADS device embraces success over these challenges, and reflects enhanced features over prior iterations to also allow for space environments. Key design features begin with the customizable mechanical design of the PADS device for use in space environments, heaters with imbedded precision temperature sensors, a selected optical coating for the device coupons that are calibrated on high-fidelity thermal modeling and validated with ground-based testing to simulate the space environment of interest (including dusting with simulants representative of the planetary-body soil/regolith), and a control circuit for precision control/matching of the thermal inputs to the sensor via the heaters. Retainers with mount isolators are implemented to ensure the stacked layers within the device do not dislodge during high vibration or gravitational loads during launch. For operation, the PADS device is installed at the point of interest (e.g., space vehicle surface, extraterrestrial equipment) to quantify dust accumulation. Power and data transfer are done through cabling to the space vehicle system or can be provided standalone. A control circuit/algorithm adjusts the power to the heaters to precisely match the temperature setpoints. Ground testing in the simulated space environment conditions of interest creates a calibration plot of effec-tive emittance versus dust density, and allows determination of the degradation in emittance as the dust increases on the surface. Testing on the PADS device has been completed in a simulated lunar environment and data has been collected to enable sensor calibration for its use on the Moon. It is currently poised for integration into a lander for flight testing. Although the PADS device is intended for use in a burgeoning space industry and requisite environments – but given that the PADS device is partially comprised of programmable sensors in conjunction with optically coated coupons that can be tailored for custom use - it or its constituent components could be modified for terrestrial applications such as surface dust monitoring on photovoltaic panels or potentially combustible dust on various industrial surfaces.

In addition to previous LOTUS coating formulations, an additional optical formulation may be applied via vacuum deposition. This coating forms a top layer and may be applied in different thicknesses that serve to enhance its hydrophobic properties. The vacuum deposited material may comprise fluorinated ethylene propylene or a similar material. This coating is transparent and can be used on optical components or any other applications requiring a clear coating.