Archives: Portfolios

This research project focuses on how the solar wind interacts with the Martian atmosphere. As solar wind protons propagate towards Mars, they can interact with Mars’s extensive hydrogen corona through a process of charge exchange. These solar wind protons can obtain an electron from neutral atomic hydrogen in the corona, becoming fast energetic neutral atoms (ENAs) that maintain upstream solar wind velocity. These ENAs can bypass electromagnetic boundaries around the planet and penetrate to altitudes of ~130 km in the Martian atmosphere. Along their path of propagation, ENAs can undergo multiple charge-changing collisions as they interact with atmospheric neutrals (primarily CO₂), resulting in observable beams of H⁺ and H^– in the collisional atmosphere of Mars.  The goal of this project is to characterize the properties of H^– and H⁺ energy spectra in order to better understand charge exchange processes in the Martian atmosphere.

Thus far, we have implemented electron and ion data collected over seven years by the Solar Wind Electron Analyzer (SWEA) and Solar Wind Ion Analyzer (SWIA) onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft and have found some interesting behaviors.  We have observed seasonal increases in the H⁺ and H^– fluxes congruent with perihelion and Mars’s dust season, in addition to a turnover in the ratio of the H⁺ and H^– fluxes at a particular point within Mars’s atmosphere.  We have also found that this seasonal enhancement is stronger for H⁺ and are seeking to better understand the underlying cause of this behavior by examining hydrogen column densities, solar radiation input, and bow shock position.

Fluxgate magnetometers are important tools for measuring space plasmas. However, fluxgate baseline measurements are known to drift over time. This instability can make it difficult to resolve magnetic features like planetary crustal fields which are important to understanding planetary geology. My research focuses on characterizing a new design for a fluxgate magnetometer called the Tesseract that looks promising for making stable, reliable magnetic field measurements in a space environment. Tesseract was flight demonstrated on the ACES-II sounding rockets. This project will focus on a detailed characterization of Tesseract’s performance, both in the laboratory using specialized testing equipment, and in space over the course of the rocket flight.

Solid-state magnetometers have recently stimulated interest due to their smaller size, weight, and power (SWaP) compared to existing magnetometers, and their potential to self-calibrate without expensive spacecraft maneuvers; two attractive features which help conserve spacecraft fuel. However, extensive research must be completed to optimize this new technology, and a detailed theory is the first step.

My research involves the investigation of the roles that microbial biofilms have in metal corrosion. Since the beginning of the Space Program in 1962, NASA has been combating corrosion. This is especially true for the launch equipment at the Kennedy Space Center that is subjected to exposure to salinity through ocean spray and fog. To combat this, current corrosion protection protocols employ the use of corrosion resistant materials, organic coatings, corrosion inhibitors, and electrochemical protection agents. These methods come at high monetary cost, and can lead to heavy environmental contamination. One alternative method that could be employed to combat this problem is the development of a microbiologically influenced corrosion inhibiting (MICI) biofilm that is applied directly onto metal surfaces as a protective layer.

Biofilms are biological systems that have the ability to accomplish multiple functions, and are both self-healing and adaptive especially when composed of complex microbial communities. Currently, I have am comparing the corrosion outcomes of steel and aluminum surfaces with environmental biofilms grown from various local soil/water sources and pure culture biofilms such as Bacillus cereus, Shewanella putrefaciens, and Pseudomonas fluorescens. Overall, our results will shed light on the complex interactions between naturally occurring microbial biofilms and metal surfaces with a focus on corrosion outcomes. By filling this critical knowledge gap, we will be able to develop a novel 3D printed self-healing biofilm made up of multiple species of MICI bacteria to help combat corrosion.

X-ray telescopes are critical for studying a myriad of high-energy sources: black holes, hot plasma surrounding galaxies, and the atmospheres of stars. Given this, the 2020 Decadal Survey on Astronomy and Astrophysics, which guides the science priorities of NASA’s Astrophysics Division, recommended an X-ray flagship mission for launch in the 2040’s. However, the Astrophysics Division’s Biennial Technology Report identified X-ray mirrors needed for such a mission as a Tier 1 (“highest priority”) technology gap.

Current methods of X-ray mirror fabrication create significant figure distortion and degrade mirror performance. My research project will contribute to the maturation of two adjustable X-ray optic technologies aimed at closing this technology gap. Both concepts will use thin-film piezoelectric actuators deposited on the back of a mirror. When supplied a voltage, these actuators bend the mirror’s shape locally. Utilizing an array of actuator cells across the mirror’s surface, we can induce more complex figure changes. With high precision optical metrology, we can measure and apply a deterministic figure correction to the mirror, increasing its angular resolution. The first technology uses lead zirconate titanate (PZT) for the piezoelectric material, while the second concept will use electroactive polymers. Electroactive polymers can be processed at lower temperatures than PZT, making X-ray mirrors less susceptible to deformation from thermal stress. However, electroactive polymer actuators are currently at a lower technology readiness level than PZT. High precision metrology will be used to characterize not only the dynamic range of these technologies, but ultimately their performance at figure correction.

My research project focuses on the synthesis, structural evaluation, and property optimization of glassy solid electrolytes for their use in all solid-state batteries (SSB). My objective is to create a SSB that is safer than their liquid electrolyte counterparts that can be used for space or vehicular technologies. More explicitly, my project explores the development of a new class of Glassy Solid Electrolytes (GSEs), a mixed oxy-sulfide-nitride (MOSN), which has the potential to overcome the conductivity, cost, and stability disadvantages of current solid electrolytes (SEs) needed for an all SSB. This unique class of materials exhibits high ionic conductivities of the sulfide glasses, improved chemical stability due to the inclusion of oxide glasses, and improved electrochemical stability when in contact with lithium metal because of the addition of oxy-nitride glasses. I hope to find an electrolyte that can be easily synthesized, optimized, and then placed into a SSB design to test the capabilities of these electrolytes.

This research aims to apply multiple turbulence generation methods to a plane within the computational domain, rather than at the inlet as is usual. The advantage of this is in its computational efficiency. The efficiency of Computational Fluid Dynamics (CFD) simulations is greatly affected by the mesh, or grid, on which they are solved. A finer mesh will yield more accurate results but take a significantly longer time to complete. By applying turbulence further in the domain than the inlet (i.e. closer to the airfoil or test body), the mesh can be coarser near the inlet and only be refined where the turbulence is applied. Otherwise, the fine mesh would have to cover the whole domain, as turbulence will quickly dissipate artificially without very small grid sizes. The other purpose of this research is to produce a turbulence generation method which combines existing methods in order to reduce the adaptation distance after the turbulence is injected. Turbulence generated in computational domains require some distance after their injection in order to stabilize and naturalize to the specific flow conditions. This can lengthen computational domains and further slow efficiency. Multiple methods have been shown to reduce this distance, and I plan to implement some of these in my work.

Characterizing plasma-wave interactions is critical to understanding particle energization mechanisms in space plasma environments and in applied technical fields. Currently, there is no conventional scattering theory for waves in plasma physics. Our research project is focused on the study of waves interacting with plasma ions trapped in a dipole magnetic field. Charged particles in a dipole field undergo a range of periodic and chaotic orbits, providing a general particle trajectory as a test bed for plasma wave scattering. Laser-induced fluorescence (LIF) techniques allow measurement of incident and reflected wave coefficients of ion acoustic waves launched toward the trapped plasma, allowing comparison to models being developed for describing the physics of these plasma wave interactions. Using LIF, we plan to describe approaching and trapped ion behavior as a function of velocity, as well as the incident and reflected wave interactions with the ions. Initial Langmuir Probe measurements have been made to describe the plasma conditions in and around the dipole magnet, and to measure the wave-induced variations in particle flux as a function of time and distance from the magnet.

Resupply missions for spacecraft suffer from limited cargo space, requiring prioritization of materials. Improvements to supply availability and variety could be made with the production of devices on demand where raw material is transported instead. This would allow for the freedom to produce a device independently, making the most out of limited cargo space. Electrohydrodynamic EHD inkjet printing is a printing technique that uses an electric field to jet the ink onto a substrate. The electric field has the effect of pulling the ink onto the working substrate, allowing the printer to function effectively in a low-gravity environment, as well as focusing the ink into a stream smaller than the printhead nozzle, allowing for micron-level resolution. This printing technique has different ink requirements than more traditional inkjet printing, and, being relatively new, there are no commercially available inks for use in EHD printing. Prior art examines conductive materials (silver, gold, copper, etc.) but not non-metallic materials, which provide broader functionality to electronics, giving the ability to produce dielectric and semiconductor devices. My current research involves the development of a reactive zinc oxide ink for the printing of transistors and memory devices. Motivation towards this approach, as opposed to a more conventional nanoparticle dispersion, was brought about by the potential of higher levels of printing resolution being unhampered by particle size and the ability to deposit ink within already fabricated nanoscale silicon substrates. Final device functionality is heavily dependent upon materials synthesis and processing. Electronic properties and device type, for example, may be selected through the level of crystallinity of the material or lack thereof (amorphous). The utilization of multiple materials to create a final device (a metallic ink to produce a conductive pattern and a ceramic ink to provide functionality) and long-term goals of utilization on the International Space Station necessitate the development of an ink to deposit a ceramic layer that can be processed at a low temperature.

My research project focuses on the integration of unmanned aerial vehicles (UAVs) into traditional air traffic systems operating in proximity to airports, which is a topic of ongoing investigation by various NASA research groups. This research falls within the broader domain known as Urban Air Mobility (UAM), which strives to create an efficient autonomous vehicle system for urban environments characterized by heavy air traffic. The primary goal of UAM is to ensure the safe and efficient operation of UAVs in complex urban airspace. Weare developing a cooperative planning and control framework that will enable the safe integration of UAVs into traditional air traffic systems. The bulk of this work lies in quantifying the rules of the road of aerial navigation and to then design an optimal control framework that provides the UAVs with optimal, efficient, and guaranteed-safe trajectories to allow the integration of UAVs into the complex, safety-critical environment that is the airspace. This cooperative planning and control framework will enable UAVs to navigate through the airspace, respond to dynamic changes in traffic patterns, and make autonomous decisions to avoid collisions with manned aircraft. This research has the potential to revolutionize the airspace, allowing UAVs to coexist seamlessly with conventional air traffic systems. With this work, we aim to enhance the safety and efficiency of urban airspace and contribute to the realization of Urban Air Mobility.