Developing PALOMINO, a new satellite propulsion system with modular TILE components.- TILE lead: program manager for TILE, the primary component of the PALOMINO product.- Materials lead: provided leadership in materials research, materials selection and testing for the PALOMINO product.- Test engineering: overseeing several testing campaigns for TILE performance and environments testing including vacuum, thermal (hot and cryo), and vibration.Other projects have included:- electrochemical evaluation of supercapacitive PALOMINO component- product development of a custom aerogel component- testing and electrochemical evaluation of several ionic liquid propellants- evaluation of structural metals and polymers for PALOMINO- development of database system for manufacturing and test data- script development for data processing using python, especially pandas- data visualization using python matplotlib and seabornManager's recommendation:"Stephen has become the person who takes on problems others dismiss as 'too complicated,' and his findings in multiple areas have already had significant performance implications on Accion's thrusters. He owns and runs the projects he has, including team meetings and supplier management, and has done it with grace and attention to detail. He thinks not only about his own technical goals, but the impacts of his work on other parts of the system: manufacturability, scale, throughput, and ease of integration He makes the most of technical meetings and comes to them organized and prepared with data and new ideas. He sees opportunities for improved performance on most projects he touches.

Responsibilities and topics:• Mechanical testing: compression, tension, 3 & 4 point bend, microhardness (ownership at company)• Fractography (ownership)• Particle metrology: particle size and elemental analysis (ownership)• Powder product quality control (ownership)• Hazmat shipping (ownership)• Powder metallurgy research• High energy ball milling• Sintering• SEM, EDS, TGA, XRD• Solidworks

Responsibilities and topics:• Solid mechanics modelling with Abaqus/CAE• Experimental validation of material analytical subroutine• Project was related to the NASA Digital Twin concept• Mechanical testing• Non-destructive evaluation• Fracture detection• Digital image correlation (DIC)• Shape memory alloysProject Title: Non-Destructive Evaluation of Aircraft Structures using Shape Memory AlloysOccurrence of stress-induced phase transformation in shape memory alloys (SMAs) emits a measurable acoustic signal. This phenomenon could be utilized by embedding microscopic SMA particles in aircraft structural members to detect the growth of fatigue cracks, thus reducing periodic destructive structural evaluations. A method for characterizing the embedded microscopic shape memory alloy particles was developed. Experiments were designed to capture micro-SMA-particle and macro-aluminum-matrix mechanical behavior simultaneously on fatigue crack growth specimens. A concurrently micro- and macro- 3D digital image correlation setup was developed together with Correlated Solutions. Responsibilities included micro- and macro- DIC setup, servo-hydraulic test frame setup, specimen preparation, basic DOE, mechanical testing execution, and results presentation, as well as coordinating with the team on basic fracture surface analysis in SEM and experiment-to-FEA model comparison and calibration.

Responsibilities and topics:• Solid mechanics modelling with Abaqus/CAE• Experimental validation of material analytical subroutine• Mechanical testing• Digital image correlation (DIC)• Infrared thermography• Shape memory alloys• Data manipulation and visualization with Python• Constitutive model manipulationProject title: Advanced Methods for Characterization of Shape Memory AlloysA method was desired to fully capture the SMA constitutive model properties from a single experiment for thermally induced SMA phase-transformation. Digital image correlation was used together with IR thermography to measure full-field mechanical behavior and full-field temperature simultaneously on an irregularly heated specimen. Responsibilities included equipment evaluation and purchase (DIC, IR thermography), experiment planning, experiment setup and execution, data manipulation and visualization using the Python matplotlib library, and FEA modelling and constitutive model manipulation for comparison to the experimental results.

• Aerospace Structural Design• Aerospace Engineering Statics

Project title: Identification of Characteristic Parameters for the Phase Transformation of Shape Memory Alloys Using Full Field Measurements and Inverse MethodsThe project was designed to experimentally capture SMA mechanical behavior due to multi-modal loading during stress-induced phase transformation. The SMA constitutive model was updated based on the experimental results. Responsibilities included execution of the experiments and collecting data, making basic modifications to the constitutive model, and aligning the experimental full-field data to the model mesh for 1-to-1 comparison.