Battery Test & Validation Engineer (High Voltage Packs & Modules)

At Heart Aerospace we develop the ES-30, a regional hybrid-electric airplane with a capacity of 30 passengers, an electric zero-emission range of 200 km and an extended hybrid range of 400 km. Heart is targeting type certification of the ES-30 by the end of the decade. Your Mission We are seeking a Propulsion Engineer to join our Dynamic Propulsion team in Torrance, CA. You will lead the testing, validation and certification of the aircraft’s hybrid-electric powertrain system. You will also interface across mechanical, thermal, propulsion, actuation, avionics, and battery teams to develop, execute, and analyze integrated system-level tests of the Electric Propulsion Unit (EPU) and its subsystems. Key responsibilities include but are not limited to: * Lead and execute system-level powertrain testing, including electric motor, inverter, gearbox, disconnect systems, and propeller subsystems. * Design and commission hybrid-electric propulsion test stands, HIL, and Digital Twin, including instrumentation, safety systems, control systems, and data acquisition. * Plan, execute, and document test campaigns to verify performance, safety, and certification compliance. * Collaborate with cross-functional teams to develop test procedures and test plans for integrated propulsion systems. * Coordinate with suppliers and external labs to support component and system-level testing. * Analyze test data, prepare reports, and provide feedback to design teams for iterative development. * Support environmental, endurance, fault-injection, and compliance testing for certification readiness. You'll Bring These Qualifications: * 2+ years of professional experience in powertrain, propulsion, or test engineering, with electric or ideally hybrid-electric systems. * Hands-on experience designing and operating powertrain or propulsion test stands with complex instrumentation and control. * Deep understanding of electric powertrains including motors, inverters, batteries, and thermal management systems. * Proficiency with data acquisition systems (e.g., dSPACE, NI, Dewesoft) and instrumentation (current/voltage sensors, thermocouples, strain gauges). * Experience developing automated test procedures and control scripts (e.g., Python, LabVIEW, or similar). * Strong analytical skills in interpreting test data and diagnosing system performance and failure modes. * Understanding of high voltage safety standards and procedures for testing environments. These Qualifications Would Be Nice to Have: * Familiarity with aerospace certification requirements (EASA CS-23/25 or FAA FAR Part 23/25). * Experience with DO-160 or MIL-STD environmental test standards. * Experience with root cause analysis and tools such as DFMEA and fault tree analysis. * Background in hybrid propulsion systems or aerospace propulsion integration. Education: * Bachelor’s or Master’s degree in Mechanical, Electrical, Aerospace Engineering, or related fields. Base Pay Range:  $124,000—$216,000 USD

YOUR MISSION As an Engineering Intern at Moonwatt, you will work at the intersection of embedded software, electronics design, and electrical engineering. Among others, you will work on the development, testing, and integration of our battery management system. This is a hands-on internship where you will be contributing directly alongside senior engineers, develop and test prototypes, and build our production firmware.  The internship is designed with a strong intention to convert to full-time for high performers. What You Will Work On Mechanical Design and Development * Actively contribute to the mechanical design of Moonwatt products using CAD tools (SolidWorks), from early concepts through detailed 3D models and technical drawings. * Perform Finite Element Analysis (FEA) to validate structural integrity, thermal behavior, and mechanical performance of components and assemblies. * Support the transition from design to physical prototype, working with manufacturing processes such as machining, sheet metal, and additive manufacturing. Participate in assembly, testing, and iteration cycles. * Work closely with internal teams (electronics, firmware, product) and external partners (suppliers, subcontractors, labs) to align mechanical designs with system-level requirements. * Produce and maintain engineering documentation including BOMs, assembly procedures, test reports, and design reviews. * Perform fail fast method to quickly deliver increments or prototypes that can be used to validate the feasibility or desirability of an idea or a project. * Perform mechanical assembly on sub or top assembly on product prototype. Electronics & Electrical Support * Assist electronics & electrical teams on the design of all electrical/electronic components with hardware design and assembly instructions.  * Support validation and testing of low-voltage and high-voltage electrical architectures within battery systems. Product development and organizational improvement * Setting up and managing custom property templates in SolidWorks (part number, material, revision, finish, etc.) to ensure consistent metadata across files. Designing and maintaining drawing templates * Contributing to the rollout of engineering best practices within the team (GD&T standards, model quality checklists, release workflows). YOUR PROFILE Must Have * Currently enrolled in a bachelor's or master's degree program in Mechanical Engineering.  * Solid foundation in mechanical design principles, materials, and manufacturing processes. * Proficiency in SolidWorks CAD tool. * Theoretical or practical knowledge of FEA simulation. * Knowledge of electricity fundamentals and battery systems. * Have an affinity for hands-on mechanical work. Thrive in a high-autonomy role and in fast-paced environments.  * Curious, precise, and eager to learn within a highly collaborative, multidisciplinary engineering environment. * Minimum internship duration of 6 months (end-of-study internship preferably). Nice to Have * Previous experience in students' organizations like Formula Student, Eco-Marathon teams or Fablab / Makerspace clubs will be highly valued. * Electrical and/or electronics knowledge or prior experience is a plus.  * Knowledge of DFM/DFA and tolerance analysis (GD&T). * Hands-on experience with prototyping (3D printing, machining, lab work). * Previous hardware bring-up experience including component-level testing and validation. * Interest or background in renewable energy, energy storage, or electric vehicles (EV) domains. * Awareness of hydraulics system challenges. WHY US? * An engineering internship with real responsibilities, not administrative tasks * Exposure to multiple disciplines beyond your core skillset * Direct mentorship from senior engineers and who built large-scale energy systems before * A learning environment where you will participate in decisions, not just observe * A path to full-time conversion for high-performing interns * A fast, mission-driven environment where engineering decisions matter