Propulsion Development Engineer

Hermeus is a venture-backed defense aviation company reclaiming the lost art of rapid iterative prototyping to build the fastest aircraft in the world today. By prioritizing relentless hardware iteration, we deliver high-speed systems at the pace of the modern battlefield. We work with the Department of War to provide the high-speed capabilities our nation and its allies need to maintain a durable, asymmetric advantage. About The Role:  As a Development Engineer on the Propulsion team, you will be responsible for advancing engine hardware through rapid, test-driven iteration. You will operate at the intersection of hardware execution and data analysis, owning engine test campaigns and translating results into actionable engineering improvements. This role requires strong hands-on capability, analytical rigor, and the ability to move quickly between test operations, data interpretation, and hardware problem-solving. You will play a critical role in increasing engine development velocity and reliability. Responsibilities • Own development engine test campaigns from planning through execution and post-test analysis • Define, author, and refine engine test plans, procedures, and setpoints aligned with program objectives • Support and make decisions during live test operations, including hot-fire and subsystem testing • Identify, diagnose, and resolve test-related engine issues across hardware, instrumentation, and procedures • Standardize and improve test data review, reduction, and reporting processes • Develop Python-based tools for data processing, visualization, and automated analysis • Translate test data into clear engineering insights, including performance characterization and root cause analysis • Drive post-test reviews and ensure actionable outcomes are captured and executed • Participate in hands-on engine build, integration, and test setup activities • Author and maintain development engine work instructions, test procedures, and technical documentation • Generate, track, and resolve engineering issues through ticketing systems • Collaborate cross-functionally with design, manufacturing, avionics, and test teams to resolve system-level challenges • Ensure proper sensor selection, instrumentation setup, and data integrity during test campaigns • Contribute to continuous improvement of test infrastructure, tooling, and development processes Requirements • Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, or a related discipline • Hands-on experience with hardware build, integration, or test operations • Experience developing or executing engineering test plans and procedures • Proficiency in Python for data analysis and automation • Strong understanding of sensors, instrumentation, and diagnostic techniques Preferred Skills and Qualifications • Experience with liquid rocket engines or air-breathing propulsion systems • Familiarity with high-speed data acquisition and telemetry systems • Background in thermofluids, combustion, or turbomachinery • Experience operating in fast-paced, iterative hardware development environments • Demonstrated ownership of hardware or test systems through multiple development cycles The salary range listed for this role is intended as a general guideline. Final compensation will be determined based on a variety of factors, including role scope and responsibilities, relevant experience, education and training, key skills, market data, and business needs. At Hermeus, compensation is only one part of our total rewards package. We offer competitive pay, equity, and a range of benefits designed to support our team. Benefits: Health & Wellness: 100% employer-paid healthcare and pet insurance Financial: Competitive pay, stock options, 401(k) retirement plan, and potential year-end bonuses Time Off: Paid parental leave, 12 federal holidays, unlimited PTO for exempt employees, and generous accrued PTO for non-exempt employees Office Perks: Weekly paid office lunches and fully stocked breakrooms   U.S. EXPORT CONTROL COMPLIANCE STATUS  The person hired will have access to information and items subject to U.S. export controls, and therefore, must either be a “U.S. person” as defined by 22 C.F.R. § 120.62 or otherwise eligible for deemed export licensing. US persons include U.S. citizens, U.S. nationals, lawful permanent residents (green card holders), and asylees and refugees with such status granted, not pending.    EQUAL OPPORTUNITY Hermeus is an Equal Opportunity Employer. Employment decisions at Hermeus are based solely on merit, competence, and qualifications, without regard to race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status.