Senior Warhead Design Engineer

**Why Castelion, Why Now** Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts. This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact. **Senior Warhead Design Engineer** Castelion is designing and building next-generation hypersonic weapon systems that restore stability through credible deterrence. We are seeking a hands-on, mission-driven Senior Warhead Design Engineer to lead the design, development, and integration of advanced next-generation systems for our long-range hypersonic strike vehicles. This is a high-impact role for someone with deep expertise in energetic devices and safe & arm mechanisms, who thrives in a fast-paced, hardware-rich development environment. **Responsibilities** - Own the design, development, and qualification of ordnance systems, including: Initiators, detonators, transfer charges, explosive bolts, safe & arm devices. - Define requirements and interface specifications across mechanical, electrical, and software boundaries. - Lead supplier engagement, component selection, and build-to-print efforts with a focus on manufacturability, cost, and performance. - Drive development test planning, execution, and analysis for ordnance systems (including arena testing, function testing, and environmental qualification). - Work closely with systems, propulsion, avionics, and GNC teams to ensure ordnance components integrate safely and effectively into the full weapon system. - Support FMEA, fault-tree analysis, and safety case development. - Own documentation and compliance to MIL-STD-1316, MIL-STD-1910, AFSPCMAN 91-710, and other relevant standards. **Basic Qualifications** - B.S. or M.S. in Mechanical Engineering, Aerospace Engineering, or related field. - 5+ years of experience in ordnance or energetics design, analysis, and test - Familiarity with relevant DoD and NASA standards (e.g., MIL-STD-1316, MIL-STD-1901A, etc.). - Hands-on test experience in high-consequence environments. - Strong communication and documentation skills. - Active or eligible for a U.S. security clearance. **Preferred Skills and Experience** - Experience working with DoD customers and navigating military qualification processes. - Background in hypersonics, missile systems, or space launch vehicles. - CAD and mechanical analysis experience (e.g., SolidWorks, FEA tools). - Experience with additive manufacturing tools and capabilities. Prior experience working at a defense startup or fast-moving development organization. **Other Duties** Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice. **Benefits And Perks** All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day. *While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued securit…