Castelion was founded to restore America’s ability to field advanced weapons at speed and scale. Inspired by the engineering urgency of the WWII and Apollo eras, we combine rapid iteration, vertical integration, and scalable manufacturing to deliver affordable, high-performance strike systems. Our mission: rebuild industrial agility to strengthen national security and outpace evolving threats.

About the Role:

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.

Requirements

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.

Benefits

Employee Equity: Meaningful equity for all full-time employees - share value has increased 150x in three years
Personal Time Off: Four (4) weeks of paid time off to unplug, reset, and come back sharp—velocity matters, burnout doesn't
Company Paid Holidays: Ten (10) company paid holidays
Medical: We offer plans at 100% employee covered and 80% of dependent coverage
Dental & Vision: We cover 90% employees and 80% for dependents to ensure you and your family have access to quality preventive and ongoing care
FSA/HSA: To support long-term health and financial resilience, we offer FSA and HSA options that allow employees to set aside pre-tax dollars for eligible medical and dependent care expenses
Retirement: 401k plan offered to support long term financial growth along side high-impact, high-velocity work
Paid Parental Leave: We support growing families with meaningful time to bond and recover. Birthing parents are eligible for up to 10 weeks of paid leave, while non-birthing parents may take up to 4 weeks of paid leave. This time can be used for pre-natal care, pregnancy, childbirth, and related medical needs—ensuring every parent has the support they need during this important life moment.8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees
Meals & Catering: Frequently catered lunches and team meals, plus company-covered meals when extra time or effort is required
Snacks & Beverages: Fully stocked kitchen with unlimited snacks and drinks to keep you fueled throughout the day
Performance & Fitness: $100 monthly fitness stipend to support peak performance and health, both inside and outside of work
EV Charging: Onsite electric vehicle charging available for employees

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