Senior Propulsion Engineer

Job Description
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:

The Senior Propulsion Engineer's primary responsibility is the design of solid rocket motor primary and secondary structures, along with propulsion components, with an emphasis on schedule, affordability and scale.

Requirements

Basic Qualifications

• Bachelor's or advanced degree in aerospace engineering, manufacturing engineering, materials engineering, mechanical engineering or physics.
• 5+ years of mechanical or fluids design, analysis, or build experience (student project team, university rocketry club and internship experience counts).
• Effective communication skills are crucial for collaborating with cross-functional teams, presenting design concepts, and documenting work.

Preferred Skills and Experience

• Proficient in test methods/setups, with the ability to conduct trade studies using engineering fundamentals to make informed recommendations, even with limited information.
• Extensive experience working with aerospace materials (including metals, plastics, and composites) and a solid understanding of spacecraft and/or launch vehicle propulsion systems and fluid components.
• Skilled in CAD software (NX 8.5 or similar packages like PTC Creo, CATIA) with expertise in geometric dimensioning and tolerancing (GD&T) per ASME Y14.5-1994.
• Relevant experience with rocket motors, solid propulsion elements, and structural interfaces, including knowledge of insensitive munitions protocols and practices.
• Hold a Masters degree or PhD in a technical discipline such as mechanical or aerospace engineering.
• Hands-on experience supporting rapid product development, including designing hardware for high-rate production in alternative non-aerospace domains.
• Currently hold an active DoD Secret Security Clearance or higher.

Additional Requirements

• Willing and able to work extended hours and/or weekends with minimal notification to meet critical deadlines leading up to major milestones.
• Able to travel up to 30% on an ongoing basis

Benefits

• Employee Equity: Meaningful equity forall full-time employees - share value has increased 150x in three years
• Personal Time Off: Four (4) weeks of paidtime off to unplug, reset, and come back sharp-velocity matters,burnout doesn't
• Company Paid Holidays: Ten (10) companypaid holidays
• Medical: We offer plans at 100% employeecovered and 80% of dependent coverage
• Dental & Vision: We cover 90%employees and 80% for dependents to ensure you and your family haveaccess to quality preventive and ongoing care
• FSA/HSA: To support long-term health andfinancial resilience, we offer FSA and HSA options that allowemployees to set aside pre-tax dollars for eligible medical anddependent care expenses
• Retirement: 401k plan offered to supportlong term financial growth along side high-impact, high-velocity work
• Paid Parental Leave: We support growingfamilies with meaningful time to bond and recover. Birthing parentsare eligible for up to 10 weeks of paid leave, while non-birthingparents may take up to 4 weeks of paid leave. This time can be usedfor pre-natal care, pregnancy, childbirth, and related medicalneeds-ensuring every parent has the support they need during thisimportant life moment.8-weeks of paid parental leave for allparents. Additional paid pregnancy leave for CA employees
• Meals & Catering: Frequently cateredlunches and team meals, plus company-covered meals when extra timeor effort is required
• Snacks & Beverages: Fully stockedkitchen with unlimited snacks and drinks to keep you fueledthroughout the day
• Performance & Fitness: $100 monthlyfitness stipend to support peak performance and health, both insideand outside of work
• EV Charging: Onsite electric vehiclecharging available for employees