Senior Propulsion Engineer

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.

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 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