Senior Propulsion Engineer (Rocket Motor Soft Goods)

STEM Boomerang; Rio Rancho (NM); On-site; USD 140,000 - 210,000; Full time

Benefits offered by this job

Equity for employees

PTO 4 weeks

Medical insurance 100%

Dental & Vision coverage

401k retirement plan

Parental leave

Meals provided

Snacks & beverages

Fitness stipend

EV charging onsite

Job summary

Castelion in Rio Rancho, NM is seeking a Senior Propulsion Engineer to design and deliver rocket motor soft goods for long‑range hypersonic strike vehicles. You will work hands‑on with multidisciplinary teams to design, analyze, build, and validate soft goods systems in a fast‑paced, hardware‑driven environment.

Candidates should have 5+ years in rocket propulsion, a degree in aerospace/mechanical/materials, and strong experience with insulation, liners, bonding, and high‑temperature materials.

Qualifications

• 5+ years in rocket propulsion or high‑temperature material systems with focus on soft goods or internal motor components.
• Strong background in insulation materials, liners, and bonding systems in solid rocket motors.
• Experience with thermal protection materials under high heat flux and pressure.
• Familiarity with propellant compatibility and chemical interactions with soft goods materials.
• Material processing for elastomers, ablatives, or composite insulation systems.
• Proficiency in MATLAB, ANSYS, or equivalent.
• Experience with propulsion testing, data analysis, and failure investigation.
• Problem‑solving mindset in a fast‑paced hardware‑rich environment.

Skills

Aerospace Engineering

Propulsion

Thermal Protection

Materials Science

MATLAB

ANSYS

Data Analysis

Education

Bachelors/Masters/PhD in Aerospace/Mechanical/Materials

Tools

MATLAB

ANSYS

Job description

Rio Rancho, United States | Posted on 08/06/2026

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:

We are seeking a Senior Propulsion Engineer to design and deliver rocket motor soft goods for Castelion's long-range hypersonic strike vehicles. This role is critical to ensuring reliable motor performance, structural integrity, and thermal protection through the design of liners, insulators, inhibitors, and related internal components. You will work hands-on with multidisciplinary engineering teams to design, analyze, build, and validate soft goods systems in a fast-paced, hardware-driven environment.

Requirements

• Bachelor's, Master's, or PhD in Aerospace Engineering, Mechanical Engineering, Materials Science, or related field
  
• 5+ years of experience in rocket propulsion or high-temperature material systems, with focus on soft goods or internal motor components
  
• Strong background in insulation materials, liners, and bonding systems used in solid rocket motors
  
• Experience with thermal protection materials and behavior under high heat flux and pressure environments
  
• Familiarity with propellant compatibility, adhesion, and chemical interactions with soft goods materials
  
• Experience with material processing techniques for elastomers, ablatives, or composite insulation systems
  
• Proficiency in analysis and modeling tools (e.g., MATLAB, ANSYS, or equivalent)
  
• Experience with propulsion testing, data analysis, and failure investigation
  
• Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high test cadence environment
  
• 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
  
• 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