Senior Propulsion Engineer (Rocket Motors)

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

Benefits offered by this job

Employee equity for full-time staff

Paid time off - 4 weeks

Medical coverage 100% for employees

Dental & Vision coverage 90% employees

FSA/HSA options

Retirement plan - 401k

Paid parental leave

Meals & catering

Snacks & beverages

Fitness stipend $100/month

Onsite EV charging

Job summary

Castelion in Rio Rancho, NM, seeks a Senior Propulsion Engineer to design, build, and test solid rocket motors for long-range hypersonic strike vehicles. You will work with multidisciplinary teams from concept through flight test in a fast-paced hardware-heavy environment.

The role emphasizes internal ballistics, grain design, nozzle performance, and solid motor testing with instrumentation and data analysis using MATLAB/ANSYS.

Qualifications

• Bachelor's, Master's, or PhD in Aerospace/Mechanical Engineering or related field.
• 5+ years in rocket propulsion design, analysis, and testing for aerospace/defense.
• Experience with solid rocket motor design, grain, nozzle, and internal ballistics.
• Proficient in MATLAB/ANSYS for analysis and modeling.
• Hands-on propulsion testing, static fire setup, and data interpretation.

Responsibilities

• Design, build, and test solid rocket motor systems for hypersonic vehicles.
• Lead integration and troubleshooting in lab/test environments.
• Collaborate with multidisciplinary teams from concept to flight test.

Skills

Solid rocket motor design

Internal ballistics

Grain design

Nozzle performance

MATLAB

ANSYS

Laboratory testing

Data analysis

Education

Bachelor's in Aerospace/Mechanical Engineering or related field

Master's or PhD (preferred)

Tools

MATLAB

ANSYS

Instrumentation

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, build, and test rocket motor systems for Castelion's long-range hypersonic strike vehicles. This role is critical to delivering reliable, high-performance propulsion across all mission phases. You will work hands-on with multidisciplinary engineering teams to develop solid rocket motors and associated hardware from concept through flight test in a fast-paced, hardware-driven environment.

Requirements

• Bachelor's, Master's, or PhD in Aerospace Engineering, Mechanical Engineering, or related field
  
• 5+ years of experience in rocket propulsion design, analysis, and testing for aerospace or defense applications
  
• Strong background in solid rocket motor design, including internal ballistics, grain design, and nozzle performance
  
• Experience with propulsion testing, including static fire test setup, instrumentation, and data analysis
  
• Familiarity with structural and thermal design considerations for high-temperature, high-pressure systems
  
• Proficiency in analysis and modeling tools (e.g., MATLAB, ANSYS, or equivalent)
  
• Experience with hardware build, integration, and troubleshooting in a lab or test environment
  
• 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