About this opportunity
STEM Boomerang lists this Senior Mechanical Design Engineer (ACS Systems) opportunity in rio rancho, New Mexico. Review the employer’s description below for duties, qualifications and application requirements.
Job description
Senior Mechanical Design Engineer (ACS Systems)
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 Mechanical Design Engineer to design and deliver attitude control system (ACS) hardware for Castelion's long-range hypersonic strike vehicles. This role is critical to enabling reliable propellant storage, flow control, and thrust generation for precise vehicle control. You will work hands-on with multidisciplinary engineering teams to design, analyze, build, and validate ACS tanks, valves, thrusters, and integrated assemblies in a fast-paced, hardware-driven environment.
Requirements
Bachelor's, Master's, or PhD in Mechanical Engineering or related field
5+ years of experience in mechanical design for aerospace or high-performance fluid/propulsion systems
Strong background in pressure vessel design, fluid systems, and high-pressure component integration
Experience designing tanks, valves, thrusters, or similar propulsion or ACS hardware
Familiarity with sealing methods, leak detection, and cleanliness requirements for high-reliability fluid systems
Proficiency in CAD and analysis tools (e.g., NX, SolidWorks, ANSYS, or equivalent)
Experience with structural analysis, thermal analysis, and tolerance stack-up analysis
Familiarity with high-temperature materials and operation in extreme environments
Experience with hardware build, test, and troubleshooting in a lab or flight hardware environment
Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high flight 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
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Worksite address
rio rancho, NM, 87144, US
Who can apply
Review the original listing for work authorization, qualifications and employer requirements.