Senior Mechanical Design Engineer (ACS Systems)

Castelion Corporation•Rio Rancho, NM

About The Position

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
U.S. citizenship is required

Nice To Haves

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required.

Responsibilities

Design and develop ACS hardware, including propellant tanks, valves, thrusters, and associated fluid system assemblies
Lead the architecture and detailed design of pressure vessels, fluid lines, mounts, and integrated ACS packaging within the vehicle
Perform structural, thermal, and fluid analyses to ensure performance and reliability under extreme pressure, temperature, and dynamic environments
Work closely with propulsion, GNC, avionics, and structures teams to ensure seamless integration of ACS systems with vehicle architecture
Conduct tolerance analysis, sealing strategy development, and leak-tightness assessments for high-pressure systems
Support prototyping, assembly, and hardware bring-up, including troubleshooting and root cause analysis of system performance issues
Define and execute qualification and environmental test plans, including pressure, vibration, thermal, and shock testing
Optimize designs for mass, reliability, manufacturability, and ease of integration
Mentor junior engineers and contribute to best practices in mechanical and fluid system design
Partner closely with program leadership to make technical trades aligned with mission success

Benefits

Meaningful long-term equity
Four (4) weeks of paid time off
Ten (10) company-paid holidays
Comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage
Dental and vision plans
Paid parental leave
$100 monthly fitness stipend
Onsite EV charging
Catered meals
Company-covered food during high-demand periods
Fully stocked kitchen