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Senior Propulsion Engineer

Rio Rancho, New Mexico, United States
Full Time On-site

Summary

Job Description

The Senior Propulsion Engineer's primary responsibility is the design of solid rocket motor primary and secondary structures, along with propulsion components, with an emphasis on schedule, affordability and scale.

Responsibilities

  • Translate project objectives into cost-effective designs that can be produced at scale the Castelion way.
  • Spearhead the creation of innovative solid rocket motor designs, demonstrating autonomy even with limited expert guidance.
  • Actively engage in the assembly, testing, and troubleshooting of prototypes and production builds, providing expert guidance as necessary.
  • Use our rapid iteration cycles to validate product performance and facilitate necessary design adjustments.
  • Produce, evaluate, and authorize CAD models and drawings, adhering to internal standards and ASME Y14.5-2009 guidelines.
  • Provide thorough assessments and resolutions for any discrepancies in hardware, including supporting analyses when required.
  • Collaborate with supply chain to ensure seamless support and adapt designs to mitigate availability risks and time delays.

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

Leadership Qualities

Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.

High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.

Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

About Castelion

Castelion

Castelion is one of the fastest-rising defense technology companies focused on building affordable, rapidly deployable hypersonic strike systems for the U.S. military. Founded by former SpaceX leaders, the company is working to modernize how advanced weapons are developed and manufactured—using rapid iteration, vertical integration, and scalable production to deliver next-generation deterrence capabilities faster than traditional defense programs. Castelion’s mission centers on restoring America’s ability to field advanced military technology at speed and scale.

For job seekers, Castelion offers the opportunity to work directly on some of the most advanced technologies in national defense, including propulsion systems, avionics, flight software, guidance and navigation, missile systems, and advanced manufacturing. The company hires across aerospace engineering, embedded software, manufacturing, test engineering, avionics, cybersecurity, and operations—making it especially attractive to engineers, builders, veterans, and mission-driven professionals who want hands-on ownership of real hardware.

Unlike traditional defense contractors, Castelion operates with a startup-style engineering culture modeled after rapid aerospace development environments. Employees work closely with flight hardware, testing, and production systems in a fast-paced setting where speed, accountability, and execution are prioritized. The company openly emphasizes a builder mentality—giving team members the chance to own major projects and contribute directly to systems with national security impact.

As the U.S. military increases investment in hypersonic weapons, missile modernization, and scalable deterrence capabilities, Castelion continues to grow rapidly through major government contracts and manufacturing expansion. For professionals seeking a high-growth aerospace and defense company where they can help shape the future of national security technology, Castelion is quickly becoming one of the most exciting employers in the defense innovation ecosystem.

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