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Mechanical Engineer

Torrance, California, United States
Full Time On-site

Summary

Job Description

Castelion is seeking a hands-on, high-agency Mechanical Engineer excited to take ownership of real flight hardware and grow alongside a fast-moving team. You will work on the design, fabrication, and integration of critical flight structures and mechanisms across Castelion's hypersonic vehicles. This role is ideal for someone who thrives in fast-paced environments, learns quickly, and wants to see their work go from concept to flight in weeks-not years. You'll be empowered to take on meaningful responsibilities immediately. This is a rare opportunity to grow as a full-stack engineer while working on hardware that matters.

Responsibilities

  • Design and Develop Flight Hardware: Support the design, analysis, and build of mission-critical systems including composite tanks, separation mechanisms, and actuators. You'll contribute to CAD models, run basic analysis, and work with technicians and leads to integrate and test hardware.
  • Rapid Iteration and Prototyping: Contribute to four-week subsystem prototype cycles. Participate in design reviews, integrate test feedback, and help drive continuous improvement based on real-world data.
  • Get Hands-On and Learn Fast: Work closely with leads and technicians during builds. Learn how to write travelers, build notes, and quality documentation. Gain exposure to the full product lifecycle in a highly accelerated environment.

Basic Qualifications

  • Educational Background: Bachelors degree in Mechanical Engineering with 2+ years of professional ME experience, preferably in aerospace, automotive, or hardware-focused industries.
  • Technical Skills: CAD design of mechanical components (e.g., SolidWorks, NX, or similar); understanding of statics, dynamics, and thermal principles
  • Ownership Mentality: Eager to take on responsibility, contribute in a hands-on environment, and learn from experience
  • Attention to Detail: Thoughtful about part numbers, materials, tolerances, and documentation-even when moving quickly

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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