Mechanical Engineer Fall Co-Op

Position: Mechanical Engineer Fall 2026 Co-Op
About the job Mechanical Engineer Fall 2026 Co-Op

About Castelion

Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production 're designing, building, and testing next-generation long-range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Fall 2026 Mechanical Engineering Co-Op

Join us for a dynamic, hands-on experience developing next-generation missile systems. As an intern, you'll contribute directly to the design, testing, and integration of advanced defense technologies all within a fast-paced, collaborative startup environment where your work has immediate impact.

Key Responsibilities:

• Assist in the design, analysis, and testing of components for missile subsystems, including propulsion, guidance systems, power electronics, and more.
• Support engineering teams with simulations, modeling, and prototyping of critical hardware components.
• Conduct research and development tasks, gathering and analyzing data to inform design decisions.
• Participate in system integration efforts, helping to assemble and test subsystems in real-world test environments.
• Collaborate cross-functionally with engineering, manufacturing, and test teams to ensure project success.
• Document design processes, test results, and project progress, contributing to the continuous improvement of our systems.
• Attend technical reviews, design meetings, and team briefings to stay engaged with project developments and learn from industry experts.

Learning Opportunities:

• Gain hands-on experience in aerospace engineering, working on cutting-edge hypersonic missile systems.
• Develop your technical skills by working with high-performance teams and state-of-the-art tools.
• Learn about the full lifecycle of missile development, from design and prototyping to testing and final integration.
• Receive mentorship from experienced engineers and leaders in the aerospace and defense industry.
• Be a part of a fast-paced startup culture where innovation, teamwork, and rapid development are at the forefront.

Qualifications:

• Currently pursuing a Bachelor's or Master's degree in Mechanical Engineering, Aerospace Engineering, or a related field.
• Rising junior, senior, or graduate-level student preferred.
• Strong academic record with relevant coursework in areas such as mechanical design, propulsion, power systems, or related fields
• Hands-on experience through lab work, projects, or internships is a plus.
• Passion for aerospace, defense technology, and innovative engineering solutions.
• Excellent problem-solving, analytical, and communication skills.
• Ability to work collaboratively in a fast-paced, team-oriented environment.

Preferred Qualifications:

• Experience with hardware design, testing, data acquisition, and analysis.
• Familiarity with missile systems, defense technology, or aerospace components.
• Strong interest in working in a startup environment with high-impact projects.

Why Castelion?

At Castelion, you'll be part of a mission-driven company where every project matters. Our interns don't just observe - they contribute meaningfully to the success of our programs. This is a unique opportunity to work at the cutting edge of aerospace engineering while developing the skills and experience that will help you grow into a future leader in the field.

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…