Spring 2026 Engineering Internship

About the job Spring 2026 Engineering Internship

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 at scale. Were designing, building, and testing next-generation long-range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.

Spring 2026 Engineering Internship

Castelion is seeking motivated and talented engineering interns for Spring 2026. This internship offers a dynamic, hands-on experience working on cutting-edge missile systems, including SW, guidance, navigation and control (GNC), propulsion, power electronics, manufacturing, mechanical / structures, avionics, system integration, etc. You will contribute directly to the development, testing, and integration of advanced defense systems, while working in a highly collaborative startup environment.

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 :

Qualifications :

Preferred Qualifications :

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 :

ITAR Requirements :

Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin / ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.

This internship is paid at an hourly rate of $30 per hour. Compensation may vary based on experience and education level. For non-local interns, housing or relocation stipends may be available to help offset temporary living expenses.