Summer 2026 Mechanical Engineering Internship

Castelion Corporation • Torrance, CA

4h

About The Position

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. We'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.
Summer 2026 Mechanical Engineering Internships
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.

Requirements

• 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.

Nice To Haves

• 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.

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.

Benefits

• 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.

What This Job Offers

• Career Level: Intern