Embedded Software Engineer Intern - Summer 2026 (Avionics)

Job Description

Job Description

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. 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.

Embedded Software Engineer Intern - Summer 2026 (Avionics)

Castelion is seeking motivated and talented Embedded Software Engineering interns for Summer 2026. You'll help create the software that drives and simulates our missile systems, from low-level firmware on microcontrollers to high-level integration and testing tools. You'll work alongside experienced embedded, hardware, and flight systems engineers to design, implement, test, and debug real systems in the loop.

You wont be writing throwaway code; your contributions will directly support our rapid prototyping and real-world tests.

Responsibilities

• Develop, test, and debug low-level firmware for embedded systems and flight hardware
• Write and integrate device drivers for sensors, actuators, and missile subsystems
• Bring up new hardware, test boards, and debug at the intersection of electrical and software layers
• Collaborate cross-functionally with hardware, GNC, and flight test teams to ensure robust integration
• Participate in design reviews, hardware-in-the-loop tests, and on-the-bench bring-up and validation
• Document your work clearly and share learnings to improve team knowledge and future designs

Basic Qualifications

Preferred Skills and Experience

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.

You'll leave with

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.