Embedded Software Engineer Intern - Spring 2027

Castelion Corporation•Torrance, CA

About The Position

Castelion is seeking motivated and talented Embedded Software Engineering interns for Spring 2027. The intern will help create software that drives and simulates missile systems, from low-level firmware on microcontrollers to high-level integration and testing tools. Working alongside embedded, hardware, and flight systems engineers, the intern will design, implement, test, and debug real systems in the loop. Contributions will support rapid prototyping and real-world tests. The role may require access to classified information or restricted U.S. Government sites, systems, or information. If designated, employment may be contingent on obtaining and maintaining a required U.S. Government security clearance or other authorization and meeting applicable eligibility requirements. The position requires access to export-controlled information, and hiring is contingent on the candidate being able to access applicable information without additional export licensing.

Requirements

Currently pursuing a BS or MS in Computer Engineering, Electrical Engineering, Computer Science, or a related technical field.
Rising junior, senior, or graduate student at the time of the internship.
Strong C/C++ programming skills for embedded systems.
Experience with microcontrollers or SoCs such as ARM, AVR, MSP430, or PIC.
Familiarity with developing in bare-metal or RTOS environments.
Understanding of board bring-up and debugging fundamentals.
Some familiarity with common protocols such as SPI, I2C, CAN, UART, or Ethernet.
U.S. Person status is required due to ITAR regulations.
Ability to access applicable export-controlled information without requiring additional export licensing.

Nice To Haves

Experience integrating analog/digital hardware with firmware.
Familiarity with missile systems, defense technology, or aerospace components.
Strong interest in working in a startup environment with high-impact projects.

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 and test boards, and debug at the intersection of electrical and software layers.
Collaborate 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 work clearly and share learnings to improve team knowledge and future designs.