Embedded Software Engineer (All Levels)

Castelion; Torrance (CA); On-site; USD 110,000 - 150,000; Full time

Job summary

Castelion in Torrance, CA, is seeking an Embedded Software Engineer to create, develop, and test software that drives flight systems. You will collaborate with software and hardware teams to implement and debug across the stack—from applications and OS to firmware and simulation—and contribute to mission-critical capabilities.

We welcome engineers at all levels who are eager to solve problems in challenging environments and impact our defense mission.

Qualifications

• Educational background in a STEM field or equivalent practical experience.
• Experience with C++, Python, or Rust for systems programming.
• Familiarity with Linux-based development environments and low-level hardware interfaces.

Responsibilities

• Autonomous systems: design and implement reliable autonomous software systems and simulations.
• Comprehensive software development: manage the full lifecycle for mission-critical applications.
• System testing: debug hardware/software stacks, including hardware-in-the-loop and vehicle-in-the-loop testing.
• Collaboration: work with multidisciplinary teams on next-generation hypersonic missile capabilities.
• Project leadership: lead major projects and occasional travel to launch/customer sites.
• Improve standards: promote best practices within the software team.

Skills

C++

Rust

Python

Linux

Embedded systems

Systems programming

Education

Bachelor's degree in Computer Science, Computer Engineering, Electrical Engineering, Mathematics, or related STEM field

Tools

Linux kernel development

UART/I2C drivers

Hardware interfaces

Job description

Why Castelion, Why Now

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.

Why Castelion, Why Now

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we're building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage, where you'll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.

Embedded Software Engineer

As an Embedded Software Engineer you will be at the forefront of creating, developing, and testing the software that drives and simulates our flight systems. Your role involves close collaboration with fellow Castelion engineers across software and hardware domains to implement and debug software across the entire technology stack from applications and operating systems to networking, firmware, and simulation, ensuring complete mission success. We seek intelligent, collaborative, and driven engineers of all levels who are passionate about problem-solving and eager to contribute to an extraordinary mission. If you thrive in challenging environments and are excited by the prospect of making a tangible impact, we want to hear from you.

Responsibilities

• Autonomous Systems: Design and implement reliable autonomous software systems, along with the simulations required to validate their precision and dependability.
• Comprehensive Software Development: Manage the entire software development process, from initial design, prototyping, and testing, to final integration and deployment for mission-critical applications.
• System Testing: Evaluate test outcomes and troubleshoot issues necessitating detailed investigations, including hands-on integration and debugging of hardware/software systems. Develop tools to facilitate testing across various environments: virtualized hardware, real hardware-in-the-loop, and vehicle-in-the-loop testing.
• Collaboration: Partner with multidisciplinary engineering teams to brainstorm, design, and develop next-generation hypersonic missile capabilities, including advanced guidance algorithms and integrated seeker image processing.
• Project Leadership: Lead major projects that propel Castelion's mission forward, ensuring alignment with overall objectives and occasionally traveling to launch and customer sites for testing and operations.
• Enhance Standards and Practices: Continuously improve software standards and best practices within the software team, fostering an environment of ongoing improvement and innovation.

Basic Qualifications

• Educational Background: Bachelor's degree in Computer Science, Computer Engineering, Electrical Engineering, Mathematics, or a related STEM field, or equivalent practical experience.
• Experience: Open to candidates across all experience levels, from early-career engineers to senior technical contributors. Professional experience, internships, research, open-source contributions, or other hands-on technical work will be considered.
• Technical Proficiency: Experience with systems programming in languages such as C++, Python, or Rust, and familiarity with Linux-based development environments. Experience may include work with low-level systems such as Linux kernel development, hardware interfaces, or driver development (e.g., UART, I2C, or similar peripherals).

Preferred Skills And Experience

• Programming Expertise: Proven proficiency in C++, Rust, or similar systems programming languages.
• System Experience: Practical experience with real-time embedded systems or distributed computing environments in Linux-based systems, including developing high-quality Linux-based C++ software for common processors and microcontrollers (e.g., PowerPC, x86, ARM).
• Technical Skills: Proficiency in Linux, including Bash shell scripting, network troubleshooting, and performance analysis (strace, ftrace, etc.), with strong skills in debugging, performance optimization, and unit testing.
• System Knowledge: Comprehensive understanding of computer architecture and networking protocols (TCP, UDP, etc.).
• Problem-Solving: Innovative problem‑solving approach using first-principles thinking, including developing prototypes to validate key design concepts and quantify technical constraints.

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Additional Eligibility Requirements

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply.

Affirmative Action/EEO Statement

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law.

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact [e-mail]. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law.

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation.

EAR/ITAR Requirements

This position requires access to export-controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export-controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.