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.

Role Outcome

As a Lead Flight Software Engineer, you will serve as a key technical leader within Castelion's Flight Software organization. You will work closely with the Head of Flight Software to define architecture, guide engineering direction, and ensure reliable delivery of mission-critical embedded software across the vehicle stack. In addition to owning complex subsystems, you will mentor engineers, coordinate cross-functional efforts, and set the technical tempo for the team. This role is ideal for engineers who combine deep technical expertise with an ability to lead others, influence system-level decisions, and thrive in a fast-moving, highly integrated hardware - software environment.

Responsibilities

• Architecture & Technical Leadership: Partner with the Head of Flight Software to define system architecture, software design patterns, module interfaces, and long-term technical strategy. Provide technical leadership across embedded systems, autonomy, drivers, simulation, and application layers, and lead deep-dive investigations into software reliability, performance, and integration issues.
• Embedded Software Development: Design, implement, and integrate embedded software for Linux-based and real-time systems. Own high-impact subsystems from concept through flight testing. Perform hands-on debugging, hardware bring-up, and system validation across tightly coupled hardware–software interfaces.
• Team Leadership & Mentorship: Serve as day-to-day technical lead for the embedded software team by mentoring engineers, reviewing designs and code, and providing guidance on implementation approaches. Break down complex projects into clear milestones, track progress, and ensure high-quality execution across the team. Responsible for the career growth of other team members.
• Cross-Functional Collaboration: Work closely with avionics, guidance, hardware, simulation, and test teams to align software efforts with broader system requirements. Represent the embedded software team in program reviews, technical discussions, and mission-planning activities.
• System Integration & Testing: Lead software integration across virtualized environments, hardware-in-the-loop, and full vehicle setups. Develop or guide the development of testing tools, automation workflows, and simulation models. Drive root-cause analysis for complex failures and implement system-level corrective actions.
• Project Ownership & Delivery: Own major technical initiatives that impact vehicle capability, autonomy, performance, or reliability. Coordinate resources, manage risks, and ensure on-time delivery of mission-critical software. Support integration and launch activities at test sites when necessary.

• Quality, Standards & Continuous Improvement: Elevate engineering standards by driving improvements to code quality, design review processes, documentation expectations, and testing rigor. Foster a culture of high ownership, rapid iteration, and continuous improvement across the software organization.

Basic Qualifications

• Bachelor's degree in computer science, computer engineering, electrical engineering, math, or a related STEM field.
• 7+ years of professional experience in embedded software or real-time systems.
• Strong proficiency in C++, Rust, or similar systems programming languages.
• Experience developing software on Linux-based embedded platforms, including kernel-level work or custom driver development (UART, I2C, SPI, etc.).
• Experience leading technical projects, architecting complex systems, or serving as a team or technical lead.
• Strong debugging skills across hardware/software boundaries.

Preferred Skills and Experience

• Technical leadership experience at high-performance or mission-critical hardware–software organizations (defense, aerospace, robotics, automotive, etc.).
• Hands-on experience with real-time systems, microcontrollers (ARM, PowerPC, x86), and distributed embedded architectures.
• Strong Linux internals knowledge, including performance tuning, networking, and system-level diagnostics.
• Proven ability to mentor engineers and provide feedback, elevate engineering standards, and run design reviews.
• Experience aligning multidisciplinary teams and influencing system-wide decisions.
• Demonstrated ability to rapidly prototype, evaluate tradeoffs, and validate ideas using first-principles thinking.

Leadership Qualities

• Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.
• High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.
• Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.

ITAR Requirements

To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.

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.

All employees are granted long-term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.