Ground Software Engineer
About The Position
Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus and technical excellence are decisive advantages - and we are building a team that can deliver real capability, not just concepts. This is a rare opportunity to join at an early stage, where your work will directly shape critical systems, influence major technical decisions, and have immediate, real-world impact. Ground Software Engineer on the Flight Software team is responsible for building the software systems that connect engineers to flight hardware throughout development, integration, testing, and flight operations. In this role, you will develop vehicle command and control systems, telemetry infrastructure, test automation tools, and mission-critical software that enables rapid iteration of Castelion's next-generation strike systems. This position offers the opportunity to work at the intersection of software, hardware, and flight testing, making a direct contribution to accelerating vehicle development and increasing flight-test velocity.
Requirements
- Bachelor's degree in Computer Science, Electrical Engineering, Aerospace Engineering, or a related technical field
- 1+ years of professional software engineering experience with strong proficiency in Python
- Experience developing software on Linux systems and working with networking protocols such as TCP/IP and UDP
- Experience building backend services, distributed systems, automation frameworks, or hardware-integrated software systems
- U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.
- The ability to obtain and maintain a U.S. government–issued security clearance is required.
Nice To Haves
- Experience supporting aerospace, defense, robotics, autonomous systems, or other mission-critical hardware programs
- Experience with telemetry systems, real-time data processing, time-series databases, or data visualization platforms
- Experience with Docker, Kubernetes, CI/CD pipelines, and modern software deployment practices
- Experience supporting hardware-in-the-loop (HIL) testing, system integration, or flight test operations
- Experience developing operator interfaces, mission control systems, or engineering tools using React, Vue, or similar frameworks
Responsibilities
- Design, develop, and maintain software systems for vehicle command, control, telemetry, and test operations
- Build and support ground software infrastructure used for hardware-in-the-loop (HIL), integration, and flight testing
- Develop backend services, automation tools, telemetry pipelines, and operator-facing applications using Python and modern software frameworks
- Integrate software with avionics, flight computers, test equipment, and communication systems to enable end-to-end vehicle testing
- Support flight campaigns, system debugging, and root-cause investigations across software and hardware interfaces
Benefits
- Meaningful long-term equity
- Four (4) weeks of paid time off
- Ten (10) company-paid holidays
- Comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans
- Paid parental leave
- $100 monthly fitness stipend
- Onsite EV charging
- Catered meals
- Company-covered food during high-demand periods
- Fully stocked kitchen
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What This Job Offers
Job Type
Full-time
Career Level
Entry Level
