Ground Software Engineer

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 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

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.

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

Basic Qualifications

• 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

Preferred Skills and Experience

• 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