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Ground Software Engineer

Torrance, California, United States
Full Time On-site

Summary

Job Description

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
  • 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

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

About Castelion

Castelion

Castelion is one of the fastest-rising defense technology companies focused on building affordable, rapidly deployable hypersonic strike systems for the U.S. military. Founded by former SpaceX leaders, the company is working to modernize how advanced weapons are developed and manufactured—using rapid iteration, vertical integration, and scalable production to deliver next-generation deterrence capabilities faster than traditional defense programs. Castelion’s mission centers on restoring America’s ability to field advanced military technology at speed and scale.

For job seekers, Castelion offers the opportunity to work directly on some of the most advanced technologies in national defense, including propulsion systems, avionics, flight software, guidance and navigation, missile systems, and advanced manufacturing. The company hires across aerospace engineering, embedded software, manufacturing, test engineering, avionics, cybersecurity, and operations—making it especially attractive to engineers, builders, veterans, and mission-driven professionals who want hands-on ownership of real hardware.

Unlike traditional defense contractors, Castelion operates with a startup-style engineering culture modeled after rapid aerospace development environments. Employees work closely with flight hardware, testing, and production systems in a fast-paced setting where speed, accountability, and execution are prioritized. The company openly emphasizes a builder mentality—giving team members the chance to own major projects and contribute directly to systems with national security impact.

As the U.S. military increases investment in hypersonic weapons, missile modernization, and scalable deterrence capabilities, Castelion continues to grow rapidly through major government contracts and manufacturing expansion. For professionals seeking a high-growth aerospace and defense company where they can help shape the future of national security technology, Castelion is quickly becoming one of the most exciting employers in the defense innovation ecosystem.

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