Senior Flight Software Engineer

Vast is seeking a Senior Flight Software Engineer to own flight software development and verification for a new constellation-ready spacecraft bus — a product line designed to scale to hundreds of spacecraft per year.

This will be a full-time, exempt position located in our Long Beach location. 

About the role:

You'll start with a proven heritage FSW baseline from prior Vast missions and a reusable ground segment — that's your foundation, not your ceiling. The heritage system was built for single-satellite missions. The real work is scaling it for a constellation product line: new GNC algorithms, updated C&DH, payload interfaces for multiple customer types, fault protection, and autonomy — all architected to work across a fleet, not just one spacecraft. As the product line scales to hundreds of spacecraft per year, you'll solve the constellation-specific FSW challenges — configuration management across payload variants, fleet software updates, and multi-satellite operations support. You're the primary stakeholder and customer of the HITL lab, driving its requirements and using it as your verification environment. You'll build and lead a small FSW team to execute all of this.

Responsibilities: 

• Assess the heritage FSW baseline — catalog what's reusable, what needs modification, what's new for this mission
• Implement GNC software — attitude determination, CMG steering law, mode management, momentum management (the GNC lead defines the algorithms, you implement and verify them in flight code)
• Modify C&DH software — command and data handling, telemetry definitions, fault management updates for new bus architecture
• Develop payload interface software for multiple payload types across the manifest
• Build test and simulation infrastructure — unit test framework, software-in-the-loop (SIL) environment
• Drive HITL lab requirements — define what the lab needs to verify, serve as its primary stakeholder and customer
• Own flight software build, release, and configuration management processes
• Develop on-board fault protection and autonomy for the satellite bus
• Verify ground segment software interface compatibility (heritage ground segment, new bus)
• Solve constellation-scale FSW challenges — configuration management across payload variants, fleet software updates, and multi-satellite operations support
• Support on-orbit commissioning planning for FSW
• Build and grow an FSW team as the program scales — define roles and hire as complexity demands

Minimum Qualifications:

• Bachelor's degree in Computer Science, Electrical Engineering, Aerospace Engineering, or a related technical discipline
• 6+ years of embedded flight software development experience
• Spacecraft flight software development experience — C/C++ on Linux-based or embedded real-time systems
• Experience modifying and extending heritage flight software baselines (not just building from scratch)
• GNC software implementation — translating control algorithms into flight code with real-time constraints
• Experience defining HITL lab requirements and using HITL environments for FSW verification
• C&DH subsystem experience — command processing, telemetry, data storage, fault management
• Familiar with flight software V&V processes — unit test, SIL, HITL, integration test
• Comfortable owning an entire FSW subsystem on a fast timeline with a small team

Preferred Skills & Experience:

• Able to obtain a security clearance
• ADCS flight software experience on spacecraft or real-time robotics systems
• Multi-satellite FSW configuration management — handling payload variants across a constellation
• Experience with Linux-based flight software architectures
• RTOS experience (RTEMS, FreeRTOS, Zephyr, or similar) for microcontroller nodes
• Ground segment integration and compatibility testing