Senior Flight Software Engineer

<div class="content-intro"><p>At Vast, our mission is to contribute to a future where billions of people are living and thriving in space. Vast is developing next-generation space stations to ensure a continuous human presence in space for America and its allies, enabling advanced microgravity research and manufacturing, and unlocking a new space economy for government, corporate, and private customers. Using an incremental, hardware-rich and low-cost approach, Vast is rapidly developing its multi-module Haven Station. Haven Demo’s 2025 success made Vast the only operational commercial space station company to fly and operate its own spacecraft. Next, Haven-1 is expected to become the world’s first commercial space station when it launches, followed by additional Haven modules to enable permanent human presence by 2030. Our team is all-in, committed to executing our mission safely and on time. If you want to work with the most talented people on Earth furthering space exploration for humanity, come join us.</p></div><p>Vast is seeking a <strong>Senior Flight Software Engineer </strong>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.</p> <p>This will be a <strong>full-time</strong>,&nbsp;<strong>exempt&nbsp;</strong>position located in our<strong>&nbsp;Long Beach&nbsp;</strong>location.&nbsp;</p> <p><strong>About the role:</strong></p> <p>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&amp;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.</p> <p><strong>Responsibilities:&nbsp;</strong></p> <ul> <li>Assess the heritage FSW baseline — catalog what's reusable, what needs modification, what's new for this mission</li> <li>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)</li> <li&g