Senior Guidance, Navigation, & Control (GNC) Engineer

K2 is building the largest and highest-power satellites ever flown, unlocking performance levels previously out of reach across every orbit. Backed by $450M from leading investors including Altimeter Capital, Redpoint Ventures, T. Rowe Price, Lightspeed Venture Partners, Alpine Space Ventures, and others – with an additional $500M in signed contracts across commercial and US government customers – we’re mass-producing the highest-power satellite platforms ever built for missions from LEO to deep space. The rise of heavy-lift launch vehicles is shifting the industry from an era of mass constraint to one of mass abundance, and we believe this new era demands a fundamentally different class of spacecraft. Engineered to survive the harshest radiation environments and to fully capitalize on today’s and tomorrow’s massive rockets, K2 satellites deliver unmatched capability at constellation scale and across multiple orbits. With multiple launches planned through 2026 and 2027, we're Building Bigger to develop the solar system and become a Kardashev Type II (K2) civilization. If you are a motivated individual who thrives in a fast-paced environment and you're excited about contributing to the success of a groundbreaking Series C space startup, we’d love for you to apply. The Role As a Senior GNC engineer, you will be a core driver of the overall spacecraft GNC architecture. You will execute detailed trade studies to find new and novel ways to implement the spacecraft’s orbital guidance, orbital control, and attitude and orbit estimation systems. In the first 3 months, you will support the development/improvement of the MEO navigation, taking lessons learned from the Gravitas mission and applying them to the baseline GNC stack. In the first 6 months you will support the development of new and novel navigation approaches to support future programs – specifically solving navigation for GEO, cis lunar, and interplanetary. In parallel you will support the development of the in-house trajectory design scheme and associated analysis workflow. As we learn more about our system, this will lead to updates to both the GNC stack and the K2 6-DOF simulation. The expectation is that all GNC team members commit code to the 6-DOF sim as well as owning a portion of the GNC flight software. In the first year, you will support launch and on orbit operations of the Trinity mission – the stacked launch of 3 K2 Mega spacecraft. In parallel, you will continue to support improvements, closing the loop on the design, build, test, fly lifecycle. Responsibilities Work with other engineering leads to develop and validate a novel high level vehicle architecture Develop novel algorithms for precise navigation in LEO, MEO, GEO, cis lunar, and interplanetary space. Develop simulation and modeling tools to support vehicle and GNC trade studies. This includes mission design, controls analysis, and 6-DOF simulation development. Contribute to building the GNC organization by recruiting, hiring, and mentoring other engineers Qualifications Experience with implementing estimation algorithms on for flight software and ground software, specifically Kalman Filters, Extended Kalman Filters, and Unscented Kalman Filters Experience performing Monte Carlo based analyses and covariance analysis Experience with verification and validation of GNC flight software in an integrated environment, leveraging 6-DOF simulation and HITL testing. Experience with GNC sensor sizing, selection, and system design Experience with Python, Julia, C/C++, Rust, or Matlab for algorithm development, implementation, and simulation Nice to Have Experience with system identification, leveraging on-orbit data Experience with early-stage spacecraft conceptual design, i.e. “clean sheet” design work Breadth in control algorithm development Experience with reaction wheel, control moment gyroscope, or thruster sizing and algorithm implementation Experience with trajectory ana ... (truncated, view full listing at source)