Guidance, Navigation & Control (GNC) Simulation Software Engineer

Halcyon Labs builds advanced satellites for high orbits, expanding humanity’s reach into the solar system. Today, Halcyon Labs satellites provide dedicated, secure networks to highly-sophisticated customers across the globe— large enterprises, sovereign governments, and the US military. With five satellites on orbit and many more set to launch soon, the company is servicing a backlog of more than $1 billion of commercial contracts. Halcyon Labs is the preferred satellite communications partner for buyers with stringent requirements for uptime, data security, network visibility, and customization. Halcyon Labs has raised over $750 million from some of the world’s best investors, from Andreessen Horowitz to Blackrock and Fidelity, and employs a team of 450 engineers and entrepreneurs. Halcyon Labs designs, builds, and operates its satellites out of its 153,000 sq. ft. headquarters in Northern California, USA. Guidance, Navigation & Control (GNC) Simulation Software Engineer As a Simulation Software Engineer on the GNC team, you will design, develop, and test our high-fidelity spacecraft simulation that is used to validate the software that controls our satellites while in orbit. You will improve the core simulation infrastructure and collaborate with engineering teams across the company to model new systems and add interesting new features to the simulator. Role Design, develop, and maintain software for our high-fidelity software simulation platform Implement and improve software- and hardware-in-the-loop simulations to validate satellite software and flight algorithms Accelerate the software development process through infrastructure improvements Develop and enhance Monte Carlo simulation tooling for assessing system performance under various conditions Incorporate physics-based models into simulation Develop analysis and visualization tooling to provide insight into our system Support GNC operations for our fleet of satellites, including on-console and on-call rotations Support in recruiting, interviewing, and hiring additional teammates to our rapidly-growing team Requirements BS or MS in Computer Science, Aerospace Engineering, or equivalent background experience 2-5+ years in software or building simulations of complex physical systems 2-5+ years experience with Python or other high-level object-oriented programming language(s) Ability to effectively collaborate with interdisciplinary teams on large software projects Strong problem-solving skills and attention to detail Highly motivated, self-starting, and able to perform duties autonomously without much supervision Don't meet them all? Not a problem. Please apply even if you do not meet all these criteria. Bonus Understanding of classical or modern control theory, and basic orbital mechanics Knowledge of memory management, threading, and interprocess communication techniques Experience building and maintaining software infrastructure used across teams Experience in statistical analysis techniques and Monte Carlo simulation Experience with C/C++ Experience with AI tooling and agentic workflows Experience with databases Experience with spacecraft design What we offer: All our positions offer a compensation package that includes equity and robust benefits. Base pay is just one component of Halcyon Labs’s total rewards package. Your compensation also includes a significant equity package via incentive stock options, high-quality company-subsidized healthcare, disability and life insurance, 401(k) retirement planning, flexible PTO, and free on-site catered meals. Halcyon Labs pay ranges are informed and defined through professional-grade salary surveys and compensation data sources. The actual base salary offered to a successful candidate will additionally be influenced by a variety of factors including experience, credentials & certifications, educational attainment, skill level requirements, and the level and scope of the position. Base Salary $120,000 — $175,000 USD U.S. Citizenship, Lawful Permanent Residency, or Refugee/Asylee Status Required (To comply with U.S. Government space technology export regulations, applicant must be a U.S. citizen, lawful permanent resident of the United States, or other protected individual as defined by 8 U.S.C. 1324b(a)(3)) Our mission and our products are meant to connect the world and everyone in it, regardless of gender, race, creed, or any other distinction. We believe in a diverse and inclusive workplace, and we encourage all people to join our team and bring their unique perspective to help make us stronger.