Principal Modeling and Simulations Engineer Broomfield, Colorado

Principal Modeling and Simulations Engineer Katalyst Description

We build robotic spacecraft that enable dynamic space operations, creating a future where maneuvering, upgrading, refueling, and exploration are as routine as they are on Earth. Getting to space and overcoming the gravity well is only half the story. What you do there is the future. We are not building the trains. We are building the machines that lay down the tracks.

By developing the foundational capabilities that make sustained, responsive operations possible, we enable a new era of space activity that strengthens national security and ensures freedom of action in an increasingly contested domain.

Working at Katalyst is intense, hands‑on, and deeply rewarding. You’ll take real ownership and see your work move from concept to operations in an environment where the problems are hard and the impact is real. We value humility, craftsmanship, and doing things the right way, even when it’s harder. You’ll work closely with thoughtful, driven teammates who push each other to do their best.

• Understand spacecraft architecture and missions
• Review current model and simulation capability
• Identify any gaps in current simulation framework
• Evaluate how simulation integrates with other teams within the company GSW, FSW, AI&T, MOPS, etc.
• Train as an operator to prepare for upcoming mission
• Identify gaps from assessment and create the simulation architecture roadmap
• Identify required models (Spacecraft subsystem, environment, GNC, etc.)
• Establish a framework that defines how hardware models, software models, and operational scenarios interact within the simulation environment
• Establish how the digital twin gets integrated into a physics‑based "universe sim"
• Establish a concrete validation strategy

• Systems level thinker understanding the crossroads of physics, software, and hardware
• Ownership mindset serving as the technical authority across design and implementation
• Ability to prioritize needs from multiple internal and external customers
• Excels while operating in a fast‑paced New Space environment
• Strong desire to build and design something from the ground up
• Someone willing to get dirty and produce code, not just design
• Passionate about creating a product that is used throughout the company

• Strong understanding of orbital mechanics and astrodynamics
• Experience modeling spacecraft dynamics, control systems, and environmental effects
• Ability to design modular and extensible simulation architecture
• Experience implementing physics‑based simulations in Python and C++
• Strong knowledge of numerical methods, time integration, and stability considerations
• Experience building "universe‑style" multi‑body simulation environments
• Ability to design simulations that support historical replay, real‑time execution, and accelerated future‑time scenarios
• Experience with integrating simulations with GSW, FSW, AI&T, and HITL testing
• Ability to design constellation level simulations
• Experience designing event‑driven or time‑stepped simulation frameworks
• Experience generating realistic synthetic telemetry
• Strong V&V practices

• 10+ years of experience in modeling and simulation for complex aerospace missions
• Deep understanding of physics engines or digital twins (subsystem/component models, dynamical systems, etc.)
• Experience developing for multiple internal stakeholders such as AI&T, GSW, MOPS, FSW, etc.
• BS in Aerospace Engineering, Physics, Computer Science or closely related STEM field
• Deep knowledge in C++, Python, Basilisk (or similar framework), Docker, K8, CI/CD

• Proven ownership of the design and architecture of a multi‑model and simulation system
• Understanding of distributed simulation frameworks
• Strong foundation in multiple subsystems such as GNC, Flight Dynamics, EPS, Propulsion, etc.
• Nice to have experience simulating 6‑DOF relative motion and ROPD missions

Must be willing to work extended hours and weekends as needed.

Your base salary will be determined on a case‑by‑case basis and may vary based on the following considerations: job‑related knowledge and skills,…