Overview
LeoDOS uses NASA's NOS3 framework to simulate a satellite constellation on a development machine. The same cFS flight software runs in simulation and in flight — application code is identical in both environments, with only the hardware abstraction layer swapped.
Architecture
The simulation has four layers. Flight software at the top communicates with hardware simulators at the bottom through a bus abstraction layer. NOS Engine replaces physical hardware buses with TCP connections. The diagram shows a single simulated satellite.
↑ same code in simulation and flight — ↓ NOS Engine replaces real hardware
Simulation time is synchronized at 10 μs per tick. NOS Engine distributes the clock to all components. The simulation can run faster or slower than wall clock time.
Sections
- Constellation Simulation — running multiple satellites with Docker, the CLI, and scaling
- Orbital Mechanics — orbit propagation, attitude dynamics, and the space environment
- Sensors and Actuators — attitude, navigation, power, propulsion, and imaging hardware
- Communication — ground links, inter-satellite links, and hardware bus emulation
- Earth Observation — synthetic sensor data for workflow testing