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What is Basilisk?

Basilisk (BSK) is a fast, open-source spacecraft-centric mission simulation framework developed jointly by the University of Colorado AVS Lab and the Laboratory for Atmospheric and Space Physics (LASP). The framework provides a modular collection of spacecraft simulation building blocks written in C/C++ with a Python scripting interface. Think of it as a set of spacecraft “lego blocks” — pre-validated, reusable modules that you assemble into complete mission simulations.

Quick Install

Install via PyPI in one command and run your first simulation in minutes.

Quickstart Tutorial

Step-by-step guide to setting up a basic orbital simulation.

Core Concepts

Understand the modular architecture and message-passing interface.

Examples

Explore over 100 integrated simulation scenarios.

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Key capabilities

Faster-than-realtime simulation

C/C++ execution with Python scripting enables simulating a mission year in under a day for 6-DOF dynamics.

Modular architecture

Swap, extend, and reconfigure simulation components without impacting the rest of your simulation.

Monte Carlo engine

Built-in bit-for-bit repeatable Monte Carlo capability with configurable distribution functions.

Hardware-in-the-loop

Real-time synchronization support for HIL testing with actual flight hardware.

Rich FSW library

Pre-built attitude determination, guidance, and control algorithms ready to use.

3D Visualization

Companion Vizard application provides interactive 3D visualization of spacecraft and orbits.

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What Basilisk is used for

  • Astrodynamics research modeling complex spacecraft dynamical behaviors
  • Developing and validating new guidance, estimation, and control solutions
  • Supporting mission concept development and flight software design
  • Hardware-in-the-loop testing by simulating spacecraft states in real time
  • Analysis of flight data compared against expected behavior
  • Spacecraft AI-based autonomy development

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Architecture overview

Basilisk simulations are composed of modules that communicate through a message-passing interface (MPI). Each module has defined input and output message connections — connecting these creates the full spacecraft simulation. 
[Gravity Effector] ──► [Spacecraft] ──► [Navigation Filter]
                           │
                    [Reaction Wheels] ──► [MRP Feedback Controller]
                           │
                    [Thruster Effector]
The Python layer uses SWIG to expose the C/C++ modules, giving you full scripting control over task rates, model parameters, and output configuration without recompiling.

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Getting started

1

Install Basilisk

Install the prebuilt wheel from PyPI:
pip install bsk
2

Download examples

Get all tutorial scripts locally:
bskExamples
3

Run your first simulation

python scenarioBasicOrbit.py
See the Installation guide for platform-specific details and advanced options.

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Platforms

Basilisk runs on macOS, Linux, and Windows. Prebuilt wheels are available for Python 3.9–3.14.

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License

Basilisk is released under the ISC open-source license.

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