orts

Numerical computation and optimization platform for orbital mechanics.

Rust workspace for orbital / attitude simulation with a React-based real-time 3D viewer, WebAssembly Component Model plugin runtime, and browser-native analytics.

Features

• N-body orbital simulation with adaptive (DOP853, Dormand-Prince) and symplectic (Störmer-Verlet, Yoshida) integrators
• Gravity models: point-mass, spherical harmonics (up to degree 16)
• Perturbations: atmospheric drag, solar radiation pressure, third-body gravity, constant thrust
• Atmosphere models: Exponential, Harris-Priester, NRLMSISE-00
• Geomagnetic field: IGRF-14 spherical harmonic expansion + tilted-dipole approximation
• Space weather: CSSI and GFZ providers (F10.7, Ap, Kp)
• IAU 2006/2000A CIO-based Earth rotation with typed coordinate frames and EOP
• Celestial body ephemerides (Meeus analytic + JPL Horizons)
• Attitude dynamics and control: reaction wheels, magnetorquers, B-dot / PD controllers
• Sensor models: magnetometer, gyroscope, star tracker (with noise)
• WASM Component Model plugin runtime for guest controllers via wasmtime
• CLI with embedded 3D viewer, WebSocket telemetry, and format conversion
• Real-time charting with DuckDB-wasm + uPlot (uneri library)
• Rerun .rrd data format for recording and replay

Installation

# From source
cargo install orts-cli

# Pre-built binary (cargo-binstall)
cargo binstall orts-cli

Quick Start

# Run a simulation from config file
orts run --config simulation.toml

# WebSocket server with embedded 3D viewer
orts serve --config simulation.toml
# Open http://localhost:9001

# Replay a recorded simulation
orts replay output.rrd

# Convert between formats
orts convert output.rrd --format csv

Example config (simulation.toml):

body = "earth"
dt = 0.01
duration = 120.0

[[satellites]]
id = "sat-1"
sensors = ["gyroscope", "star_tracker"]

[satellites.orbit]
type = "circular"
altitude = 400

[satellites.attitude]
inertia_diag = [10, 10, 10]
mass = 500

[satellites.reaction_wheels]
type = "three_axis"
inertia = 0.01
max_torque = 0.5

See examples/ for Apollo 11, Artemis 1, orbital lifetime analysis, and WASM plugin demos.

Project Structure

Rust crates

Crate	Directory	Description
orts	orts/	Core simulation: dynamics, force/torque models, sensors, plugin host
orts-cli	cli/	CLI binary with embedded viewer + WebSocket server
orts-plugin-sdk	plugin-sdk/	SDK for writing WASM plugin guest controllers
arika (在処)	arika/	Coordinate frames, epochs, Earth rotation, ephemerides
utsuroi (移ろい)	utsuroi/	ODE integrators (RK4, DOP853, Störmer-Verlet, Yoshida)
tobari (帳)	tobari/	Atmosphere density, IGRF geomagnetic field, space weather
rrd-wasm	rrd-wasm/	Rerun RRD decoder compiled to WebAssembly

TypeScript / npm packages

Package	Directory	Description
uneri (うねり)	uneri/	DuckDB-wasm + uPlot streaming time-series charts
orts-viewer	viewer/	Real-time 3D orbit viewer (React + @react-three/fiber)
starlight-rustdoc	starlight-rustdoc/	Astro/Starlight plugin for Rust API docs from rustdoc JSON

Example plugins

Plugin	Style	Description
bdot-finite-diff	main-loop	B-dot detumbling via finite-difference dB/dt
pd-rw-control	callback	PD attitude control + reaction wheels
pd-rw-unloading	callback	PD control + magnetorquer RW unloading
detumble-nadir	callback	Detumble → nadir pointing mode transition

Documentation

• Docs site — API reference, examples, guides
• DESIGN.md — Design document (Japanese)
• CHANGELOG.md — English changelog
• CHANGELOG.ja.md — Japanese changelog
• RELEASING.md — Release process

License

MIT