The idea

I've spent a lot of time working with telemetry systems and real-time data pipelines professionally. sim-sat started as a way to explore those same patterns without any of the constraints that come with a work environment. Orbital mechanics, live data streaming, 3D visualization. Just me building something I find genuinely interesting.

How it's structured

It's a Turborepo monorepo with pnpm workspaces. The frontend is React + React Three Fiber and the backend is Express with Socket.IO. Shared types live in a @sim-sat/shared package that both sides import, which keeps the data contracts clean without duplication.

The 3D view renders live orbital positions. The backend streams telemetry over WebSockets and the frontend resolves the shared package directly from source via a Vite path alias, so there's no extra build step during development.

At build time the frontend pulls current TLE satellite data from Celestrak and bakes it in, so the 3D view has real orbital data without needing a network call at runtime.

Status

Still actively working on it.