I know folks on here have a love / hate relationship but I think this would benefit from moving to cloudflare's stack. Current server is completely dead (has a Hostinger IP so they probably took it down from the traffic spike)
I'm Davi, a 17-year-old developer from Brazil, and I've spent the last few months building NEO Radar, a browser-based orbital mechanics engine focused on Near-Earth Objects.
The goal wasn't to build another Solar System viewer, but to understand how orbital propagation actually works and implement as much of it as I could from first principles.
Some highlights:
• 41,812 real asteroids from the Minor Planet Center • JPL Horizons ephemerides • Newton-Raphson solver for Kepler's equation • Adaptive RK4 N-body integration • Monte Carlo uncertainty propagation • Real planetary perturbations • Interactive 2D heliocentric visualization
One architectural decision I'm particularly happy with is that the physics engine is completely isolated from rendering. The integrator has no DOM, Canvas or fetch dependencies—it simply outputs state vectors that the renderer consumes.
The repository also includes benchmarks, unit tests and documentation describing the numerical methods and the limitations of the model.
This project taught me far more about numerical methods and orbital mechanics than I expected when I started.
I'd really appreciate feedback, especially from anyone with experience in astrodynamics, numerical simulation or scientific visualization. I'm sure there are many things that can still be improved.
Eg I see you've got an adaptive Runge-Kutta method implemented in integrator.js. While that will do really well the purpose of this project is to learn - maybe you could make the solver implementation swappable, to experiment with and gain understanding of the different techniques. Some are very slow. Some maybe unstable and blow up the solar system. Why? Numeric methods are not one size fits all - see what the different tradeoffs are and how they respond to fiddling parameters.
Usually you learn more in the second half than the first. The first just makes the second half feasible. Not that there is anything wrong with just wanting to make another visualizer and learn some things along the way, it's just a hollow way to try to learn first principles by itself.