[ddahlen]

It is neat to see some of the old work done in the field, this looks like a pretty classic treatment of the topic. It looks like they were using a fourth-order Runge-Kutta integrator, which would likely limit long term integrations accuracy (though looks sufficient for their use case). Many algorithms I have seen typically use much higher order integration methods to beat down the accumulation of numerical error.

Source: Working on my PhD in orbital mechanics of asteroids/comets, here are my open source (python/rust) orbital integration tools: https://github.com/dahlend/kete

[keepamovin]

That is cool! I encourage you to post as a Show HN with a comment explaining more if you want

[wiz21c]

I'm interested. Could you give examples ?

[ddahlen]

https://www.cambridge.org/core/journals/international-astron...

Here is a heavily used method in astronomy, this involves a higher order polynomial expansion than RK4.

This method has been extended a few times, my code uses a variation of it, and I know of several other projects which are also descended from it.