I am still in this rabbit hole, learning a bunch of new #numerical methods.

What I want at the end is *thrust* acceleration values recovered from satellite position and velocity data given at 1m intervals.

Any method will obviously also have the acc due to gravity and other effects. Methods will differ in how much numerical "noise" they add to the process.

Subtracting the Earth is easy with F=ma=GMm/r^2.

To compare the noise, I'm using a smooth #keplerian element set that has no thrusts.