I am looking for the precise algorithms/calculations/formula used by orekit (I want to understand the math and the physic behind functions, especially in propagation), and I don’t find it in the documentation. Do you know if I can access to these information ?
Most of the frames follow IERS TN 36. Montenbruck & Gill is a good reference or any other astrodynamics text book is a good reference. There isn’t a comprehensive document specifically about Orekit. Though you’re welcome to take on that task.