Hi @MaximeJ ,
Actually, the key point is just the srp force.
@Bryan has pointed that in previous post. https://forum.orekit.org/t/two-bugs-in-orekit-tutorials/1423/3?u=lirw1984
Also, the analysis centers producing Lageos2’s orbit products generally not estimate the reflection coefficient. The value for Lageos2 is well known and equal to 1.13. The reason why we don’t active the solar radiation pressure for the Lageos2 tutorial is because it increases the computation a lot (i.e., ~16sec without SRP, ~69sec with SRP, and ~98sec with estimated SRP) without big improvements in the orbit solution.
While, in v12.0, the performance of srp is improved, so I think that it is acceptable to add srp force.