DSST propagator with small eccentricities

[bcazabonne]

Hi @ShikaDing

Maybe I’m wrong but I don’t think it is issue.
I would recommend you to look at Luc’s answer on the following post. Especially the figure with the 8-shape.

Question about argument of perigee

Hi @bdruby, welcome onboard Your observation is correct, and it is a normal behaviour. Many angles in space flight dynamics can evolve over time without limitation. True/Mean/Eccentric anomaly is the best example. When computing Keplerian elements from Cartesian elements, the algorithm used in Orekit is to compute the orbital plane (which is orthogonal to to orbital momentum given by the cross product of position and velocity), then to compute the semi major axis using equation of energy which…

To summarize a mean eccentricity of 0.0 does not involve an osculating eccentricity of 0.0.

Best regards,
Bryan