13:33 <queqiao-> ⟨kuzinat0r⟩ https://matrix.mockingbirdnest.com/_matrix/media/r0/download/matrix.mockingbirdnest.com/LlsjzlrKlvaqTKFGhgSjQdHd/image.png

13:33 <queqiao-> ⟨kuzinat0r⟩ What makes my molniya orbit unstable? I have 3 other satellites on very similar orbits and they don't lose altitude

13:52 <queqiao-> ⟨test_account9540⟩ Maybe periapsis is too low. If you had a higher periapsis, this orbit variation wouldn't lead to collision 🤔

13:53 <queqiao-> ⟨nazfib⟩ Could be some unfortunate interaction with the Moon and/or Sun, where it happens to pull you retrograde right at apogee.

13:54 <queqiao-> ⟨nazfib⟩ +EDIT: actually, no; that would reduce your semi-major axis, which does not change in that screenshot.

14:03 <queqiao-> ⟨nazfib⟩ +Maybe it's related to the [von Zeipel-Kozai-Lidov](https://en.wikipedia.org/wiki/Kozai_mechanism) effect?

14:23 <queqiao-> ⟨kuzinat0r⟩ it's 500 km. Should be high enough)

14:27 <queqiao-> ⟨test_account9540⟩ Google search leads here, the content is incomprehensible, may or may not be relevant

14:27 <queqiao-> https://www.sciencedirect.com/science/article/abs/pii/S0273117714002178

14:27 <queqiao-> ⟨test_account9540⟩ it's also not available for free

14:29 <queqiao-> ⟨test_account9540⟩ might be better https://conference.sdo.esoc.esa.int/proceedings/sdc5/paper/49

14:30 <queqiao-> ⟨test_account9540⟩ the conclusion says:

14:30 <queqiao-> "It is find out, that the major factor influencing the lifetime of a space vehicle in an orbit is the gravitational attraction from the Moon and the Sun. The lifetime of SC “Molniya” depends on the initial values of the longitude of ascending node and also on the value of argument of perigee & of an orbit. "

22:24 <queqiao-> ⟨egg⟩ Third body effects don't normally change the semimajor axis. I suspect лидов–古在 too.

22:25 <queqiao-> ⟨egg⟩ Also, I ought to rename the relevant test to mention von Zeipel (I remember seeing the effect with three names in Nature a while back)