Initialization of DSST short period terms

Hello everyone,

I’ve got a question. With the DSST model, if a propagation is performed, the method initializeShortPeriodTerms is used, for each “force”, only in the method beforeIntegration, which is called only sparsely I’m guessing. Meanwhile, the static method to convert from mean to osculating calls (based on a fixed point algorithm), calls it at each iteration. Wouldn’t be possible to call it only once, before the loop?
If yes, an even better solution performance-wise would be to have a public static method able to take already initialized forces as input.


Hi @Serrof,

You meant “osculating to mean” right?

I was inclined to say yes at first, but the short-period terms depend on the mean orbit we are trying to compute in the fixed-point algorithm loop.
If they were fixed then we wouldn’t have to perform the fixed point to begin with, we would just do the inverse of what is done in computeOsculatingOrbit. Am I wrong?


Thanks for your reply Maxime. The thing is that if one needs to call initializeShortPeriods each time the mean orbit changes, shouldn’t one call it in afterPropagation and actually even after each integration step?