One of the important feature added with the last two versions of Orekit is the Draper Semi-analytical Satellite Theory (DSST). The initial work was focused on the mean elements equations. These elements have been improved and thorough validation performed. The current status in the forge includes all these refinements. The Orekit team has proposed several papers on upcoming space flight dynamics workshops to describe the validation results obtained and some of the improvements done.
Current work is now focused on two parts: short-periodics terms addition and surface force models extensions. With short periodics terms added, Orekit DSST will match Fortran standalone DSST scope. With surface force models extensions, we hope to go a little step further, adding short periodics also to surface force models (they are not supported in the standalone DSST), and take attitude and spacecraft shape into account (standalone DSST uses only a spherical body model).
This ongoing work is available on the Git repository in the dsst-short-periodics branch, that will be merged into master branch when stable enough.News summary