There can be a world of difference between designing an orbit using Orbital Elements and how the satellite’s orbit truly is. The reason is fairly obvious, Orbital Elements only account for the one force, the gravity of the object that the satellite is orbiting around. In the real world, there are many other forces at play, which need to be considered.
SOS tries to allow for these forces, as much as it practically can. Some forces are quite trivial to account for. For instance, the Earth’s bulge (due to its spin), has been mathematically modelled and can be accounted for. The Moon’s gravity is not hard either. Other forces, such as Solar Pressure and Atmospheric Drag, require knowledge of the satellite in question, but SOS has mathematical models for these too. Unfortunately, these models can not account for the day to day Solar Weather. This can lead to several effects like causing more atmospheric drag than predicted. SpaceX had this very problem when launching a batch of satellites in February 2022. It lost 38 of 49 satellites due to a geomagnetic storm – see link for more details. Fortunately, these instances are quite rare and any unforeseen forces like these can be picked up and allowed for using normal orbit maintenance manoeuvres.
