Instead of users (e.g., independent owners/operators of different satellites) having to calculate orbit determination for each satellite themselves, an orbit determination service automatically calculates the orbit determination (OD) based on a user request. The calculated OD can then be used by a satellite ground station service to determine appropriate orientations for a ground station antenna in order to communicate with the satellite. In some embodiments, the OD service uses information from the calculations of ODs for multiple satellites and users to update a model used in the OD calculation, for example, to provide a more accurate model for Earth's atmosphere to be applied in subsequent OD calculations. In some embodiments, the OD service uses a user-provided computer-aided drawing (CAD) file of the satellite to produce or tune models specific to the satellite, for example, to generate more accurate models for solar radiation pressure and ballistic drag.