Space weather, Earth´s neutral upper atmosphere (thermosphere), and spacecraft orbital lifetime/dynamics

Accurate prediction of a spacecraft/satellite orbital lifetime, insertion altitude, reboost requirements, and mission performance is mainly the result of the integrated effect from knowledge of the atmospheric density, space weather (solar/geomagnetic), and timeline of vehicle characteristics. Each of these elements is dependent upon a model developed to provide the inputs necessary for the use of an orbital lifetime prediction program. This paper will address relative influences of these elements with emphasis on solar/geomagnetic activity, atmospheric density, and drag coefficient associated with the model products used to predict orbital lifetime and related spacecraft/satellite design and operational conditions. Issues associated with the potential for improvement of the lifetime prediction model input elements will be discussed with regard to their relative contributions to improving orbital lifetime and performance predictions