Impact of the ballistic coefficient estimation on orbital lifetime predictions of rocket bodies

One essential aspect of the Inter-Agency Space Debris Coordination Committee (IADC) space debris mitigation guidelines is the clearance from the protected regions at the end of the mission. More specifically, for the Low Earth Orbit (LEO) region, the orbital lifetime shall not exceed 25 years after the end of mission. Furthermore, the Federal Communications Commission (FCC) has lowered this limit to 5 years for all spacecraft under their jurisdiction, and the European Space Agency has already announced plans to follow a similar path with their Zero Debris policy. In this context, accurate orbital lifetime estimations become even more essential to assess the compliance of new missions to  be launched, as well as to adequately assess the current state of the environment.
The decay of objects in LEO is mainly dominated by drag, caused by the residual atmosphere in these lower altitudes. Consequently, the modelling of the ballistic coefficient has a great impact on the predicted orbital lifetime. RACER (Radiation and Atmospheric Drag Coefficient Estimation Routine) is a tool by the European Space Agency that estimates the ballistic coefficient of an object based on a set of Two-Line Elements (TLEs). This ballistic coefficient can be used to improve current orbital lifetime predictions.
In this paper, the results obtained from the estimation of the ballistic coefficient using RACER are analyzed, aiming to understand the different parameters that affect its evolution and to identify patterns corresponding to similar objects. Additionally, different methodologies are investigated, which make use of these results to improve the orbital lifetime estimations for a set of rocket stages.