Performance evaluation of atmospheric density models for satellite reentry predictions with high solar activity levels

In order to estimate the intrinsic accuracy of satellite reentry predictions, the residual lifetimes of eleven spacecraft and five rocket bodies, covering a broad range of inclinations and decaying from orbit in a period of high solar activity, were determined using three different atmospheric density models: JR-71, TD-88 and MSIS-86. For each object, the ballistic coefficient applicable to a specific phase of the flight was obtained by fitting an appropriate set of two-line orbital elements, while the reentry predictions were computed approximately one month, one week and one day before the final orbital decay. No clear correlation between the residual lifetime errors and the satellite inclination or type (spacecraft or rocket body) emerged. JR-71 and MSIS-86 resulted in good agreement, with comparable reentry prediction errors (~10%), semimajor axis residuals and ballistic coefficient estimations. TD-88 exhibited a behaviour consistent with the other two models, but was typically characterised by larger reentry prediction errors (~15-25%) and semimajor axis residuals. At low altitudes (< 250 km) TD-88 systematically overestimated the average atmosphere density (by ~25%) with respect to the other two models.