Q 3.8 Is it possible to predict the orbital lifetime of a satellite?
The physical lifetime of space object is predicted by its initial satellite orbital parameters, the object’s mass to cross-sectional area in the direction of travel and estimates of the upper atmospheric density which affects the drag on the object [Ref 3.8-1]. The upper atmospheric density is affected by solar flux and magnetosphere.
Due to random variability associated to these parameters, prediction of orbital life-time tends to have a residual error of about 10% at best (Ref 3.8-2). The location of a probable crash is generally obtained by real time tracking in the last few hours of the re-entry and its extrapolation. As an illustration, a 100 kg satellite of 1 m2 area at 300 km would theoretically take about 46 days to enter the threshold altitude of around 180 km [Ref 3.8-1] from which it would typically take a few hours to burn out except if the object is large, e.g., where its mass to area ratio exceeds 100 kg/m2.
Depending on the orbital parameter, satellite mass and area, the space weather re-entry time from a given orbit to the threshold altitude can vary from a few days to months and years.
Objects at altitudes, less than around 500 km tend to lose height rather quickly due to an increase in drag below this altitude.
3.8-1 The Australian space weather agency, Determination of orbital life time, (updated by Rakesh Parmar). Available: http://www.sws.bom.gov.au/Category/Educational/Space%20Weather/Space%20Weather%20Effects/SatelliteOrbitalDecayCalculations.pdf
3.8-2 King-He1e, D. G. “Methods for Predieting Sate11ite Orbita1 Lifetimes”,
J. of the Bntish Interplan. Soc., Vol. 31, 1978, pp. 181-196.