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.

References

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

Retrieved 6/3/2018.

 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.