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Here's a simulation to answer your question: Would we not expect to have a seen a greater decay than what has occurred so far? Answer: no. The simulation includes the Newtonian and the relativistic accelerations of all the planets, Sun and Moon. The Earth's gravity field is modeled with the SGG-UGM-1 gravity model (computed using EGM2008 derived gravity ...

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This additional answer is just to show the effect of the solar activity on the decay rate. The graphs were obtained from 15279 TLEs downloaded from https://celestrak.com/NORAD/archives/request.php processed with the CSpOC's SGP4 library freely downloadable from www.space-track.org. The following graph shows the mean radius vector and the mean air density (...

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In this supplementary answer I've crudely processed all TLEs for Vanguard 1 and plotted the trends. I used the mean motion (revs/day) to get a period, divided by 0.9975 (estimating from this answer) to undo the effects of $J_2$, then used $a^3=GM (T/2 \pi)^2$ to estimate a semimajor axis, periapsis and apoapsis based on the TLE's eccentricity value. This is ...

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Because it's using Earth's magnetic field to create drag. It's one of several passive deorbiting systems. An electromagnetic tether uses a conductive tether to generate an electromagnetic force as the tether system moves relative to Earth’s magnetic field. NASA: State of the Art of Small Spacecraft Technology, 12. Passive Deorbit Systems In-Space ...

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Removing debris costs money. Even with many words like "efficient", "low-cost", and so forth, a system capable of removing a significant amount of space debris still involves a budget requirement containing a large number of digits. For other space programs, the motivation for the large sums of money spent is a gain of some sort. Scientific data, military ...

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