This may be a silly question, but when it's said that these are not in a "stable orbit", what is the mechanism of decay? I'd imagine if they were in an elliptical orbit, they'd simply continue that way forever in a "perfect" system. I'd imagine tidal forces would be too weak and the satellites too small for them to have any effect.
Are they passing through the atmosphere and experiencing atmospheric drag?
Are they passing through the atmosphere and experiencing atmospheric drag?