These would be placed in a relatively high LEO of 800 & 950km, 20 satellites per plane on 18 orbital planes (likely 18 launches, but a remote possibility is usi

These would be placed in a relatively high LEO of 800 & 950km, 20 satellites per plane on 18 orbital planes (likely 18 launches, but a remote possibility is using a bunch of fuel over multiple maneuvers to do 9 or 6). Orbital lifetimes to Earth decay according to altitude are highly variable, especially with the form factor of the satellite and its mass & profile against the remnant atmosphere, but for typical satellites very, very roughly: 150km minutes to hours 300km days to weeks 450km months to years 600km years to decades 750km decades to centuries 900km centuries to millennia 35,786km (GSO) effectively unlimited Something this high would indeed pose an addition to the Kessler threat by virtue of remaining up there for many doublings of debris density; And redressing that would not be so difficult, in actuality. Chemical deorbit, ion deorbit, electromagnetic tether deorbit, and sail deorbit are all possibilities; The last does not even require orientation control. All that's needed is some incentive for them to implement controlled deorbitting.