Starlink is all in LEO. It doesn’t become space junk as there is sufficient drag in LEO that they readily deorbit purely due to air resistance (yes, there is enough air in LEO to make air resistance the factor in why Starlink does not become space junk).
And as far as passive deorbit times, this chart is for a 1u cubesat, and bigger satellites would come down faster, but it illustrates some of the point that Starlink isn’t actually the problem here:
Starlink is all in LEO. It doesn’t become space junk as there is sufficient drag in LEO that they readily deorbit purely due to air resistance (yes, there is enough air in LEO to make air resistance the factor in why Starlink does not become space junk).
Let’s put actual numbers on it:
Starlink: 500-570km
Kuiper: 630km
Guowang: 900-1145 km
And as far as passive deorbit times, this chart is for a 1u cubesat, and bigger satellites would come down faster, but it illustrates some of the point that Starlink isn’t actually the problem here:
The ballistic coefficient, mass divided by cross section area, still determines how drag effects trajectory in the LEO environment.
It should be pretty straightforward to extrapolate if you know the relevant parameters on both spacecraft.
The outer shell of the Guowang constellation on the other hand…