Specifically i think starlink satellites do not have any boosting thrusters, the reason important LEO satellites like the ISS don't burn up unless intended is due to those
starlink satellites do not have any boosting thrusters
Starlink satellites actually do have Hall-effect ion thrusters, and can raise and lower their their own orbits. Though like any spacecraft, they still have a finite amount of fuel and will eventually deorbit.
Fine powder of metals strewn over a few km², there's more coming from outer space via micrometeorites and dust. And that bit CO² in the Stratosphere...
I don't think they need much fuel in this case unless they want to be absolutely sure that they deorbit in the right place. The satellites are so small that might not even be needed.
Yes, it takes little fuel to destabilize one's orbit and eventually enter the atmosphere to burn up. It's more difficult if you need to make sure that the craft doesn't take others down during the procedure.