Switching to steel means satellites don't demise and hit the ground in larger chunks, something that the FCC has actively avoided in their constellation licensing for fear of hitting things.
For example the 4 reaction control wheels for attitude adjustment where you actually want mass, were specifically moved to Al on starlink so that they _would_ burn up on reentry.
I don't know how you weigh the risk of environmental effects vs occasionally landing a sat on something, or someone. I guess an actuary somewhere has a table for that.
I would think it depends heavily on the degree of control they have over where it lands, which is perhaps something that could be optimized for?
I still think it’s a political non-starter, though. People will be terrified of being randomly struck with a satellite, and it would be an enormous international crisis if an American satellite deorbited and took out a skyscraper in Beijing or vice versa. Heaven forbid one accidentally hits the Pentagon or similar, it would probably start world war 3.
It would be interesting to see if the current constellation reentries are in any way grouped over specific areas. My understanding is spacex don't have exact control due to the relative weakness of the ion thrusters and the unpredictability of aerodynamic drag on the big flat surfaces (1). Say only 1% of reentries were completely uncontrolled and random then you're right, that could shift the odds from just acceptable to meh. (1/10.000 -> 1/1.000.000)
For example the 4 reaction control wheels for attitude adjustment where you actually want mass, were specifically moved to Al on starlink so that they _would_ burn up on reentry.
I don't know how you weigh the risk of environmental effects vs occasionally landing a sat on something, or someone. I guess an actuary somewhere has a table for that.