I understand the mechanics of LEO, and the de-orbit mechanics put in place. But the world-wide impact, unknown side-effects on the upper layers of atmosphere on the re-entry of literally thousands of satellites within fairly short period of time?
SpaceX was the only conceivable launch provider for this, and if it had been an external customer that cares too much about the risk of these launches the incremental improvements that made this cost-effective wouldn't have been possible. Realistically this was only viable for SpaceX doing it as part of R&D for their own rockets. And even then this puts severe financial strain on them because their original business plan was built around having Starship available years ago for even cheaper deployment of bigger satellites
Of course now that it has been done and technology has advanced by ~7 years it is much easier for new mega constellations. But at the time SpaceX started doing it the idea was rightfully called insane
Well, so is satellite launch right? Cost, efficiency, and scaling are hard to do. That's SpaceX's entire raison d'etre. Doing a general public usable all weather maintenance free well designed phased array terminal they can sell for $250 and pump out by the millions is as worthy an achievement as near anything else in the Starlink project. And I'd love if it was more available too even terrestrially, for PtP/PtMP links alignment even motionless is a certain amount of work at long distances. And long range high bandwidth stuff isn't cheap. It'd be pretty cool if you could have units for $250 that you just needed to aim vaguely in the right direction and then it all just worked.
The Starlink terminal is a very cool piece of kit, but it's not nearly as interesting as what they're hucking into LEO, and how they're doing it.
The famous phrase 'Quantity has a quality of its own' comes to mind.
You do value human utility, right?
But in turn the composition of present satellites and the nature of their use/lifespan/safety systems has itself been driven heavily by economics. We don't make satellites out of steel or other safer materials not because they don't work, but because of the cost the extra weight imposes. We haven't put satellites in VLEO not because being lower is bad for communications or imaging (it's the opposite, lower is better) because it'd need more satellites, more fuel per sat, and higher cadence, all increasing cost beyond the historic ROI. But Starship or other future fully reusable methalox designs will give us vastly more mass budget and cadence for the same cost. Some of that could result in more trouble with existing designs made for a low cadence/high $/kg environment, because some externalities that were previously acceptable due to lack of scale stop being so at scale. But the same increased budget also means increased budget to ameliorate that. We can trade some of the gains for materials that burn up harmlessly in the atmosphere, designs for lowering apparent magnitude to the ground, for better self-destruct and end of life systems, more fail-safety, more redundancy in general, etc etc. And if that requires more regularly replacement that too is made easier but order of magnitude or more lower cost.
Some of this may happen naturally just due to self-interest, but other parts like pollution may require thoughtful regulation. But such regulation will be a much easier lift when it's affordable, so it's worth it to try to maintain an appropriately thoughtful mindset on the benefits vs tradeoffs and how to keep the former while reducing the latter.
This appeal to scary ignorance to poop on a technology is a cynical reflex. Instead of just saying that a bare number with no context scares you, you should dig deeper and try to actually back up or invalidate your fears.
You probably could make the same point in a better way as well.
Space dust on the other hand behaves very differently on reentry because of the high surface area to volume ratio.
As for presuming them to be safe, there's fuck all evidence to the contrary. Whining with baseless speculations about the effect of satellites burning up is motivated by the base reflex to shit on any technological progress as an environmental disaster in the making, but nobody can come up with a story about how dolphins might choke on satellites so instead we get this "muh aluminum" narrative.
A 5 years useful lifespan sets the replacement rate and thus the average number burning up each year. In steady state the delta between end of life and reentry is irrelevant, instead the average number of satellites launched each year = average number that burn up each year.
As to harm. Aluminum is mildly toxic, you don’t eat your bike but vaporized aluminum from a satellite is way more likely to cause harm than if the things were made of steel. The plastic bits are likely fine though.
Saying let’s study something ahead of time rather than contaminating all the world’s farmland with and then seeing what happens seems like a perfectly reasonable standard. Technology has generally been wonderful, but that doesn’t mean everything is equivalent. We want to phase out leaded aviation fuel in the US even though it’s ‘only’ 2,000 tons of lead per year, that’s still enough to be problematic. Perhaps ramping up to ~5k tons/y of vaporized aluminum worldwide is a complete non issue, but if it’s not insisting on some other material isn’t the same as a ban.
If Starlink’s are about 2 tons each (the v3’s are going to be much larger) and they each have a roughly 5 year life span and the 10,000 currently are equally spread over that lifespan (so around 2,000 a year need to be replaced) that’s equivalent to around 10 tons per day of Starlink material breaking up in the atmosphere.
With the 1 million SpaceX datacenters Musk talks about and an original projected satellite Starlink swarm size of 40,000, that number balloons to something like 500 tons per day.
So while today it is only a fraction of the total amount of material breaking up in the atmosphere, the idea that multiple companies could have Starlink size satellite swarms with lifespans measured in a few years we start to easily dwarf what meteorites do.