Asking from a place of ignorance on my part, but does the chemical composition of the satellites versus asteroids/dust have any adverse effects?
This source[0] says satellite reentries are about about 12% of the space industry's contribution to ozone depletion (the big one is chlorine from solid rockets), which in turn is 0.1% of the entire anthropogenic contribution; i.e. satellite reentries are ~0.01% of the total.
https://www.space.com/spacex-starlink-reentry-pollution-dama...
>0.01% of anthropogenic ozone depletion
Satellite reentries in 2022 (ie mostly pre-megaconstellation) were already raising stratospheric AlO levels by 29.5% above normal levels (with satellites adding 'only' 17 t/year), but megaconstellations could raise that to ~480% above natural levels (360 t/year).
This isn't a rounding error, it's a non-trivial change in chemical composition across the entire globe, and effecting a complex and poorly-understood part of the climate system. What could go wrong?
What else can this effect (as usual, discovered belatedly) beyond ozone? Hopefully it's nothing! But I guess we're gonna find out...
[0] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL10...
Those findings are simulated, not observed. Hence "potential."
> it's a non-trivial change in chemical composition over the entire globe, and effecting a complex and poorly-understood part of the climate system. What could go wrong?
Perhaps a lot. Perhaps not much. It's a good question to study. But if this is an issue, it's solvable--carbon composite satellite structures could use a boost in demand and funding.
Of all the megaconstellations, SpaceX has historically been the best at being a "good neighbor," with low orbits for debris and lots of engineering to reduce brightness.[0] But hype around SpaceX gives the real bad actors a pass, for example AST is much worse on brightness,[1] and OneWeb and Qianfan are much worse on debris risk.[2]
[0] https://www.youtube.com/watch?v=MNc5yCYth5E&t=1717s
[1] https://spacenews.com/astronomers-raise-interference-concern...
[2] https://spacenews.com/chinas-megaconstellation-launches-coul...
Starlink is easily one of my favorite engineering projects. I don't believe anybody has done it cheaper, better, or at wider scale than Starlink has.
Better than gates' effort to eradicate malaria?
Sorry to be snarky, but to me Starlink is something rich people in rural England have, because it's slightly easier than paying OpenReach to connect them to proper network. And it's hard to imagine anyone else being their clients, at the prices that they charge.
That claim does not exclude Gate’s projects or any other as being superior. You’re looking for conflict that isn’t there.
Starlink is used all over the world, by regional governments, NGOs and companies where it’s too expensive for individuals.
You might well find that rich English people are subsidizing the project for poorer people elsewhere.
Not to diminish Gates’ malaria efforts, but remote villages having access to information about malaria and prevention methods could be helpful. Along with techniques for filtering water, etc. Access to telehealth.
Yeah, so our perspectives may differ a bit. My personal focus has primarily been with Africa, where Starlink is truly transformative. Demand for Starlink may be underwhelming in developed countries (such as your "rural England" example), while in underdeveloped countries, the demand regularly outstrips the supply [0]. I love that it's affordable enough for my African colleagues to use. In the last couple of weeks, I've had more than one full-motion screen-sharing video call to northern Nigeria (I.E., not the capital city) to do collaborative engineering. Even just a handful of years ago, this would not have been possible before Starlink was available.
I'm not casting any shade on malaria eradication -- that is awesome as well. I can love both things, but the subject here is Starlink, and I want to underscore how truly impressive and effective Starlink has been for advancing infrastructure in a quantum leap.
Improving African infrastructure has been an extremely difficult problem for a very long time (for a quagmire of reasons -- regulatory, power, cost, distribution, etc etc etc). I think most people in the developed world simply don't understand how challenging it is to live day-to-day without solid and reliable infrastructure, or how effective Starlink has been in improving that. Very few other projects have been THIS successful at THIS scale. I think more people should be aware of the good that it does.
It has been a disruptive technology in so many of the best ways.
https://www.reuters.com/investigations/musk-ordered-shutdown...
> "In situ measurements showed evidence of a 1,000% increase in stratospheric aluminum levels from 1976 to 1984 (Zolensky et al., 1989), which was associated with the emission of hundreds of tons of such particles from solid rocket motors (SRM) during atmospheric ascent (Brady et al., 1994)"
If you follow Brady et al. (1994)[0], you'll read that every Space Shuttle launch (Table 1) deposited 112 tons of Al2O3 into the stratosphere (>15 km).
[0] https://apps.dtic.mil/sti/pdfs/ADA289852.pdf
This isn't a new phenomenon at all; in fact the peak alumina pollution from in the past (112 tons per STS launch) exceeds the worst-case future estimates from academic research (360 tons per year from satellite reentries).
(/meta Coincidentally, I once linked that exact Brady paper on HN, three years ago[1]. Actually, long before the current social media fad for being concerned about satellites. At the time I wrote, and this has truly aged well, "No one ever gave a shit").
The importance of this distinction is acknowledged in Brady et al (1994):
>The exact chemical nature, as well as size distribution (and total surface area) of particles formed in rocket exhaust in the stratosphere is currently unknown. Preliminary experiments at Aerospace by L. R. Martin indicate that plausible particle compositions give highly variable rates of direct ozone destruction.
Nice username btw.
Emphasis on negligible. Assuming 0.07 to 0.28 ppm lead [1] in meteoroids, space is dosing us with half to 2 kg a year [2].
[1] https://www.sciencedirect.com/science/article/abs/pii/001670...
[2] https://earthsky.org/space/tons-of-extraterrestrial-dust-fal...
> The researchers found particles containing the rare elements niobium and hafnium. They also found a significant number of particles contained copper, lithium and aluminum at concentrations far exceeding the abundance found in space dust.