Starlink generated pollution

[meekGee]

The basic numbers don't hold up even on first scrutiny, and in this case I'm glad they got debunked quickly and clearly.

Please provide said numbers that don't hold up to scrutiny.

How do you even start to compare 1000 tons per year, most of which is battery and structure and solar panels, and is largely vaporized in the upper atmosphere and over oceans, to the impact of global industrial pollution?  It's orders of magnitude off....

And how come nobody thought of this before SpaceX?  Starlink may equal all of the other satellites combined, but that's still ballpark the same thing....

Which is what ESA found out:

Based on the record, we are not convinced that reentering SpaceX Gen2 Starlink satellites may have a significant environmental impact necessitating an EA. As SpaceX states, the European Space Agency (ESA) initiated two studies, looking into specifically the atmospheric impact of spacecraft demise upon reentry and concluding that the impact was negligible compared to other anthropogenic activities.

I think the burden is on whoever initiated or is propagating these concerns to actually show a number.

What material is of concern? How much do they think is being dumped?  How does it compare to other sources?

If they don't, then what they're doing is just starting a rumor and demanding that the target of the rumor prove that it's wrong.  It's called FUD.

[Robotbeat]

The basic numbers don't hold up even on first scrutiny, and in this case I'm glad they got debunked quickly and clearly.

Please provide said numbers that don't hold up to scrutiny.

The "numbers" (it's not even numbers, just assertions) that claim this is a significant environmental problem. (FCC/SpaceX show they aren't by referencing a European study, see up-thread: https://forum.nasaspaceflight.com/index.php?topic=55599.msg2444437#msg2444437.)

As far as EVs, just about any modern study that isn't essentially funded by fossil fuel interests (or traditional automakers) shows that even with presumably increased manufacturing emissions, the per-mile of emissions of EVs in a place like the US is less than half of conventional cars (less than a third if you don't count manufacturing emissions).
https://www.epa.gov/greenvehicles/electric-vehicle-myths#Myth2

[TheRadicalModerate]

How do you even start to compare 1000 tons per year, most of which is battery and structure and solar panels, and is largely vaporized in the upper atmosphere and over oceans, to the impact of global industrial pollution?  It's orders of magnitude off....

This has nothing to do with terrestrial pollution.  It has to do with ozone depleting substances.  Alumina is a catalyst that's good at cleaving chlorine ions off of chlorine reservoir compounds, mostly chlorine nitrates and hydrochloric acid.  Chlorine ions are themselves a catalyst for destroying ozone, with one chlorine ion cycling over and over between Cl^- and ClO^- forms.  Wikipedia says one Cl atom is good for converting 100,000 ozone molecules to O₂, before it's bonded back into one of the reservoir compounds.

And how come nobody thought of this before SpaceX?  Starlink may equal all of the other satellites combined, but that's still ballpark the same thing....

The non-paranoid, non-conspiracy-theory explanation is simply that nobody imagined constellations of 30,000 satellites in orbits that could decay in 5 years.  When they could imagine them, they started thinking about the implications.

Which is what ESA found out:

Based on the record, we are not convinced that reentering SpaceX Gen2 Starlink satellites may have a significant environmental impact necessitating an EA. As SpaceX states, the European Space Agency (ESA) initiated two studies, looking into specifically the atmospheric impact of spacecraft demise upon reentry and concluding that the impact was negligible compared to other anthropogenic activities.

I think the burden is on whoever initiated or is propagating these concerns to actually show a number.

On this, we agree.  There is no consensus, let alone proof, that this is actually a problem, which is exactly why the regulators left it alone.  They were right to do so.

But that's not the same as denying the existence of a problem.  The gap between those two states is an indication that research is required.

If they don't, then what they're doing is just starting a rumor and demanding that the target of the rumor prove that it's wrong.  It's called FUD.

They certainly aren't demanding that SpaceX and other megaconstellation operators prove them wrong.  Seems to me that they'd like for people to think about the problem.

I have no idea if the authors of the paper have a political axe to grind--and neither do you.  But that doesn't really matter if the problem they've surfaced has a substantial enough analysis behind it to warrant additional research.

I'm far from an expert on atmospheric chemistry, but I can do order-of-magnitude estimates as well as the next person, and to me it looks like the amount of alumina injected into the stratosphere by a Starlink-scale constellation is a substantial chunk of the natural injection of the same compound via meteors and cosmic dust.  I encourage you to do your own estimates, instead of just waving your arms around.

Seems to me that you're advocating for a specific scientific investigation not to be done, simply because you don't like the implications.  I don't like the implications either, but I'm still willing to let the scientific method take its course.  You should be, too.

[Robotbeat]

There’s a point where we can start talking about recovering the hardware or upgrading it in situ instead of just burning it up. But we’re not near that point. To imply otherwise right now, without hard data, just vague concerns without numbers and ignoring FCC/ESA studies, is concern-trolling. Bring actual data so concerns can be examined in a falsifiable way.

Shuttle launched up to 9 times per year, burning 1000 tons of aluminum-heavy SRB propellant each time. That’s much greater mass than the Starlink satellites per year that have been approved.

[steveleach]

There’s a point where we can start talking about recovering the hardware or upgrading it in situ instead of just burning it up. But we’re not near that point. To imply otherwise right now, without hard data, just vague concerns without numbers and ignoring FCC/ESA studies, is concern-trolling. Bring actual data so concerns can be examined in a falsifiable way.

Shuttle launched up to 9 times per year, burning 1000 tons of aluminum-heavy SRB propellant each time. That’s much greater mass than the Starlink satellites per year that have been approved.

The fact that someone else is/was polluting more than you doesn't absolve you from responsibility. And as a species we've made enough mistakes that we should know by now to stop these things before they become a problem.

I can't speak for TheRadicalModerate, but my own concerns here are generic, rather than specific to Starlink, in case anyone thinks this is me hating on SpaceX. Anyone who launches something into orbit should, imho, should be required to assess the impact of it being in orbit, and the impact of it burning up in the atmosphere (if that is what will happen to it at the end of its life).

To me it sounds like SpaceX have already done that, at least to the FCC's satisfaction, with Starlink.

And let's dispense with the "concern trolling" allegations please.

[Robotbeat]

Yes. The question has already been answered by the FCC, and additional concerns brought up should be quantitative, not vague.

[DanClemmensen]

The fact that someone else is/was polluting more than you doesn't absolve you from responsibility. And as a species we've made enough mistakes that we should know by now to stop these things before they become a problem.

I can't speak for TheRadicalModerate, but my own concerns here are generic, rather than specific to Starlink, in case anyone thinks this is me hating on SpaceX. Anyone who launches something into orbit should, imho, should be required to assess the impact of it being in orbit, and the impact of it burning up in the atmosphere (if that is what will happen to it at the end of its life).

A big problem with generic environmental reviews is they assume that the status quo is acceptable. This ignores any potential benefit the project has for the environment. For example, a satellite constellation might reduce the need to install fiber, and the total environmental cost of the fiber network install may be high.

The extreme example of this is ignoring climate change when delaying the use of nuclear power generation, starting in about 1970. Yes, almost every environmental and safety objection to nuclear power is valid, but climate change is likely to be far worse. Today, renewables are a better choice, but we now have a 50-year accumulation of CO₂ to deal with.

[Barley]

Shuttle launched up to 9 times per year, burning 1000 tons of aluminum-heavy SRB propellant each time. That’s much greater mass than the Starlink satellites per year that have been approved.

Addressing just a narrow issue.

Does it matter how high the alumina is released?  I'd guess that lower down it rains out quickly and you'd have to inject it higher in the stratosphere to have much effect on the ozone layer.   Eyeballing the booster thrust curves over half the burn is before max-Q at 11km and more than 3/4 below 16km, perhaps much more that 3/4 it's not a well calibrated eyeball.

In contrast everything injected from above will eventually reach the ozone layer.

[TheRadicalModerate]

I can't speak for TheRadicalModerate, but my own concerns here are generic, rather than specific to Starlink, in case anyone thinks this is me hating on SpaceX. Anyone who launches something into orbit should, imho, should be required to assess the impact of it being in orbit, and the impact of it burning up in the atmosphere (if that is what will happen to it at the end of its life).

To me it sounds like SpaceX have already done that, at least to the FCC's satisfaction, with Starlink.

My concern is specific to what the scientific community is hypothesizing, i.e., that certain types of rocket debris and exhaust are ozone-depleting substances.  At this point, that hypothesis is yet to be disproved, and there is some evidence that it may be correct.  Apparently, neither the FCC nor ESA thinks that there's enough evidence to take regulatory action at this time.  That sounds like a correct assessment.

Note that the amount of time from when Rowland and Molina came up with the CFC hypothesis, which was immediately dismissed as crackpottery, both by large swathes of the scientific in general and by the CFC manufacturers in great detail, to when the Montreal Protocol was ratified, was about 13 years.  That's the blink of an eye in diplomatic terms.  So I'd expect that if any experimental evidence comes to light  that shows a steep ozone depletion curve, either as a result of alumina reentry debris or from SRBs spewing out not only alumina but also a wide variety of chlorinated chemicals and nitrous oxide, international action will be swift.

Again, there's little evidence to back up the debris hypothesis at this time, and regulation is unlikely until evidence exists--if it ever does.  But this bears watching.

[TheRadicalModerate]

Shuttle launched up to 9 times per year, burning 1000 tons of aluminum-heavy SRB propellant each time. That’s much greater mass than the Starlink satellites per year that have been approved.

Addressing just a narrow issue.

Does it matter how high the alumina is released?  I'd guess that lower down it rains out quickly and you'd have to inject it higher in the stratosphere to have much effect on the ozone layer.   Eyeballing the booster thrust curves over half the burn is before max-Q at 11km and more than 3/4 below 16km, perhaps much more that 3/4 it's not a well calibrated eyeball.

In contrast everything injected from above will eventually reach the ozone layer.

Alumina particles from SRBs are pretty big, which does help them precipitate out fairly quickly.  Alumina from meteoroids and dust are extremely small, which makes them more effective aerosols, with high surface/volume ratios.  But I don't think we have a huge amount of data about the distribution of particle sizes that come from an orbital reentry.

My guess is that the lower speed of entry (as opposed to interplanetary entry speeds for meteoroids) implies bigger droplets of alumina, which would reduce the area/volume ratio and also precipitate out quicker.  So there are lots of unknowns that need to be carefully characterized before anybody gets their knickers in a twist about this.

[Robotbeat]

Still waiting for these concern arguments to either link to studies or provide falsifiable, quantifiable (ie number-containing) statements.

…rather than handwaving and rhetoric.

[TheRadicalModerate]

Still waiting for these concern arguments to either link to studies or provide falsifiable, quantifiable (ie number-containing) statements.

…rather than handwaving and rhetoric.

The paper that's been reported on in SpaceNews and other outlets is behind a paywall, but here's the link if you want to spend $32 on it.

In addition I linked a PhD dissertation on alumina catalysts up-thread.  This paper is oriented more around making Space Shuttle ozone depletion models more accurate, and comes to the conclusion that the alumina is a significant activator of ODSes, and needs to be included in the modeling--as does what little I can read of the Shutler paper.

The only numbers I'm fooling with are the ones comparing aluminum entering the atmosphere from orbital debris with the natural rate of aluminum from meteoroids/cosmic dust, and noting that, if Starlink really winds up with 30,000 birds, then the reentry aluminum mass is likely at least as large as the natural mass.  Contrary to what you're insinuating here, those numbers are up-thread.

My position is that this doesn't require regulation right now, and may never require regulation, but that we ought to be really sure that we haven't created yet another significant ozone depletion pathway.  If you'd like to characterize that as concern-trolling, go right ahead.

[Robotbeat]

Thanks, that’s exactly what I wanted.

[meekGee]

Still waiting for these concern arguments to either link to studies or provide falsifiable, quantifiable (ie number-containing) statements.

…rather than handwaving and rhetoric.

The paper that's been reported on in SpaceNews and other outlets is behind a paywall, but here's the link if you want to spend $32 on it.

In addition I linked a PhD dissertation on alumina catalysts up-thread.  This paper is oriented more around making Space Shuttle ozone depletion models more accurate, and comes to the conclusion that the alumina is a significant activator of ODSes, and needs to be included in the modeling--as does what little I can read of the Shutler paper.

The only numbers I'm fooling with are the ones comparing aluminum entering the atmosphere from orbital debris with the natural rate of aluminum from meteoroids/cosmic dust, and noting that, if Starlink really winds up with 30,000 birds, then the reentry aluminum mass is likely at least as large as the natural mass.  Contrary to what you're insinuating here, those numbers are up-thread.

My position is that this doesn't require regulation right now, and may never require regulation, but that we ought to be really sure that we haven't created yet another significant ozone depletion pathway.  If you'd like to characterize that as concern-trolling, go right ahead.

Yup interestingly 30,000 satellite, 3 year life span, and 2 tons per satellite, you arrive at about 50 tons/day which is the same as the estimated meteor mass input.  Coincidence?  I smell a rat.  Clearly Musk wants to replace meteors.

However, my "orders of magnitude" comment was about industry and volcanoes (millions or billions of tons) compared with the aforementioned 20,000 tons.  Sure they're emitted at lower altitudes, but so were CFCs and we know how that went.

And I'd mention the Space Shuttle not because it created more pollution, but because the same characters that propagate the "Starlink Pollution" meme were not concerned one bit about Shuttle pollution.  Just like "Electric cars use Coal" and "immensely complex and high risk", you sometimes just need to look where the memes are coming from.

[TheRadicalModerate]

Still waiting for these concern arguments to either link to studies or provide falsifiable, quantifiable (ie number-containing) statements.

…rather than handwaving and rhetoric.

The paper that's been reported on in SpaceNews and other outlets is behind a paywall, but here's the link if you want to spend $32 on it.

In addition I linked a PhD dissertation on alumina catalysts up-thread.  This paper is oriented more around making Space Shuttle ozone depletion models more accurate, and comes to the conclusion that the alumina is a significant activator of ODSes, and needs to be included in the modeling--as does what little I can read of the Shutler paper.

The only numbers I'm fooling with are the ones comparing aluminum entering the atmosphere from orbital debris with the natural rate of aluminum from meteoroids/cosmic dust, and noting that, if Starlink really winds up with 30,000 birds, then the reentry aluminum mass is likely at least as large as the natural mass.  Contrary to what you're insinuating here, those numbers are up-thread.

My position is that this doesn't require regulation right now, and may never require regulation, but that we ought to be really sure that we haven't created yet another significant ozone depletion pathway.  If you'd like to characterize that as concern-trolling, go right ahead.

Yup interestingly 30,000 satellite, 3 year life span, and 2 tons per satellite, you arrive at about 50 tons/day which is the same as the estimated meteor mass input.  Coincidence?  I smell a rat.  Clearly Musk wants to replace meteors.

30,000 birds, 5 year lifetime.  33t/day.  Pick some percentage that you think will be aluminum.  25%?  1500t/year.

The Spencer dissertation used 1.6E4t of meteoroid dust, and didn't distinguish between silicates, Fe, Ni, Al, Mg, and Ti oxides.¹  That would make the new stuff a 9.4% increase.  If you do an apples-to-apples comparison with just Al, which is, according to another reference, 1.4% of the meteoroid mass,  the Starlink aluminum would be 670% more.

However, my "orders of magnitude" comment was about industry and volcanoes (millions or billions of tons) compared with the aforementioned 20,000 tons.  Sure they're emitted at lower altitudes, but so were CFCs and we know how that went.

So your argument is that, because we emitted lots of CFCs and then took action to drastically reduce their emission, that we shouldn't worry about adding new sources that can enhance the conversion of chlorine from its reservoirs?

And yes, there are natural sources of ozone depleting substances.  But those natural sources are why the ozone layer has roughly the concentration that it has.  The question is whether we're going to add substances that force it away from that equilibrium.

And I'd mention the Space Shuttle not because it created more pollution, but because the same characters that propagate the "Starlink Pollution" meme were not concerned one bit about Shuttle pollution.  Just like "Electric cars use Coal" and "immensely complex and high risk", you sometimes just need to look where the memes are coming from.

The "same characters" did a fair amount of work looking a Space Shuttle SRBs and concluded that the effect was significant but nothing like the effects of CFCs.  I suspect that this will be the ultimate answer to the orbital debris question.  But at this point, we don't know. 

Are your suspicions that some secret cabal of scientists is out to get us so great that you'd actively suppress their work?  And if you're not that paranoid, then isn't this just a perfectly legitimate piece of atmospheric science that you can expect to turn out to be nothing?

__________________
¹Spencer also asserts that there are other substrates beside alumina that can catalyze free chlorine production, which I assume is his rationale for comparing things to all meteoroid dust, not just the aluminum in the dust.  However, he only measured the reactivity of alumina and silicate glasses.

[Robotbeat]

I honestly don’t think the exact metal oxide chosen necessarily makes a huge difference. All would likely have similar catalytic effects (or not).

[TheRadicalModerate]

I honestly don’t think the exact metal oxide chosen necessarily makes a huge difference. All would likely have similar catalytic effects (or not).

If I'm reading the dissertation right, the issue is that HCl adsorbs quite readily to certain substrates but not others, and the presence of HCl, when bound to the substrates, allowed chlorine to cleave off of chlorine nitrates.  They tested alumina, sliica-based glasses, and then used teflon and sulfuric acid droplets as controls.  Alumina and glass had roughly the same reactivity, so it's not a terrible assumption that other oxide-based substrates might as well.  But this vastly exceeds my meager chemistry knowledge.

A 9% reactivity increase would obviously be much more benign than a 670% increase.  If this becomes a hot topic, I'd expect that there are plenty of grad students who can characterize this much more precisely.

Remember, small changes in free chlorine concentrations cause large changes in ozone depletion.  Knowing that number is fairly important.

[Robotbeat]

Just saying that if you're comparing meteorites to Starlink and you cherrypick alumina for no particular reason except that it artificially amplifies the comparison by an order of magnitude… …that is not exactly a neutral decision.

[TheRadicalModerate]

Just saying that if you're comparing meteorites to Starlink and you cherrypick alumina for no particular reason except that it artificially amplifies the comparison by an order of magnitude… …that is not exactly a neutral decision.

I'm cherrypicking alumina because that's what the research is cherrypicking.  Now, there's a reason for that:  a lot of the research was into SRB pollution.  I'd expect similar measurements for all of the other likely metallic oxides to be coming soon.  If it turns out that the same chemistry occurs with most metallic oxides, then it's likely a non-problem.  But if not, then we need to keep an eye on this.

[Robotbeat]

Except the most likely result is the effects of metal oxides are similar. The opposite assumption, that other metal oxides have negligible effect, is exceedingly unlikely, and yet that’s the one you implicitly chose… yeah, this is cherrypicking.