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How much Mercury does satellite propellant contribute to global airborne mercury, compared to coal fired power plant emissions? My first thought is that this is

by jmpman 5y ago

How much Mercury does satellite propellant contribute to global airborne mercury, compared to coal fired power plant emissions? My first thought is that this is about 7 orders of magnitude less, and thus a ridiculous thing for these technocrats to focus on… but I’m happy to be educated. Or is there some other concern about mercury in satellite propellant?

haukem 5y ago
Coal plants are emitting a lot of unhealthy stuff. The coal plant Jänschwalde in Germany emitted 672kg mercury, 1780kg lead and 208 kg arsenic in 2017 according to the European Pollutant Release and Transfer Register. https://de.wikipedia.org/wiki/Kraftwerk_J%C3%A4nschwalde#Emission https://de.wikipedia.org/wiki/Kraftwerk_J%C3%A4nschwalde#Emi... This is the worst coal plant in Germany, but the others are not so much better.
rsynnott 5y ago
The US emits 52 tonnes/year into the air, apparently. The article claims _hundreds_ of tonnes for one constellation. Which does seem concerning if correct.
- daniel-cussen 5y ago
  Sounds pretty low actually, I'm sure it's much much more. 52 tons is more in line with the amount of gold in that coal. And hundreds of tons for one constellation? How do they get it up there in the first place?
  - rsynnott 5y ago
    These are big constellations of LEO satellites. Starlink, for instance, has 1500 satellites today, with a goal of 30,000. If we assume 10kg of propellant per satellite, then that's 300 tonnes for the finished constellation (Starlink satellites use a noble gas, I believe, but anyone using mercury for a similar scheme would hit that). The whole _world_'s atmospheric emissions only seem to be about 250 tonnes per year.
    - daniel-cussen 5y ago
      I'm not sure. Wankawilca, the world's great mercury mine, and the most valuable mine in the world for centuries, produced mercury on a similar scale as America produced silver. They produced so much silver! I'm reading California had 45,000 tons of mercury not recovered, used in placer mining from 1848 til today. Yeah, no, it's as common as silver in the earth's crust, and it still gets used for artisanal gold mining, the only figure that's not way off is the amount the spaceships use. There's a lot of historical falsifications in mining, because mining produces silver and gold, which is money, and generally people lie about how much money they have, telling a different lie to every person. So Atahualpa's gold, there's no idea how much it was, and further they don't talk about how hard it was to get people not to constantly steal from that room, like what? You think a Spanish soldier is going to just stare at 100 times his weight in gold and be like, I can't wait til King Charles gets his share so I can have mine. You think those guys didn't take bribes for themselves, like OK we'll say you gave all your gold to the gold room, but you get to hang on to this much, and I get this much, nobody's the wiser. It must have been 1000 years of gold production of the Andes. That was el Dorado, they found it right away. And sources tell totally different amounts, some say 200 tons, which is stupid, well do you think they followed GAAP accounting standards when they were eyeballing the gold? How could they measure it? The whole thing was an extortion operation! Obviously the Spanish Conquistadors couldn't let the future know they were torturing the king...publicly? Yeah publicly. And tons of others too. And mining is always like that, it frequently involves slavery too, in complex ways. Because those metals are money, so it's controversial, and private. GM can say how many cars are on the road, but gold mines? Good luck! And I recently dealt with a gold mine someone I know invested in that failed despite excellent deposits because they said the miners were stealing from them--of course, the owners were stealing too. Coming full circle, that's why mercury was so important to Spain, because controlling mercury was the only good way they had of taxing silver and gold mining. But I must also admit my ignorance presently, I don't know how to find sources that I would find satisfying.
      - rsynnott 5y ago
        To be clear, the world's annual production of mercury is far more than 250t/year; it's just that most of it doesn't end up in the atmosphere. The mercury that _does_ end up in the atmosphere is largely incidental, mostly due to coal burning.
londons_explore 5y ago
The way to prevent such 'unevenness' in rules intended to help the environment is to make them taxes and caps on emissions, rather than bans. If for example the US were to decide we need to halve mercury emissions every 5 years for the next 50 years (a 99.9% reduction), then we would implement a system where anyone emitting mercury needed to purchase the 'right' to pollute by auction. Each year the available quota would be reduced. The end result is the levels of pollutants are reduced in the most economically viable way.
jmpman 5y ago
“The potential release of mercury into the upper atmosphere by the firing of mercury-fueled thrusters could almost double the total atmospheric mercury emissions the U.S. is currently responsible for“ Thanks for HN educating me. This would become a significant source of modern US environmental mercury contamination. However, if you summed up all the coal fired power plant mercury emissions over time, this still seems insignificant. It’s not clear how long the mercury cycle takes for mercury to get locked into ocean sediment (effectively out of the food web). If it’s on the order of thousands of years, then satellite propellants are unlikely to be major contributors. But the scale is surprising, and I would congratulate the FCC for pushing this restriction.
ars 5y ago
The article claims "one proposed communications network using the technology could result in hundreds of metric tons of additional mercury" And searching for mercury released by coal burning comes up with 50 tons in the US, and around 250 tons/year worldwide from all sources. I have a hard time believing that figure for the satellite, but if true, it's actually significant. Edit: Seems like an ion engine uses around 1 ton of propellant. So, yah, I guess banning mercury for this, really is significant.
- jccooper 5y ago
  Maybe mercury is different (though I doubt it), but current electric propulsion sats use nothing like that much mass. A Boeing 702 HP (a big GEO comsat) Xenon propulsion system has a capacity for 266kg of Xenon; uses about 5kg per year for station keeping. Constellation sats are usually smaller; a Starlink sat is about 260kg total. Dunno how much krypton they carry, but probably in the low 10s of kg each.
  - sjburt 5y ago
    I think the concern was that some organizations were considering big low-altitude constellations. Once you go below 400km or so the drag increases quite a bit so the idea would be to use near-constant thrust similar to GOCE or SLATS. And there was at least one vendor (Apollo Fusion) proposing a mercury thruster, although I think they have backed off on that. It would have had about 3x the impulse per volume and 2x the impulse per mass of xenon. I think banning it now is wise, if any small operators had started using it it would have been hard to block it for a megaconstellation and it was very clear that anything release in VLEO would be coming back into the atmosphere. Right now there are no users so you aren't really penalizing anyone.
    - deleted 5y ago
      [deleted]
  - rsynnott 5y ago
    It mentions communications _networks_. If you have 10,000 satellites with 10kg propellant each, there's your hundred tonnes of propellant.
windsurfer 5y ago
With the satellite megaconstellations being launched it seems important to ban it before it becomes common. Mercury-based fuels are cheaper than alternatives. Coal as being burned for electricity has an industry standard of scrubbing 90% of mercury emissions, but is moving towards 99% using newer technologies.
- dotancohen 5y ago
  So, it will be four orders of magnitude more for coal than for mega constellations. Seven minus one order of magnitude for better scrubbing and two orders of magnitude for the size of the constellations. Still a ridiculous thing to focus on. If they would focus on reducing atmospheric mercury and direct their efforts against all offenders, I would completely agree. But singling out satellites or deliberately ignoring coal hints that they have a different agenda, and "atmospheric mercury" is their parallel construction.
  - danuker 5y ago
    > a different agenda I'll bite: fossil fuel is running the show?
    - dotancohen 5y ago
      That would seem an obvious agenda, possibly. If you've ever seen the slander against electric vehicles or Tesla, you'll believe that the fossil fuel companies are promoting an agenda.
  - HPsquared 5y ago
    It's a smaller problem, but also easier to solve. The costs of a few suppliers changing their satellite propellants are orders of magnitude less than ending global coal usage (though both would be nice, of course).
  - simonh 5y ago
    Efforts are being directed against all offenders, that's why coal is moving to 99% scrubbing instead of 90% as mentioned up thread. As a species and civilization I think we can manage 'focusing' on more than one thing at a time. Apart from anything else we should at least be consistent, right? If Mercury can reasonably be avoided in any form of polluting usage, it should be.
duskwuff 5y ago
The concern I'd have is that a launch failure could deposit all of the mercury on board in a small area near the launch site. Even if the amount involved isn't significant on a global scale, it would still be enough to have a dramatic and lasting local effect, e.g. on fisheries under the flight path.

by jmpman 5y ago

haukem 5y ago

Coal plants are emitting a lot of unhealthy stuff. The coal plant Jänschwalde in Germany emitted 672kg mercury, 1780kg lead and 208 kg arsenic in 2017 according to the European Pollutant Release and Transfer Register. https://de.wikipedia.org/wiki/Kraftwerk_J%C3%A4nschwalde#Emission https://de.wikipedia.org/wiki/Kraftwerk_J%C3%A4nschwalde#Emi... This is the worst coal plant in Germany, but the others are not so much better.

rsynnott 5y ago

The US emits 52 tonnes/year into the air, apparently. The article claims _hundreds_ of tonnes for one constellation. Which does seem concerning if correct.

daniel-cussen 5y ago
Sounds pretty low actually, I'm sure it's much much more. 52 tons is more in line with the amount of gold in that coal. And hundreds of tons for one constellation? How do they get it up there in the first place?
- rsynnott 5y ago
  These are big constellations of LEO satellites. Starlink, for instance, has 1500 satellites today, with a goal of 30,000. If we assume 10kg of propellant per satellite, then that's 300 tonnes for the finished constellation (Starlink satellites use a noble gas, I believe, but anyone using mercury for a similar scheme would hit that). The whole _world_'s atmospheric emissions only seem to be about 250 tonnes per year.
  - daniel-cussen 5y ago
    I'm not sure. Wankawilca, the world's great mercury mine, and the most valuable mine in the world for centuries, produced mercury on a similar scale as America produced silver. They produced so much silver! I'm reading California had 45,000 tons of mercury not recovered, used in placer mining from 1848 til today. Yeah, no, it's as common as silver in the earth's crust, and it still gets used for artisanal gold mining, the only figure that's not way off is the amount the spaceships use. There's a lot of historical falsifications in mining, because mining produces silver and gold, which is money, and generally people lie about how much money they have, telling a different lie to every person. So Atahualpa's gold, there's no idea how much it was, and further they don't talk about how hard it was to get people not to constantly steal from that room, like what? You think a Spanish soldier is going to just stare at 100 times his weight in gold and be like, I can't wait til King Charles gets his share so I can have mine. You think those guys didn't take bribes for themselves, like OK we'll say you gave all your gold to the gold room, but you get to hang on to this much, and I get this much, nobody's the wiser. It must have been 1000 years of gold production of the Andes. That was el Dorado, they found it right away. And sources tell totally different amounts, some say 200 tons, which is stupid, well do you think they followed GAAP accounting standards when they were eyeballing the gold? How could they measure it? The whole thing was an extortion operation! Obviously the Spanish Conquistadors couldn't let the future know they were torturing the king...publicly? Yeah publicly. And tons of others too. And mining is always like that, it frequently involves slavery too, in complex ways. Because those metals are money, so it's controversial, and private. GM can say how many cars are on the road, but gold mines? Good luck! And I recently dealt with a gold mine someone I know invested in that failed despite excellent deposits because they said the miners were stealing from them--of course, the owners were stealing too. Coming full circle, that's why mercury was so important to Spain, because controlling mercury was the only good way they had of taxing silver and gold mining. But I must also admit my ignorance presently, I don't know how to find sources that I would find satisfying.
    - rsynnott 5y ago
      To be clear, the world's annual production of mercury is far more than 250t/year; it's just that most of it doesn't end up in the atmosphere. The mercury that _does_ end up in the atmosphere is largely incidental, mostly due to coal burning.

londons_explore 5y ago

The way to prevent such 'unevenness' in rules intended to help the environment is to make them taxes and caps on emissions, rather than bans. If for example the US were to decide we need to halve mercury emissions every 5 years for the next 50 years (a 99.9% reduction), then we would implement a system where anyone emitting mercury needed to purchase the 'right' to pollute by auction. Each year the available quota would be reduced. The end result is the levels of pollutants are reduced in the most economically viable way.

jmpman 5y ago

“The potential release of mercury into the upper atmosphere by the firing of mercury-fueled thrusters could almost double the total atmospheric mercury emissions the U.S. is currently responsible for“ Thanks for HN educating me. This would become a significant source of modern US environmental mercury contamination. However, if you summed up all the coal fired power plant mercury emissions over time, this still seems insignificant. It’s not clear how long the mercury cycle takes for mercury to get locked into ocean sediment (effectively out of the food web). If it’s on the order of thousands of years, then satellite propellants are unlikely to be major contributors. But the scale is surprising, and I would congratulate the FCC for pushing this restriction.

ars 5y ago

The article claims "one proposed communications network using the technology could result in hundreds of metric tons of additional mercury" And searching for mercury released by coal burning comes up with 50 tons in the US, and around 250 tons/year worldwide from all sources. I have a hard time believing that figure for the satellite, but if true, it's actually significant. Edit: Seems like an ion engine uses around 1 ton of propellant. So, yah, I guess banning mercury for this, really is significant.

jccooper 5y ago
Maybe mercury is different (though I doubt it), but current electric propulsion sats use nothing like that much mass. A Boeing 702 HP (a big GEO comsat) Xenon propulsion system has a capacity for 266kg of Xenon; uses about 5kg per year for station keeping. Constellation sats are usually smaller; a Starlink sat is about 260kg total. Dunno how much krypton they carry, but probably in the low 10s of kg each.
- sjburt 5y ago
  I think the concern was that some organizations were considering big low-altitude constellations. Once you go below 400km or so the drag increases quite a bit so the idea would be to use near-constant thrust similar to GOCE or SLATS. And there was at least one vendor (Apollo Fusion) proposing a mercury thruster, although I think they have backed off on that. It would have had about 3x the impulse per volume and 2x the impulse per mass of xenon. I think banning it now is wise, if any small operators had started using it it would have been hard to block it for a megaconstellation and it was very clear that anything release in VLEO would be coming back into the atmosphere. Right now there are no users so you aren't really penalizing anyone.
  - deleted 5y ago
    [deleted]
- rsynnott 5y ago
  It mentions communications _networks_. If you have 10,000 satellites with 10kg propellant each, there's your hundred tonnes of propellant.

windsurfer 5y ago

With the satellite megaconstellations being launched it seems important to ban it before it becomes common. Mercury-based fuels are cheaper than alternatives. Coal as being burned for electricity has an industry standard of scrubbing 90% of mercury emissions, but is moving towards 99% using newer technologies.

dotancohen 5y ago
So, it will be four orders of magnitude more for coal than for mega constellations. Seven minus one order of magnitude for better scrubbing and two orders of magnitude for the size of the constellations. Still a ridiculous thing to focus on. If they would focus on reducing atmospheric mercury and direct their efforts against all offenders, I would completely agree. But singling out satellites or deliberately ignoring coal hints that they have a different agenda, and "atmospheric mercury" is their parallel construction.
- danuker 5y ago
  > a different agenda I'll bite: fossil fuel is running the show?
  - dotancohen 5y ago
    That would seem an obvious agenda, possibly. If you've ever seen the slander against electric vehicles or Tesla, you'll believe that the fossil fuel companies are promoting an agenda.
- HPsquared 5y ago
  It's a smaller problem, but also easier to solve. The costs of a few suppliers changing their satellite propellants are orders of magnitude less than ending global coal usage (though both would be nice, of course).
- simonh 5y ago
  Efforts are being directed against all offenders, that's why coal is moving to 99% scrubbing instead of 90% as mentioned up thread. As a species and civilization I think we can manage 'focusing' on more than one thing at a time. Apart from anything else we should at least be consistent, right? If Mercury can reasonably be avoided in any form of polluting usage, it should be.

duskwuff 5y ago

The concern I'd have is that a launch failure could deposit all of the mercury on board in a small area near the launch site. Even if the amount involved isn't significant on a global scale, it would still be enough to have a dramatic and lasting local effect, e.g. on fisheries under the flight path.