[windsurfer]

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]

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.

[simonh]

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.

[HPsquared]

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).

[cinntaile]

It is simply easier to ban mercury propellants than it is to ban coal plant mercury emissions. A lot more people are dependent on the coal plants so the time and energy it takes to make changes there is just way bigger. Of course work is being done there as well, it just takes way longer.

[simulate-me]

What is your argument exactly? That as long as coal power plants emit airborne mercury, then anyone else can emit mercury as well as long as they emit less? This is just a form of whataboutism. We don't have ready, scalable alternatives to coal power at the moment, or don't have the will / money to bring alternatives into service. We do have alternatives to mercury-based space fuels.

[danuker]

> a different agenda

I'll bite: fossil fuel is running the show?

[_joel]

The megaconstellations use reaction mass wheels and hall effect thrusters (Krypton in Starlink). I'm not sure any use mercury as a fuel.

[onion2k]

You must have missed the "before it becomes common" part of the post you've replied to. No one is suggesting it's being used a lot. The ban is to stop it before it does.