| > What about the remaining four orders of magnitude? I've already factored in the 90% -> 99% reduction in my comments. This thread started with a statement that satellite thrusters are at "first thought ... about 7 orders of magnitude less" than coal power plants, but where did that number come from? Others are noting that some proposed constellation would have emitted more mercury than the US, which contradicts that thought: https://news.ycombinator.com/item?id=30841820: > 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. https://news.ycombinator.com/item?id=30840666: > Apollo Constellation Engine designed their propulsion systems for mega constellations to use mercury, which is what got PEER involved in this. Popular Mechanics also reported on their plans. Even if Apollo changed their minds since, that's a pretty significant 'near miss'. > https://ecfsapi.fcc.gov/file/111998371507/11_19_18_FCC_compl... > https://www.popularmechanics.com/space/rockets/a25242578/apo... |