Sunday, October 23, 2022

Mercury thrusters

All that extra mercury we got around the place, that we can't sell? How about using it as a propellant!!

Fine: it's cheap. Lewin Day claims it's free - some companies will even pay to get that sh!t away from them. It's liquid at Earth-equatorial/tropical surface temperatures where you'll do most launches. The molecules are massive so the energy in that Rocket Equation delivers more thrust along with the exhaust-velocity (Isp). And the propellant-tank will just be shorter. Won't need to be pressurised either. This removes mass from the cargo.

I'm unsure what they were hoping to use for that tank; liquid metals anneal with other metals. Maybe they hose Teflon around the insides first.

They were proposing mercury for stationkeeping and orbital-adjustments over Earth. We're, like... using this planet (pdf). Also if one sat-company is allowed it they'll all want it. As Day summarises the pdf: 2,000 satellites with 100 kg of propellant on board would deposit 20,000 kg of mercury into the upper atmosphere each year for a decade. Once up there it literally snows out into the clouds. But the sunsets will be lit.

Yeah that's... not good.

I do however wonder about shipping mercury past Earth... That's for the next post.

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