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mfb- t1_j9p2k1z wrote

Reply to comment by kittenTakeover in What will be the environmental impact of de-orbiting 42,000 Starlink satellites every five years? (Explanation in post) by OvidPerl

A really rough estimate: We have ~500,000 km^3 of global precipitation per year (1 meter averaged over the surface). If we put all of the 10,000 tonnes of aluminium into that, ignoring chemistry or what happens afterwards, we get an average of 20 ng/liter. For scale, the US EPA recommends no more than 0.05-0.20 mg/liter or 50,000 to 200,000 ng/liter for drinking water.

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jedadkins t1_j9rqjvz wrote

Yea this really seems like a problem of scale, ~2.5m tonnes of aluminum needed to reach the lower bound is an insane amount. Maybe once we start actually commercializing space it could be an issue but by then we should have a better option then just crashing stuff to get it out of orbit

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killercurvesahead t1_j9qauk6 wrote

At that rate whoever’s selling rocketship tickets and plots of land in their own Mars colony is gonna make bank.

Waitaminnit…

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Imperator-Solis t1_j9r8n08 wrote

You might have misread, at that rate it won't reach limits for 2500 years

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EBtwopoint3 t1_j9s3fam wrote

Not 2500 years, until the rate of satellite re-entry becomes 2500 times higher. That is a per year figure, not one that adds up.

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