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Comment by davidguetta | Hacker News Reader

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davidguetta

- salt water is horrific for anything

- time to transport, move back into initial position.

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This is the answer. Salt water destroys the engines.

That makes sense - sending out barges / recovery vehicles into the ocean can't be cheap.

The environmental impact of a chopsticks landing is likely a whole lot less damaging too.

What do you figure is worse for chemical changes to materials, being engulfed in a big call of plasma, or being dunked in the ocean?

I don’t know any chemistry but there seem to be a lot of smart people round here. What say you?

Seagoing ships are good at being in salt water but don't deal as well with being engulfed in plasma. Starship is pretty good at being engulfed in plasma but doesn't handle being engulfed in salt water very well. Making a single ship that can handle both is a very tall order, even just doing one or the other is hard.

Seagoing ships are pretty good at floating on top of salt water for a while, but they're not very good at being "dunked" in it (i.e. sunken). It is possible to raise sunken ships and rehabilitate them to regular service, and this has been before, but it generally destroys everything inside, and requires a ton of work. Salt water is one of the most corrosive substances we know of.

Ocean is worse. (For rockets.)

- used to be an engineer in aerospace

Designing it for both is probably worse than either one separately

Being dunked in seawater while still being red/white hot from the plasma.

Dunked in the ocean. There just isn't a ton of plasma and it's not very good at transferring heat to things it isn't being pressed up against. So heat shields and the like function very well. Seawater by contrast gets everywhere, and if it does even a little damage, keeps doing it for a long time.

A lot of the damage happens as soon as the spacecraft enters the water, because it's extremely hot, causing more chemical reactions than you might think. Even jet engines have trouble with corrosion from ingesting small amounts of aerosolized salt water.[1]

1. https://ntrs.nasa.gov/api/citations/19690007944/downloads/19...

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