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A comment on SpaceX Crew Dragon Splashes Down After Historic Test Flight. Parent comment

Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by rsj_hn on Friday March 08, 2019 @06:26PM (#19343257)
That's interesting. I always assumed that most of the damage happened on re-entry and not the splashdown. Can you elaborate on why the splashdown kills re-use?
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by huehehue on Friday March 08, 2019 @06:43PM (#19343340)
"Although water retrieval has been attempted, it is not recommended due to the adverse effect that salt water has on avionics, electronics, and structures. This approach was abandoned due to the elevated cost associated with refurbishing salt water damaged components. By avoiding water retrieval, the engines would avoid maintenance that would have resulted from the corrosive nature of the salt water and thereby expedite turnaround time. When considering recovery of reusable systems, salt water is much more severe than returning to land at the launch site."

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by based2 on Friday March 08, 2019 @07:33PM (#19343613)
just create a movable water pool for the ocean.

http://news.mit.edu/2015/shockwave-process-desalination-wate...

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by varjag on Friday March 08, 2019 @07:15PM (#19343520)
This is related to rocket engines, not ballistic descent capsules.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by Teever on Friday March 08, 2019 @08:56PM (#19343982)
Ballistic descent capsules such as the Dragon have rocket engines in them.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by avmich on Saturday March 09, 2019 @11:28AM (#19346858)
True. However some capsules have rather small engines, and small available delta-v, so the whole propulsion package can be made, say, replaceable. Soyuz, for example, lands using only about 30 kilograms of hydrogen peroxide to help with control during reentry. Maybe Crew Dragon can evolve to have this subsystem serviceable.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by bahmboo on Friday March 08, 2019 @06:53PM (#19343390)
I live by salt water. Salt water destroys everything. Sometimes quickly but always eventually. Ok, maybe not fish.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by lenocinor on Friday March 08, 2019 @07:11PM (#19343500)
It's really true. In your home it'll even happen to your indoor stuff if you're not careful.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by varjag on Friday March 08, 2019 @07:16PM (#19343530)
Carbon steel hull ships traverse saltwater for many decades however.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by spricket on Friday March 08, 2019 @08:28PM (#19343886)
They use cathodic protection which makes the underwater hull basically immune to corrosion. But this doesn't stop water that gets on top or inside.

Ships rust like hell. I've known some guys in the Navy and they said it was common for everything unarmored to have holes all over.

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by emiliobumachar on Friday March 08, 2019 @07:49PM (#19343725)
What's their maintenance like?
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by varjag on Friday March 08, 2019 @07:57PM (#19343756)
Scrub/repaint every few years?

In comparison, splashdown capsules spend maybe few hours tops in the water.

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by lutorm on Friday March 08, 2019 @08:24PM (#19343863)
The problem is that, unlike ships, they're generally not designed to be water proof. It's not the exterior that's the problem.
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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by luke0016 on Friday March 08, 2019 @09:48PM (#19344140)
I mean, the crew part of it is water proof, right? It has to be air tight...

I'm guessing there are things on the "outside" that might still have issues?

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by rblatz on Saturday March 09, 2019 @01:07AM (#19344759)
The first part of your post reminded me of this quote from Futurama.

Professor Farnsworth: Good Lord! That's over 5000 atmospheres of pressure!

Fry: How many atmospheres can the ship withstand?

Professor Farnsworth: Well, it was built for space travel, so anywhere between zero and one.

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by politician on Friday March 08, 2019 @09:54PM (#19344157)
> ... there are things on the "outside" that might still have issues ...

... on the second reentry attempt.

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Re:SpaceX Crew Dragon Splashes Down After Historic Test Flight by deedubaya on Friday March 08, 2019 @06:31PM (#19343279)
I'm guessing its the salt water that is the problem.
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