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Starship Flight 7

(www.spacex.com)
649 points chinathrow | 11 comments | 16 Jan 25 21:25 UTC | HN request time: 0.001s | source | bottom
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terramex ◴[16 Jan 25 23:04 UTC] No.42732041[source]▶
Looks like second stage broke up over Caribbean, videos of the debris (as seen from ground):

https://x.com/deankolson87/status/1880026759133032662?t=HdHF...

https://x.com/realcamtem/status/1880026604472266800

https://x.com/adavenport354/status/1880026262254809115

Moment of the breakup:

https://www.instagram.com/reel/DE52_hVSeQz/

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dpifke ◴[17 Jan 25 01:58 UTC] No.42733260[source]▶
Preliminary indication is that we had an oxygen/fuel leak in the cavity above the ship engine firewall that was large enough to build pressure in excess of the vent capacity.

Apart from obviously double-checking for leaks, we will add fire suppression to that volume and probably increase vent area. Nothing so far suggests pushing next launch past next month.

https://x.com/elonmusk/status/1880060983734858130

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raverbashing ◴[17 Jan 25 05:49 UTC] No.42734474[source]▶
I'm not sure there's fire suppression effective enough for this type of leak (especially given rocket constraints)
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1. varjag ◴[17 Jan 25 08:40 UTC] No.42735333[source]▶
If you can displace the oxidizer/air remaining in the volume why not.
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2. littlestymaar ◴[17 Jan 25 13:03 UTC] No.42737092[source]▶
The initial tweet says:

> we had an oxygen/fuel leak

If that's correct, then you can't just remove air. The only option would be to cool things down so it stops burning.

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3. shellfishgene ◴[17 Jan 25 14:22 UTC] No.42737765[source]▶
If it was really an oxygen/fuel mix burning I don't think you can do much of anything to stop that.
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4. littlestymaar ◴[17 Jan 25 14:47 UTC] No.42738033{3}[source]▶
If you cooled the mixture at low enough temperature, you'd stop it from burning (like when you pour water on top of a camp fire), but it's not clear how you're supposed to do that in a spaceship where you can't carry a few tons of water for your sprinklers.
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5. varjag ◴[17 Jan 25 17:01 UTC] No.42740322{4}[source]▶
There are other methods too, e.g. fire inhibitors (like Halon or whatever is allowed now) or shockwave to disrupt fire boundary. But I doubt they are very practical on a spaceship.
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6. ben_w ◴[17 Jan 25 17:07 UTC] No.42740449{4}[source]▶
> If you cooled the mixture at low enough temperature, you'd stop it from burning (like when you pour water on top of a camp fire), but it's not clear how you're supposed to do that in a spaceship where you can't carry a few tons of water for your sprinklers.

Also water would make it hotter, given this is liquid oxygen.

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7. m4rtink ◴[17 Jan 25 17:27 UTC] No.42740776{5}[source]▶
First stage (Super Heavy) is flushing the engine bay with massive ammounts of CO2.
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8. littlestymaar ◴[17 Jan 25 21:25 UTC] No.42743439{5}[source]▶
It's not liquid at the point of ignition, that's the thing: if you mixed liquid oxygen and fuel nothing would happen expect the fuel would freeze. For a fire to take place the temperature must reach the fire point temperature, and if you manage to get your fire below this temperature then the fire stops. I don't know how low this temperature can be when the oxidizer is pure oxygen and maybe it's so low water wouldn't be enough, but then you can imagine using other fluids. The problem being the mass burden it adds to a spacecraft, I'm not it'd make any sense given that such q leak should happen in the first place.
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9. littlestymaar ◴[17 Jan 25 21:29 UTC] No.42743472{6}[source]▶
Unless I'm misunderstanding you, it's not the same thing at all: in the case you're talking about you're shielding against nominal heat, which is not the same thing as contingency planning to extinguish a fire that shouldn't be there in the first place.
10. littlestymaar ◴[17 Jan 25 21:32 UTC] No.42743502{5}[source]▶
Not an expert but I'm not too sure about shockwave in a confined space.

How does Halon works?

11. ben_w ◴[17 Jan 25 22:56 UTC] No.42744122{6}[source]▶
I believe LOX is injected into the engine as a liquid, it gets atomised rather than boiled?

And you can have fires where both fuel and oxidiser are solid: thermite reactions.

"Fire point" seems to be more of a factor for conventional fire concerns, albeit I'm judging a phrase I've not heard before by a stub-sized Wikipedia page: https://en.wikipedia.org/wiki/Fire_point