Author Topic: BFR/ITS risk due to composites  (Read 24115 times)

Online envy887

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Re: BFR/ITS risk due to composites
« Reply #80 on: 02/21/2018 03:21 AM »
nickel-iron-lead isn't light weight.  How thick a layer do they need?  Does it flake off?  Or wear away?  How much mass is that for large tanks?
Once again: An Invar liner is the last resort. Elon said that they look for a coating that can be sprayed on.

I wonder if the coating would be spray foam insulation, BFS needs insulation for deep space and Mars surface (to avoid freezing out dry ice). But urethane foam seems like it would be just as bad as carbon epoxy in the face of hot GOX. A silica fiber based insulation sounds like a better bet but I don't know if they could spray it.

There are high temperature phenolic CRFP resins that can take up to 500 C for short times. Not just stronger at elevated temperatures, but also more resistant to oxidation.

Offline Patchouli

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Re: BFR/ITS risk due to composites
« Reply #81 on: 02/21/2018 04:49 AM »
Another solution could the inner most layers of the tanks be made from something like Nonburnite which can handle -260C to +280C.
This should exceed anything they'll see in service by a good margin.

https://omnexus.specialchem.com/tech-library/article/nonburning-high-heat-composite-material-of-the-future
« Last Edit: 02/21/2018 04:50 AM by Patchouli »

Offline john smith 19

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Re: BFR/ITS risk due to composites
« Reply #82 on: 02/21/2018 06:38 AM »
Another solution could the inner most layers of the tanks be made from something like Nonburnite which can handle -260C to +280C.
This should exceed anything they'll see in service by a good margin.

https://omnexus.specialchem.com/tech-library/article/nonburning-high-heat-composite-material-of-the-future
Unfortunately XCOR is now defunct.

Does anyone know what happened to the nonburnite IP?

I wonder if the coating would be spray foam insulation, BFS needs insulation for deep space and Mars surface (to avoid freezing out dry ice). But urethane foam seems like it would be just as bad as carbon epoxy in the face of hot GOX. A silica fiber based insulation sounds like a better bet but I don't know if they could spray it.
Such materials do exist and are in use for refurbishing furnaces. I've no idea how fragile or heavy they are.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Online jpo234

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Re: BFR/ITS risk due to composites
« Reply #83 on: 02/21/2018 06:57 AM »
Another solution could the inner most layers of the tanks be made from something like Nonburnite which can handle -260C to +280C.
This should exceed anything they'll see in service by a good margin.

https://omnexus.specialchem.com/tech-library/article/nonburning-high-heat-composite-material-of-the-future

This sounds (from my layman perspective) exactly like the kind of material Elon was talking about.
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Online envy887

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Re: BFR/ITS risk due to composites
« Reply #84 on: 02/21/2018 01:46 PM »
Another solution could the inner most layers of the tanks be made from something like Nonburnite which can handle -260C to +280C.
This should exceed anything they'll see in service by a good margin.

https://omnexus.specialchem.com/tech-library/article/nonburning-high-heat-composite-material-of-the-future
Unfortunately XCOR is now defunct.

Does anyone know what happened to the nonburnite IP?

I wonder if the coating would be spray foam insulation, BFS needs insulation for deep space and Mars surface (to avoid freezing out dry ice). But urethane foam seems like it would be just as bad as carbon epoxy in the face of hot GOX. A silica fiber based insulation sounds like a better bet but I don't know if they could spray it.
Such materials do exist and are in use for refurbishing furnaces. I've no idea how fragile or heavy they are.

Not heavy at all, but lightweight silica materials rather brittle. Aerogel and the Shuttle tiles are two examples.

Offline john smith 19

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Re: BFR/ITS risk due to composites
« Reply #85 on: 02/21/2018 09:01 PM »
Not heavy at all, but lightweight silica materials rather brittle. Aerogel and the Shuttle tiles are two examples.
Not necessarily an issue, provided its thermal expansion coefficient matches (or can be made to match) that of the CFRP material (so no cracking due to temperature cycling stresses) and its dense enough (or has a dense skin) to keep the GO2 away from the CFRP.

The issue with all surface treatments or protective coatings (from TPS to TBC's on turbine blades to LOX tank linings) is a)How do you monitor their integrity b)If the integrity of the layer fails how does the design cope with this (or is this one of those "Must never ever happen" events?) c) How do you refurbish if it is damaged.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

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