from the they-might-need-a-duvet-with-all-theose-sheets dept.
Nikkei Asian Review reports that SpaceX is establishing a business relationship with Japanese material manufacturer Toray Industries. They're supposedly working on a $1.99 billion to $2.98 billion USD deal in which Toray will supply SpaceX with sheets of carbon fiber.
The two sides are aiming to finalize the agreement this fall after hammering out prices, time frames and other terms.
[...]
The likely plan is to supply carbon fiber sheets from a Toray production center in Alabama, with SpaceX to further process the material into end products. Adding dedicated production lines at a South Carolina plant will be considered if SpaceX's demand for carbon fiber grows as expected.
In Ars Technica's regurgitation of this story, one delicious chunk of information is brought to the surface (albeit coated in the putrid vile of a misused "irony"):
In a bit of irony, Toray is likely to produce carbon fibers for SpaceX at its Decatur, Alabama-based factory, which is located in the same city where SpaceX competitor United Launch Alliance manufactures its rockets.
One angle the Nekkei Asian Review article touches on is that per-rocket cost should matter less now that SpaceX is successfully landing rockets.
SpaceX aims to hold down expenses by re-using rockets and spacecraft. Originally, the company made rockets mostly out of aluminum to keep costs low, using carbon fiber only for a few parts, such as connecting joints.
Another angle mentioned is SpaceX's ambitions for Mars.
SpaceX is switching to carbon fibers from aluminum as it develops heavy rockets for carrying people and large quantities of material. A lighter body would allow more cargo to be loaded, which would cut transport costs.
The Falcon Heavy rocket, currently under development, would carry more than three times the payload that the Falcon 9, the current model in service, is capable of handling. The rocket is slated for a test launch as early as the end of the year. SpaceX will start launching satellites next year and carry out a joint unmanned mission to Mars with NASA in May 2018.
Do Soylentils think that this move towards carbon fiber has more to do with reusable rocket advances, or the requirements of Mars missions? Are those issues even separable? What other angles should we be discussing?
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Popular Mechanics has interviewed SpaceX CEO Elon Musk about his decision to move to a stainless steel design for Starship Super Heavy (formerly BFR). The interview reveals new details about the design, including micro-perforations on the outside of the windward side of the rocket that can bleed water or fuel for cooling:
Ryan D'Agostino: How does stainless steel compare [to carbon fiber]?
Elon Musk: The thing that's counterintuitive about the stainless steel is, it's obviously cheap, it's obviously fast—but it's not obviously the lightest. But it is actually the lightest. If you look at the properties of a high-quality stainless steel, the thing that isn't obvious is that at cryogenic temperatures, the strength is boosted by 50 percent.
Most steels, as you get to cryogenic temperatures, they become very brittle. You've seen the trick with liquid nitrogen on typical carbon steel: You spray liquid nitrogen, you can hit it with a hammer, it shatters like glass. That's true of most steels, but not of stainless steel that has a high chrome-nickel content. That actually increases in strength, and ductility is still very high. So you have, like, 12 to 18 percent ductility at, say, minus 330 degrees Fahrenheit. Very ductile, very tough. No fracture issues.
[...] [Here's] the other benefit of steel: It has a high melting point. Much higher than aluminum, and although carbon fiber doesn't melt, the resin gets destroyed at a certain temperature. So typically aluminum or carbon fiber, for a steady-state operating temperature, you're really limited to about 300 degrees Fahrenheit. It's not that high. You can take little brief excursions above that, maybe 350. Four hundred, you're really pushing it. It weakens. And there are some carbon fibers that can take 400 degrees Fahrenheit, but then you have strength knockdowns. But steel, you can do 1500, 1600 degrees Fahrenheit.
(Score: -1, Redundant) by Anonymous Coward on Wednesday August 17 2016, @06:07AM
Oh god oh god I'm so horny I can't stop to think about whether musky will wash off his rocket before he reuses it.
(Score: 0) by Anonymous Coward on Wednesday August 17 2016, @06:21AM
Those rockets look pretty charred after landing. Is carbon fiber (usually embedded in plastic or epoxy) up to that kind of heat?
(Score: 3, Informative) by mhajicek on Wednesday August 17 2016, @06:38AM
Depends mostly on the resin.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 0) by Anonymous Coward on Wednesday August 17 2016, @08:45AM
SpaceX to build rockets out of space-age materials.
(Score: 0) by Anonymous Coward on Wednesday August 17 2016, @12:44PM
> coated in the putrid vile of a misused "irony"
Somebody has anger issues.
(Score: 3, Interesting) by VLM on Wednesday August 17 2016, @12:45PM
There's enough variation in basic material properties such that rockets won't get made out of just CF, Al-Li, or traditional alloys (or even good ole steel).
Its like a balanced D+D RPG, theres just some things each are good at or bad at.
Fatigue life is a black art under any circumstance but fatigue life of CF is a black art of black arts. You can't really weld or repair CF, once it breaks or wears you have to pretty much toss the whole part out.
SpaceX already uses Al-Li alloys in at least some tanks. Its a gross generalization but more or less true that nobody is ever going to build a CF cryogenic oxidizer tank for multiple reasons but everyone including the legacy space shuttle is using or used Al-Li cryogenic O2 tanks. And if you make the tank a structural component you're building a partially Al-Li rocket, that's just how it is.
For heat nothing handles high temps like a nice sheet of niobium. And yes the falcon 9 engine nozzles are made of niobium alloy.
(Score: 2) by carguy on Wednesday August 17 2016, @01:20PM
Along with the materials VLM nentions, there are also "carbon-carbon" materials that are good for high temperatures -- for example some race car brake disks and clutch disks.
(Score: 2) by Grishnakh on Wednesday August 17 2016, @04:29PM
For heat nothing handles high temps like a nice sheet of niobium. And yes the falcon 9 engine nozzles are made of niobium alloy.
I thought beryllium was the standard material for this kind of thing.
(Score: 3, Informative) by VLM on Wednesday August 17 2016, @05:36PM
Well, it has great stiffness so you could size a nozzle for vacuum expansion and fire it at sea level somewhat cheaper than most other things without it buckling or at least being less likely. Maybe stiffness would help with acoustic resonance too. Or maybe make it worse?
You got two strategies for stopping maneuvering thrusters from melting down, run that sucker hot, niobium style, and rely on radiative cooling, or run that sucker cold and rely on essentially a monster heat sink to keep the thing cool. Be is pretty good metal for storing heat, very high specific heat capacity. So you can run your thruster twice as long with Be before it melts than with Al or steel (made up number, but its a pretty large factor like maybe two or so...)
Be corrodes terrible, especially chlorides, so one landing on the sea barge and they'd have to scrap it unless they went to crazy effort. Also the oxide coating is only stable up to red hot or so. That's the problem with using it as a nozzle, if you overheat it in the atmosphere it'll burn like magnesium. Oh and the smoke/oxide from the burned Be causes cancer or whatever it kills you real good unlike MgO. Still in space it would probably make a decent nozzle.
It would make a good beam or arm to mount a maneuvering thruster upon because of its stiffness.
If you can be certain your fuel combustion products are neutral to reducing I bet it would be an OK nozzle material, at least used in space not sea level, especially not used by the sea. Maybe a nice low temperature low Isp propellent nozzle... I bet something like a geosynch satellite station keeping thruster would be a good application for a Be nozzle.
(Score: 3, Funny) by DeathMonkey on Wednesday August 17 2016, @05:21PM
Damn, that's not even Alanis Morisette level irony! In a bit of irony I place my nachos on the table in front of me where my hands can reach them...
(Score: 2) by Capt. Obvious on Wednesday August 17 2016, @06:21PM
This is a direct consequence of reusable rockets, and only reusable rockets. CF was too expensive for non-reusable rockets, but becomes cost effective when reused because of lower weight... which either means less fuel or heavier payloads.
Whether this was a prerequisite for a Mars mission is irrelevant to the switch - it just means that the switch was a necessary precondition.
(Score: 0) by Anonymous Coward on Wednesday August 17 2016, @08:39PM
Like the article states thou, it may not actually be that simple as it is near impossible to repair. I don't expect them to use it for the whole damn rocket.
(Score: 2) by Capt. Obvious on Wednesday August 17 2016, @09:07PM
I didn't see that in either article. I believe it'll be hard to repair. But, I have no idea how hard it is to repair an aluminum rocket. I mean, if it's part replacement, I'd imagine the aluminum panels are replaced, instead of breaking out that suction cup that removes dings..
CF also is a lot stronger than aluminum. 787 bodies are made out of CF, and they don't worry about huge repair bills.