Elon Musk Explains Why He's Building 'Starship' Out of Stainless Steel (popularmechanics.com) 308
Long-time Slashdot reader darkwing_bmf writes: In an exclusive interview with Popular Mechanics, SpaceX founder Elon Musk explains why stainless steel is the best material to build rocket ships, beating carbon fiber in cost, durability and even weight.
"As far as we know, this marks the first time the material has been used in spacecraft construction since some early, ill-fated attempts during the Atlas program in the late 1950s," reports Popular Mechanics.
"It took me quite a bit of effort to convince the team to go in this direction..." Musk tells them. But among the other benefits "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... But steel, you can do 1500, 1600 degrees Fahrenheit."
"As far as we know, this marks the first time the material has been used in spacecraft construction since some early, ill-fated attempts during the Atlas program in the late 1950s," reports Popular Mechanics.
"It took me quite a bit of effort to convince the team to go in this direction..." Musk tells them. But among the other benefits "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... But steel, you can do 1500, 1600 degrees Fahrenheit."
takes big toke off of spliff (Score:3, Funny)
funding secured, my man. Now pass the Doritos
Re:takes big toke off of spliff (Score:5, Insightful)
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Shit! I read that as snort more!
--
EM.
Fahrenheit? (Score:2, Insightful)
Musk not using SI units?
Maybe the shorts were right.
Re:Fahrenheit? (Score:5, Funny)
He follows the UK standard practice of using Fahrenheit for high temperatures and Celsius for lows.
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That's not the UK standard.
The UK standard is some newspapers use Fahrenheit for everything, everyone else uses Celsius and maybe puts the Imperial measurement in brackets later.
High temperatures tend to be Celsius only, along with a comparison to some other really hot thing like the sun.
Or did I just hear a whoosh because you were joking? I can't tell.
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The Islamabad Daily Herald (incorporating "What Burka?") is not a UK newspaper.
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I was going to say the Daily Mail too, thanks for the example.
Re:Fahrenheit? (Score:5, Informative)
How do you short SpaceX? They're not even public.
Re:Fahrenheit? (Score:5, Informative)
Except that it's a privately held company, which means there aren't any shares on the market for you to buy / sell, and even if you could get one of the (restricted number of) private investors to play along, you wouldn't be able to get anyone else to play because there are certain windows of time when share sales / purchase are allowed. And a maximum amount of investors allowed.
This is why companies have IPOs and become publicly traded. You don't know what you are talking about.
Short version: you can't short a privately held company.
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Re:Fahrenheit? (Score:4, Informative)
Musk not using SI units?
Maybe the shorts were right.
Maybe he's building another Mars Climate Orbiter [wikipedia.org] ...
On September 23, 1999, communication with the spacecraft was lost as the spacecraft went into orbital insertion, due to ground-based computer software which produced output in non-SI units of pound-force seconds (lbfs) instead of the SI units of newton-seconds (Ns) specified in the contract between NASA and Lockheed. The spacecraft encountered Mars on a trajectory that brought it too close to the planet, and it was either destroyed in the atmosphere or re-entered heliocentric space after leaving Mars' atmosphere.
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American company using imperial units?
Re:Try it yourself (Score:5, Informative)
The funny part is that the quote is incorrect - either he said Celsius and the article misquotes him or he said something wrong. The melting point of stainless steel is roughly 1500-1600 C (well somewhere in the range from 1325 - 1530)!
E.g. see: https://www.bssa.org.uk/topics... [bssa.org.uk]
I think whether you want temperature in C or Fahrenheit is a matter of taste. I grew up with C and think it is easy enough -
0C - melting point for ice - if it is below roughly 0 it might be icy and you should be carefull
17C or so is ok to swim in
21-23C nice indoor temp.
30C a bit too hot.
100C water boils.
What more is necessary to know?
Re:Try it yourself (Score:5, Funny)
What more is necessary to know?
I like K. It's better than C or F because it appears later in the alphabet. And you don't have to bother with those silly negative numbers -- HOW can you have a negative temperature?
0K - a bit too cold.
300K - reasonable
3000K - a bit too hot.
6000K - a bit too hot AND bright. (Link) [space.com]
-1K - you divided by 0.
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Of course, if it's below 0K outside, you'd probably want to just stay in
https://en.wikipedia.org/wiki/... [wikipedia.org]
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HOW can you have a negative temperature?
You've obviously never been outside in Canada at night (any time after 3pm) in February. When you feel your balls actually entering your abdominal cavity and sheltering somewhere between your kidneys and your liver, you have reached negative temperature.
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What more is necessary to know?
Steel glows cherry red around 1400-1500 F [wikipedia.org], at which point work hardening is removed. Aluminum melts at around 1250 F. Those are both pretty important to me....
Melting point is unimportant (Score:3)
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C is just a terrible unit of measurement for expressing temperature.
You're right. K is where it's at baby. Until someone points out to you that the size of 1K is exactly the same as the size of 1 C....the only difference being where the scale sets the zero point.
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I'm in full support of metric units elsewhere, but that doesn't look, nor sound, nearly so exciting... C is just a terrible unit of measurement for expressing temperature. Even more true of weather ranges.
Maybe if you're a dullard...
Says the guy backing the system that's based off of the number of fingers humans have. Converting between cm, meters, km is done by moving a decimal point. Converting between inches, feet, yards and miles isn't some simple shit you can do on your fingers. Plus you have to know how many inches are in a foot, how many feet in a yard and how many yards are in a mile. And none of those are some base 10 crap you can do on your fingers. Hell, it's not even the same from one unit to the next. 12 inches to a foot,
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What the fuck does horse racing measurements have to do with anything but horse racing?
Nobody in aerospace engineering gives a shit about furlongs or short heads, and never has.
That's like saying that anyone in aerospace engineering is measuring things in (american) football field lengths, or sides of a baseball diamond. It's completely irrelevant.
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Where the hell does the .001 come from?
It's 220 yards, and a yard is 3 feet. int x int = int.
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Love the changes (Score:5, Interesting)
I was frequently Debbie Downer about using CF for BFR. It's not a resilient material, and organics don't play well with LOX, nor does CF like operating at cryogenic temperatures; you're fighting against its innate material properties. I love the use of stainless. It's so much more forgiving, and people who know how to work with it are a dime a dozen. Just everything about this design will be so much easier. And cheaper. And faster. And safer.
I wouldn't be surprised if they outright build Starship and Super Heavy outside, shipyard-style. It wouldn't exactly be the first time giant pressuretight steel vessels designed for dealing with harsh conditions were built outside in salt-air conditions (e.g., almost every refinery on Earth). Corrosion rates in marine environments are on the order of decades to centuries per millimeter, depending on the stainless alloy (unlike alumium which is sensitive to salt) - and galvanic corrosion due to junctions with dissimilar metals (such as alumium) tend to corrode the other metal, not the steel (again, unlike alumium). There should be no issues with an under-construction rocket shell sitting outside for months until they can get it enclosed for more sensitive work on the interior. The LOX tank would need to be well cleaned, mind you, since LOX doesn't play well with contaminants (CH4 isn't particularly sensitive), and as always, welds need to be properly inspected.
It's an unconventional choice, but one which I've been really glad to see.
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That said, I hope they don't bother making a replacement fairing for the hopper. It completed the hopper aesthetically, but there's no real need for it for small-scale testing. Just launch the tanks. The rate of progress on them has been crazy-fast.
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I love the use of stainless. It's so much more forgiving, and people who know how to work with it are a dime a dozen.
Not to mention, the effect on the flux dispersal. [youtube.com]
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I'm not going to post two dozen links; use Teh Google. But if you want, say, a reference that I've always opposed building BFR out of carbon fibre? Here you go [slashdot.org].
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I often waver between using the US spelling and the British spelling... so a while back I decided to split the difference and use Davy's original spelling ;) It's a perfectly cromulent spelling.
It's actually going to be a time machine.. (Score:5, Funny)
Perfect reason (Score:2)
: "If my calculations are correct, when this baby hits .88 C.
Someone above was asking why Musk didn't use C instead of F to refer to the temperature the hull can take...
You just demonstrated why - when talking about spaceships you only want to use F for temperatures so you don't confuse it with the use of C for speed. :-)
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Only GP would use C when he meant to write c.
I can't believe a programmer (as all Slashdot posters are) is really going to pretend that the fidelity of case will always be maintained across a lot of documents! Remember these are eventually getting into the hands of, or being created by, engineers.
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measured relative to the speed of light, c (not C)
Yeah I prefer not to risk potential confusion to the whims of a bad font or someone who TYPES IN ALL CAPS.
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Ridiculous comment (Score:2, Troll)
They built something like 500 balloon-tank Atlas missiles at Atlas II and they were extremely successful, every single one of them was stainless steel. They launched the last one in the early 2000's , and the Atlas II has a perfect success record. Hardly "ill-fated attempts one the Atlas program in the late 50's".
Musk, of course, is not using the stainless in an ideal manner, mostly for show. That's because he is more PT Barnum than Werner Von Braun.
Dr. Zarkov was right (Score:2)
Curious choice for the "energy efficient" team (Score:2)
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While 304 isn't the strongest grade (IIRC) I just don't see the case for stainless. It's not like rockets need long term rust resistance, and you have to sacrifice various desirable properties for that. Why not a high grade of non stainless?
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I think the original interview answered that questions. Normal steels become brittle at cryogenic temperatures whereas stainless steel actually becomes stronger at those temperatures
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Something else must be doing bad things to existing materials that design work discovered when "really" out in space.
Think of neutrons on earth in a nuclear reactor.
Stainless steel has its place in such a harsh environment around nuclear energy production.
Will space be a harsh to a lot of existing materials?
Tested and well understood stainless steel is the way to ensure things keep working when actually going into real outer space?
Re:Curious choice for the "energy efficient" team (Score:5, Informative)
You are only looking at the room-temperature performance, while the advantages of stainless are under cryogenic and reentry conditions. An aluminum structure (or their originally planned carbon fiber composite) would need to be protected by TPS materials that are either extremely fragile, or thick and relatively heavy (and still rather fragile).
Also look at the problems NASA has had welding the thick aluminum walls of the SLS tank. Steels, even stainless steels, are easier to work with, and their density means the tank walls can be thinner. SpaceX uses the same materials and processes on their aluminum Falcon 9 rocket, and is quite familiar with their advantages and limitations.
Video explains most: (Score:2)
Everyday Astronaut [youtu.be]
The important question: will it show fingerprints? (Score:3)
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You know that some of his revolutionary ideas really worked out? Like landing rockets. Also his electric cars were far ahead of the competition for a while, although you could just attribute this to putting a large amount of money in it at the right time. Well, that's what he is really good at.
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The reason you have never heard of it is because you Musk zealots only "know" about things that Musk does. You aren't interested in science, or technology. You just worship the P.T. Barnum of the tech world.
From what I can tell, Blue Origin had the first flight, but SpaceX had the first useful flight. Kind of like how GM had the first modern EV, and Toyota made the first one that normal people wanted to buy but only produced it in small numbers, but Tesla made the first one many people wanted to buy (and actually sold it.) I'd compare Elon Musk to Steve Jobs, except he'd probably be smart enough to get cancer treated if he had it.
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Educate yourself faggot.
I educated myself with WP before posting. Naturally, I'm not going to watch your video. Do you actually find people who do what you say? Sad fucks, if you do, but not as sad as you.
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Re: Going by Mr. Musk's other fancy projects.... (Score:2)
Well that's the first time I hear it was done forty years ago.
It wasn't. The guy you're talking to is just an asshole who is heavily invested in shorting Tesla, so will regularly tell all kinds of lies about anything Elon touches.
If you scroll up on the page you can watch him claim that the Linux kernel was more revolutionary than anything SpaceX has done. And as insane as that it, it's not even the most ridiculous thing he's ever said!
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The reason it hasn't been done since is because it is a dubious idea.
If only Mr. Watt had realized that sticking a bunch of water into a barrel and sealing it then lighting a fire on it was a dubious idea because everyone knew it would blow up and take half the building with it....
He made it work. And not you or anyone else will EVER be able to take the credit for that away from him.
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Takeoff, hover and landing was done forty years ago.
Exactly. He's saying that all Musk and SpaceX have achieved is basically, well, Grasshopper.
...complete success is predicted. (Score:2)
Going by Mr. Musk's other fancy projects like the Hyperloop and his tunnels or even the flame thrower, the outlook for a stainless steel rocket is... ...fantastic.
The hyper loop already has a demo tunnel built when many said NOTHING would ever be built. It completely validates the concept, to the point you can be sure to see commercial implementation.
The flame thrower turned out really well, to the point I was very sad I didn't get to order one before they were gone.
And of course, Tesla is practically the
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The hyperloop WAS NOT HIS CONCEPT.
I can see you slipped up here, since obviously you meant to respond to the original poster who claimed the lack of Hyperloop showed that Mush was a failure. Thanks for helping my argument by noting you cannot even attribute the Hyperloop idea to Musk.
Your support is noted and appreciated!
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It already does something (Score:2)
A demo tunnel, that can't do jack else
I dare you to drive a mile in LA at rush hour in under 4 minutes.
Musk can.
And as the tunnel obviously works and was built as easily as he claimed, at the low cost he claimed, there will be many more to come.
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You do seem a bit confused, Confused.
Hyperloop isn't a project, it is an idea that was proposed in general terms.
The BBQ "flame thrower" was a huge success.
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And if they work, liek the tunnels, they end up being about the same as those made by others.
Musk's tunnel cost $10m for a 1.4 miles. For comparison my city just built a #)!@ bike lane for $12m/mile. They could have built an exclusive right-of-way bike tunnel for less with Boring Company.
By the way I assume this is what you're reffering to for "about the same"
For a better comparison Super Excavators (the previous owners of Godot) used the exact same machine to build a 1,640 ft sewer overflow tunnel for $12.4 million, or scaling up $38 million/mile
Hardly "about the same" and this was their very first attempt which was more about fact-finding than a finished product. Not to mention the competitor using the same boring machine is using it for sewers. Even at $40m a mile vs $10m or
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You know there are many varieties of stainless steel? Some are extremely tough proprietary alloys like Inconel or Monel. This isn't your cheap 316 kitchen sink steel.
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Most of the time, Mr. Musk's cunning plans overlook some aspect and in the end they either fall very short on the original expectation or don't work at all.
What? Name one major project which has failed. What actually happens is that they are all late, but that's very different from the never that you claim. And you know what they say about late and never.
And if they work, liek the tunnels, they end up being about the same as those made by others.
The tunnels are just tunnels. They're not meant to be different from other tunnels, they're meant to be cheaper and faster. They already are (slightly) and the next borer will be much better.
In engineering there are very few overlooked secrets to revolutionise things like Mr. Musk always twitters. Fortunately most engineers aren't the fumbling dolts he thinks they are.
Absolutely nothing Musk has done has been a new idea. All of it has just been him deciding to bankroll things which nobo
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Solar City did pretty poorly, but only because it required that Americans pay their bills on time.
Yes, it certainly has done so far. But it's not dead, just on standby. It can be spun off again if that makes sense.
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because no other rocket has successfully used stainless steel? you might want to check up on that before the space/missile buffs make mincemint out of you
Re:Going by Mr. Musk's other fancy projects.... (Score:5, Insightful)
How on earth do you discount the success of Tesla and SpaceX? Musk is obviously far more than just a byproduct of PayPal.
Musk may not be the smartest guy in the room but he has a very solid track record of saying his companies are going to do something people consider outside the envelope, and not just making it work but making it work really well.
It sure seems like with the success that SpaceX has had, anyone discounting what Musk has to say about how rockets should be built and operated, is very probably either a jerk or an idiot. In either case they are even more probably wrong.
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Have you looked at car prices lately? Ford somehow made people think pickup trucks are worth $60k and they can't build enough of them. The 0.01% are not buying Teslas.
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His argument is based on global income figures, because clearly Tesla (and every other car manufacturer) is directing their marketing at poor people in war-torn countries that barely can feed themselves. But somehow that matters for Tesla, and not Jaguar Land Rover, Volkswagen AG, Daimler, etc.; you know - all the other car manufacturers that sell similarly priced vehicles to the exact same markets, and have all announced EVs meant to directly compete with Tesla.
Oh, but Tesla makes "niche" cars that the re
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Tesla makes cars for the rich, sure. But it has also revolutionized the industry by creating the first production electric car that wasn't a glorified golf cart.
As for launching satellites to LEO, most *nations* can't do that yet.
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Tesla makes cars for the rich, sure. But it has also revolutionized the industry by creating the first production electric car that wasn't a glorified golf cart.
You forgot the Toyota RAV4 EV. Not much range, but otherwise highly credible, and owners adore them.
What Tesla has done is made the first EV that the masses want to buy, and then actually gone on to sell them to a lot of people. Most RAV4 EVs were leased, all GM EV-1s were leased... But this is not a trivial achievement, especially given that Tesla is a brand new automaker.
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Nope. Like the GM EV1, the 1st Gen RAV4 EV was lease only. The second gen RAV4 EV was designed in conjunction with, wait for it.... Tesla.
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Nope. Like the GM EV1, the 1st Gen RAV4 EV was lease only.
Nope. It was lease only at the beginning, but "at the lessees' request, many units were sold after the vehicle was discontinued. [wikipedia.org]" and also "A total of 328 RAV4 EVs were sold directly to consumers throughout 2002 and into 2003. [thetruthaboutcars.com]"
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After which they halted production, even though they had customers who wanted to buy.
The point is not to take anything away from Toyota or GM, but what they built in the 90s weren't intended to become production vehicles; they were more like large-run prototypes used to obtain real-world data on EVs. These vehicles were historically significant, but they didn't shake up the market and force other manufacturers to get into EVs.
That's partly a matter of timing. It couldn't be done prior to 2000; ten years i
Re:Going by Mr. Musk's other fancy projects.... (Score:5, Insightful)
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"Stuff that impresses you isn't groundbreaking. You know what is groundbreaking? Stuff that impresses ME!"
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Re:Going by Mr. Musk's other fancy projects.... (Score:4, Insightful)
Because engineers never over-think anything, or immediately discount ideas because of past failures.
Sometimes "why not? I want a real answer" is a very useful exercise for an engineering team, as it requires challenging assumptions.
If this team discounted stainless steel from the beginning in favor of other materials because reasons, and then was made to actually enumerate those reasons and found them lacking, then good work was done.
As always, the proof is in the testing. If the rocket spectacularly fails due to the stainless steel construction, then I guess your idiot trolling will be justified. But if it works, then you're just an idiot troll.
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Google Inconel.
Re:Stainless "seems" like a bad idea (Score:5, Informative)
I'm not sure about yours, but my washing machine doesn't have to operate at cryogenic through incandescent temperatures. Stainless steel alloys can be *really* good at cryogenic temperatures where common steel and carbon fiber composites are brittle. Ordinary steel would rapidly burn if exposed to reentry conditions, aluminum would melt and carbon fiber would start to decompose and burn if not covered with a substantial thermal protection layer.
Aluminum and carbon fiber have their own problems with manufacturability, durability, and ease of modification or repairs. Stainless alloys let them sidestep those difficulties while getting many of the advantages of ordinary steels.
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You don’t occasionally put your clothes through a liquid ammonia rinse? It gets rid of any pathogens quite effectively
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Carbon fiber/epoxy would be a terrible choice for the tankage for exactly the reason you suggest - it would just shatter like glass from shock at cyrogenic temperatures and you couldn't insulate it well enough. Stainless, use conventionally, is a very good choice from all aspects, and as the Atlas experience showed, it can make for a very high performance system. The Atlas stage and a half system had one of higher stage mass ratios ever fielded, the entire missile would go into orbit, it's as close to SSTO
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The Atlas was a near-SSTO vehicle that used stainless steel balloon tanks, but that certainly does not mean that stainless steel is only useful for near-SSTO vehicles with balloon tanks. The fact that you can't reach the mass fractions needed for SSTO with rigid stainless steel tanks is rather irrelevant to staged vehicles.
Starship will only ever go to orbit when launched on a booster. As such, it has sufficiently forgiving mass ratios that it doesn't need balloon tanks.
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OMG, you're right! Musk and all his rocket engineers are idiots!
Oh wait, they're going to cool the skin on reentry.
Re: Hot topic (Score:2)
Which is why they plan on using active cooling during reentry. The fact that it's harder to melt just means less need for cooling.
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