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Elon Musk Explains Why He's Building 'Starship' Out of Stainless Steel (popularmechanics.com)
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."
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.
"Are you hungry? I haven't eaten since later this afternoon." -- Primer
He follows the UK standard practice of using Fahrenheit for high temperatures and Celsius for lows.
How can I believe you when you tell me what I don't want to hear?
How do you short SpaceX? They're not even public.
It's actually going to be a time machine, not a spaceship. Musk: "If my calculations are correct, when this baby hits .88 C... you're gonna see some serious shit."
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.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
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...
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?
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)
-1K - you divided by 0.
If the universe is someone's simulation -- does that mean the stars are just stuck pixels?
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.
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.
Slashdot still doesnâ(TM)t support Unicode after it was added to the HTML standard in 1997.
I think you're confusing the companies. Tesla is not SpaceX. Nor vice versa.
Seven puppies were harmed during the making of this post.
You miss hey!'s point.... NONE of these fuckers started seriously caring about making electric cars until Tesla came on the scene. Them most of them banded together against him to try to legislate him out of business. Then finally when Tesla actually started selling cars and it turned out they were pretty decent, got the shit scared out of them and started looking into making their own cars. Even if Tesla is a total failure, Must has brought about the age of the electric car.
Seven puppies were harmed during the making of this post.
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.