Slashdot Mirror
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."
How do you short SpaceX? They're not even public.
Musk not using SI units?
Maybe the shorts were right.
Maybe he's building another Mars Climate Orbiter ...
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.
It must have been something you assimilated. . . .
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?
His "tunnel" was literally that: a tunnel. It didn't contain anything that you need to make a real transportation tunnel. That is why it was $10m. More marketing BS from Musk desperately trying to convince governments to fork over more public money.
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.
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.
"Are you hungry? I haven't eaten since later this afternoon." -- Primer
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.
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.