4 ms·

Is it really clad in stainless steel? Seems like there would be lighter materials that would serve that role.

davidivadavid 6y ago
There are lighter materials but apparently they're more expensive and harder to work with, so steel ended up winning the cost/benefit analysis. There's been ample discussion about that when they originally started talking about it, e.g. https://www.space.com/43101-elon-musk-explains-stainless-steel-starship.html https://www.space.com/43101-elon-musk-explains-stainless-ste...
- bombcar 6y ago
  I think the real reason is Elon Musk wants Buck Rogers style spaceships and will do whatever necessary to get there.
  - bigbubba 6y ago
    Probably not, SpaceX invested a lot of time and effort into composite tanks before giving that up.
  - bryanlarsen 6y ago
    Having product that appeals to his not-so-hidden inner thirteen year old boy is definitely a motivation for Elon Musk. Exhibit A: cybertruck. Actually getting to Mars is a higher priority, though.
    - nerpderp82 6y ago
      Exhibit A', flame thrower.
gliptic 6y ago
It's not clad in stainless steel -- it _is_ stainless steel. The reason being it's cheap, and that especially the alloy they use is very robust under cryogenic temperatures as well as high temperatures.
- pixl97 6y ago
  Yep, you can watch videos of the assembly on YouTube by Boca Chica Girl and see all the components. Stainless through and through.
Obi_Juan_Kenobi 6y ago
That's the problem with 'seems like'
emilecantin 6y ago
At room temperature, yes. At the range of temperatures this needs to operate at, stainless is actually lighter for the required strength. Keep in mind that this is a tank for cryogenic propellants (almost-solid liquid oxygen and methane), that needs to survive atmospheric re-entry from interplanetary speeds, so it needs to be strong in temperatures around -200°C to +400°C.
crispyambulance 6y ago
I realize there's technical reasons/tradeoff's for using stainless, but goddamn it looks cool. It will be even more magnificent if they can make the skin taut. Isn't that the intent in future models? Though the sheet metal waviness is nice in a retro way too.
ohazi 6y ago
It needs to act as both a tank wall for cryogenic liquids that won't crack and as a backing for a heat shield that won't melt. Tough trade-off. Melting point of aluminum is too low. Burning point of epoxy/carbon fiber is also probably quite low, but it's also famously hard to work with and get reliably good results that you can actually inspect. Titanium might work, but is also had to work with and tends to crack.

There are lighter materials but apparently they're more expensive and harder to work with, so steel ended up winning the cost/benefit analysis. There's been ample discussion about that when they originally started talking about it, e.g. https://www.space.com/43101-elon-musk-explains-stainless-steel-starship.html https://www.space.com/43101-elon-musk-explains-stainless-ste...

bombcar 6y ago
I think the real reason is Elon Musk wants Buck Rogers style spaceships and will do whatever necessary to get there.
- bigbubba 6y ago
  Probably not, SpaceX invested a lot of time and effort into composite tanks before giving that up.
- bryanlarsen 6y ago
  Having product that appeals to his not-so-hidden inner thirteen year old boy is definitely a motivation for Elon Musk. Exhibit A: cybertruck. Actually getting to Mars is a higher priority, though.
  - nerpderp82 6y ago
    Exhibit A', flame thrower.

gliptic 6y ago

It's not clad in stainless steel -- it _is_ stainless steel. The reason being it's cheap, and that especially the alloy they use is very robust under cryogenic temperatures as well as high temperatures.

pixl97 6y ago
Yep, you can watch videos of the assembly on YouTube by Boca Chica Girl and see all the components. Stainless through and through.

Obi_Juan_Kenobi 6y ago

That's the problem with 'seems like'

emilecantin 6y ago

At room temperature, yes. At the range of temperatures this needs to operate at, stainless is actually lighter for the required strength. Keep in mind that this is a tank for cryogenic propellants (almost-solid liquid oxygen and methane), that needs to survive atmospheric re-entry from interplanetary speeds, so it needs to be strong in temperatures around -200°C to +400°C.

crispyambulance 6y ago

I realize there's technical reasons/tradeoff's for using stainless, but goddamn it looks cool. It will be even more magnificent if they can make the skin taut. Isn't that the intent in future models? Though the sheet metal waviness is nice in a retro way too.

ohazi 6y ago

It needs to act as both a tank wall for cryogenic liquids that won't crack and as a backing for a heat shield that won't melt. Tough trade-off. Melting point of aluminum is too low. Burning point of epoxy/carbon fiber is also probably quite low, but it's also famously hard to work with and get reliably good results that you can actually inspect. Titanium might work, but is also had to work with and tends to crack.