There is not one specific reason for SpaceX moving to stainless instead of carbon fiber (which was the original plan).
And generally speaking, it seems they made the right choice so far.
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And generally speaking, it seems they made the right choice so far.
if the launch failed is it really the right choice?
historically most rockets use aerospace grade aluminum specifically for weight:strength ratio. stainless steel does not have the same weight:strength ratio.
Who the hell cares about weight control when you have that much power. The Starship's takeoff looked like a mini nuclear bomb going off...
well, it has 3.4 kT of fossil fuel on it.
thrust:weight ratio is important for any spaceship but if they didn't care, and only cared about cost, why stainless? Just use carbon steel which is far cheaper, has higher tensile strength and easier to machine/weld, and stop corrosion with paint.
Stainless steel is resistant to embrittlement from cryogenic fuel. This is why they use stainless to make LNG fuel tanks for example. Regular carbon steel would crack and fracture with exposure to cryogenics. This is why for example the original Atlas rocket also used stainless propellant tanks.
SpaceX could not get composites to work. Heck, they could not even get the composite fuel tanks to work in a standard water pressure burst test. Let alone with cryogenic propellant. They could not get the composites to be default free to a point to work after years and much money wasted in testing. That is why they went back to metals. Just think about it, you are talking about carbon fibers glued together, then baked. Good luck making something like that defect free at that kind of size.
I am fairly sure they could use aluminium lithium, like they use in Falcon 9, on the first stage of the Starship, but for whatever reason they did not do this.
SpaceX could not get composites to work. Heck, they could not even get the composite fuel tanks to work in a standard water pressure burst test. Let alone with cryogenic propellant. They could not get the composites to be default free to a point to work after years and much money wasted in testing. That is why they went back to metals. Just think about it, you are talking about carbon fibers glued together, then baked. Good luck making something like that defect free at that kind of size.
I am fairly sure they could use aluminium lithium, like they use in Falcon 9, on the first stage of the Starship, but for whatever reason they did not do this.
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not for fuel tanks but for the external structure, which is insulated from the tanks.
The main reason for that was cost I think. The steel is just much cheaper. And the rocket is huge.
If you make composite metal structures of steel and aluminium you are also taking chances. Ever heard of galvanic corrosion? It has been a major bugbear in the US LCS program. Because they decided to mate aluminum and steel together.
If you make composite metal structures of steel and aluminium you are also taking chances. Ever heard of galvanic corrosion? It has been a major bugbear in the US LCS program. Because they decided to mate aluminum and steel together.
Galvanic corrosion matters for LCS because it is in salt water 24/7 and both steel and aluminum components are in contact with the water. salt water is one of the most corrosive media and even corrodes stainless. But galvanic corrosion doesn't apply if they're not wetted parts.
Cost is not only the material cost but the labor cost to form it.
Stainless is much harder to work than aluminum, costing 3x more by CNC machining.
IMO the so far best footage of the Space X Starship explosion
ispace - japanese lunar lander company - has been planning to land on the moon in a couple days:
JUICE was launched:
Japan delayed the launch of the H2A after the H3 failure:
South Korea is adding another 19.5% to its space budget YOY:
Boeing's Starliner has been delayed ... again. Can they delay the delays now?
JUICE was launched:
Japan delayed the launch of the H2A after the H3 failure:
South Korea is adding another 19.5% to its space budget YOY:
Boeing's Starliner has been delayed ... again. Can they delay the delays now?