Elon Musk

Originally, yeah, we were going to make Starship out of carbon fiber.

And carbon fiber is pretty expensive.

You know, you can generally, when you do volume production, you can get any given thing to start to approach its material cost.

The problem with carbon fiber is that material cost is still very high.

So it's about 50 times, particularly if you go for a high-strength specialized carbon fiber that can handle cryogenic oxygen, it's like, quote, roughly 50 times the cost of steel.

And at least in theory, it would be lighter.

People generally think of steel as being heavy and carbon fiber as being light.

And for room temperature applications, you know, except more or less room temperature applications like a Formula One car, static aerostructure or any kind of aerostructure really is going to, you're going to probably be better off with carbon fiber.

Now, the problem is that we were trying to make this enormous rocket out of carbon fiber, and our progress was extremely slow.

Yes.

At first glance, most people would think that the choice for making something light would be carbon fiber.

Now, the thing is that when you make something very enormous out of carbon fiber, and then you try to have the carbon fiber be efficiently cured, meaning not room temperature cured, because sometimes you've got like 50 plies of

of carbon fiber.

And carbon fiber is really carbon string and glue.

And in order to have high strength, you need an autoclave.

So something that's essentially a high pressure oven.

And if you have something that's a gigantic, the oven's got to be bigger than the rocket.

So we're trying to make the autoclave that's bigger than any autoclave that's ever existed.

or do room temperature cure, which takes a long time and has issues.

But the final issue is that we're just making very slow progress with carbon fiber.