Musk’s Mars rocket is trading carbon fiber for stainless steel

Elon Musk has a plan to get to Mars, but how he’s going to get there keeps changing. The SpaceX CEO said the company had “radically redesigned” its Raptor engine, casting a new steel alloy to contain the hellish engine temperatures during liftoff, and swapping out carbon-fiber components for ”mirror-finish” stainless steel. Musk said SpaceX is switching to stainless steel components because their performance under extreme heat and stress beats out that of carbon-fiber. While carbon-fiber is better at room temperature, Musk stated the extreme heat and cold of space made steel superior despite the added weight. SpaceX engineers are also finishing a “superalloy foundry” at the company’s Hawthorne, California headquarters for its methane-fueled rocket engine known as the Raptor. The metal components must endure hot gas blasting out of the nozzle at 12,000 psi (the same pressure that exists at the deepest part on the ocean).