A few weeks after the surge, Walter Isaacson explains (in his biography of Elon), Musk turned his attention to Raptor, the engine that would power Starship:
Fueled by supercooled liquid methane and liquid oxygen, it had more than twice the thrust of the Falcon 9’s Merlin engine. This meant that Starship would have more thrust than any other rocket in history.
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Raptor was too complex to be mass-manufactured. It looked like a spaghetti bush. So in August 2021, Musk fired the person in charge of its design and personally took on the title of vice president for propulsion. His goal was to get the cost of each engine to around $200,000, a tenth of what it then cost.
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Musk began with his lecture on collegiality. “I want to be super clear,” he began. “You are not the friend of the engineers. You are the judge. If you’re popular among the engineers, this is bad. If you don’t step on toes, I will fire you. Is that clear?” Hughes stuttered a bit as he assented.
Ever since he flew back from Russia and calculated the costs of building his own rockets, Musk had deployed what he called the “idiot index.” That was the ratio of the total cost of a component to the cost of its raw materials. Something with a high idiot index — say, a component that cost $1,000 when the aluminum that composed it cost only $100 — was likely to have a design that was too complex or a manufacturing process that was too inefficient. As Musk put it, “If the ratio is high, you’re an idiot.”
“What are the best parts in Raptor as judged by the idiot index?” Musk asked.
“I’m not sure,” Hughes responded. “I will find out.” This was not good. Musk’s face hardened, and Shotwell shot me a worried glance.
“You better be fucking sure in the future you know these things off the top of your head,” Musk said. “If you ever come into a meeting and do not know what are the idiot parts, then your resignation will be accepted immediately.” He spoke in a monotone and showed no emotion. “How can you fucking not know what the best and worst parts are?”
“I know the cost chart down to the smallest part,” Hughes said quietly. “I just don’t know the cost of the raw materials of those parts.”
“What are the worst five parts?” Musk demanded. Hughes looked at his computer to see if he could calculate an answer. “NO! Don’t look at your screen,” Musk said.
“Just name one. You should know the problematic parts.”
“There’s the half nozzle jacket,” Hughes offered tentatively.
“I think it costs thirteen thousand dollars.”
“It’s made of a single piece of steel,” Musk said, now quizzing him. “How much does that material cost?”
“I think a few thousand dollars?” replied Hughes.
Musk knew the answer. “No. It’s just steel. It’s about two hundred bucks. You have very badly failed. If you don’t improve, your resignation will be accepted. This meeting is over. Done.”
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“We should ask each of them to see if they can get the cost of their part down by eighty percent,” Musk suggested, “and if they can’t, we should consider asking them to step aside if someone else might be able to do so.”
By the end of the meeting, they had a roadmap to get the cost of each engine down from $2 million to $200,000 in twelve months.
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“I give people hardcore feedback, mostly accurate, and I try not to do it in a way that’s ad hominem,” he says. “I try to criticize the action, not the person. We all make mistakes. What matters is whether a person has a good feedback loop, can seek criticism from others, and can improve. Physics does not care about hurt feelings. It cares about whether you got the rocket right.”
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He thinks that when people want to prioritize their comfort and leisure they should leave.
That’s what Hughes did in May 2022. “Working for Elon is one of the most exciting things you can do, but it doesn’t allow time for a lot else in your life,” he says. “Sometimes that’s a great trade. If Raptor becomes the most affordable engine ever created and gets us to Mars, then it may be worth the collateral damage. That’s what I believed for more than eight years. But now, especially after the death of our baby, it’s time for me to focus on other things in life.”
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“It’s like Machiavelli taught,” Krebs replied. “You have to have fear and love for the leader. Both.”
That attitude would sustain Krebs for another two years. But by Spring 2023, he would become another refugee from Musk’s hardcore all-in approach. After getting married and having a child, he decided it was time to move on and find a better work-life balance.