Uploaded November 2025 | Updated September 2026, 1 week ago
Developing a rocket is already one of the hardest engineering challenges on Earth. Everyone knows that. But what most people don’t realize is that the real nightmare isn’t the giant tanks, or the shiny metal booster. The real troublemaker is the engine. That’s the part that decides whether a rocket becomes a historic achievement… or an expensive metal tower that never leaves the ground.
Think about it for a second. You can design the smartest rocket in the world, build a booster the size of a skyscraper, give it advanced computers, beautiful carbon fiber structures—none of that matters if the engines don’t work. Without engines, rockets can’t lift a single inch off the planet. They’re basically very expensive lawn ornaments.
That’s why rocket engines are usually the most expensive part of the entire vehicle. In many cases, they make up something like seventy percent of the total cost. Seriously—if a rocket costs, say, $60 million to build, the engines alone might be around $40 million of that. That’s how brutally complex they are.
And it’s also why so many companies refuse to develop their own engines. They’ll build the rocket, they’ll build the launch pad, they’ll build everything else—but when it comes to engines, they outsource. ULA, for example, buys its BE-4 engines directly from Blue Origin instead of developing its own. Because building engines from scratch is risky, slow, expensive, and full of opportunities for things to go very, very wrong.
Developing a rocket is already one of the hardest engineering challenges on Earth. Everyone knows that. But what most people don’t realize is that the real nightmare isn’t the giant tanks, or the shiny metal booster. The real troublemaker is the engine. That’s the part that decides whether a rocket becomes a historic achievement… or an expensive metal tower that never leaves the ground.
Think about it for a second. You can design the smartest rocket in the world, build a booster the size of a skyscraper, give it advanced computers, beautiful carbon fiber structures—none of that matters if the engines don’t work. Without engines, rockets can’t lift a single inch off the planet. They’re basically very expensive lawn ornaments.
That’s why rocket engines are usually the most expensive part of the entire vehicle. In many cases, they make up something like seventy percent of the total cost. Seriously—if a rocket costs, say, $60 million to build, the engines alone might be around $40 million of that. That’s how brutally complex they are.
And it’s also why so many companies refuse to develop their own engines. They’ll build the rocket, they’ll build the launch pad, they’ll build everything else—but when it comes to engines, they outsource. ULA, for example, buys its BE-4 engines directly from Blue Origin instead of developing its own. Because building engines from scratch is risky, slow, expensive, and full of opportunities for things to go very, very wrong.
