In this image, we see a clear example of technological evolution and improvement. In less than 10 years, Elon Musk's SpaceX went from the engine on the left, filled with parts and ducts, to the engine on the right, which is simpler in design and has more thrust. It's incredible how a private company managed to achieve in 22 years what many government space programs couldn't accomplish in decades.

And an important detail: this engine is reusable!