SpaceX didn’t just improve rocket engines — they reinvented them. From the Falcon 9’s Merlin to the full-flow staged-combustion Raptor engine, this is how Elon Musk’s team changed spaceflight forever.

Reusable rockets have reshaped the economics of spaceflight by dramatically reducing the cost of launching payloads into orbit. Traditional rockets were single-use vehicles that burned up or crashed ...