Part 8/12:
Following Falcon 1’s success, Mueller shifted focus to the larger Falcon 9, which featured nine Merlin engines. He spearheaded the development of new engine variants, including the Merlin 1D, which revolutionized spaceflight through its reliability, simplicity, and cost-effectiveness.
Most notably, Mueller engineered deep throttle capabilities into the Merlin engine. This innovation enabled the controlled landing and reuse of rocket boosters—a feat that the aerospace industry considered nearly impossible. The first successful booster landing in 2015 proved space reusability was achievable at scale, drastically reducing launch costs.