The LEAP-X (Life Extension and Prolongation) Program was a U.S. military experiment to keep a human in a state of veritable immortality via machines. Since the time of its inception, the experiment was still at its infancy.
John-Caleb Bradberton, founder of the Nuka-Cola Corporation was able to learn of LEAP-X's existence, due to his powerful influence in the American government. He would later bargain with General Braxton to gain access to the LEAP-X project in exchange for supplying his company's resources into Project Cobalt. Unfortunately for Bradberton, the experiment was only able to preserve his head for the next two centuries.