Nuclear fusion of light elements like hydrogen or helium would permit approaching the speed of light. It seems very attractive to refuel your space ships where the fuel is.

E. Wilson Greatbatch (September 6 1919 – September 27 2011) was an American engineer and inventor. The cell used two elements at near ends of the electrochemical scale causing a high voltage of 2.

Wilson Greatbatch (September 6 1919 – September 27 2011) was an American engineer and inventor.