Rocket scientists agree that we have about reached the limit of our ability to travel in space using chemical rockets. To achieve anything near the speed of light we will need a new energy source and a new propellant. Nuclear fission is not an option.

History has repeatedly shown that when a new method or material becomes available, new uses for it arise.

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.

Wilson Greatbatch Quotes