Robert Bussard

Robert W. Bussard (August 11, 1928 – October 6, 2007) was an American physicist who worked primarily in nuclear fusion energy research. He was the recipient of the Schreiber-Spence Achievement Award for STAIF-2004. He was also a fellow of the International Academy of Astronautics and held a Ph.D. from Princeton University.

In June, 1955 Bussard moved to Los Alamos and joined the Nuclear Propulsion Division's Project Rover designing nuclear thermal rocket engines. Bussard and R.D. DeLauer wrote two important monographs on nuclear propulsion, Nuclear Rocket Propulsion and Fundamentals of Nuclear Flight.

In 1960, Bussard conceived of the Bussard ramjet, an interstellar space drive powered by hydrogen fusion using hydrogen collected with a magnetic field from the interstellar gas. Due to the presence of high-energy particles throughout space, much of the interstellar hydrogen exists in an ionized state (H II regions) that can be manipulated by magnetic or electric fields. Bussard proposed to "scoop" up ionized hydrogen and funnel it into a fusion reactor, using the exhaust from the reactor as a rocket engine.

It appears the energy gain in the reactor must be extremely high for the ramjet to work at all; any hydrogen picked up by the scoop must be sped up to the same speed as the ship in order to provide thrust, and the energy required to do so increases with the ship's speed. Hydrogen itself does not fuse very well (unlike deuterium, which is rare in the interstellar medium), and so cannot be used directly to produce energy, a fact which accounts for the billion-year scale of stellar lifetimes. This problem was solved, in principle, according to Bussard by use of the stellar CNO cycle in which carbon is used as a catalyst to burn hydrogen via the strong nuclear reaction

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