Physicist's New Fission
Power Cuts Mars Trip
From 3 Years To 45 Days
By Rossella Lorenzi
Discovery Channel Online
A nuclear-powered engine could someday shorten a spacecraft's journey to Mars from three years to only 45 days.
That's according to Professor Carlo Rubbia, winner of the 1984 Nobel Prize for Physics. He says his brainchild could open the way to a systematic exploration of our planetary system by humans.
"Nuclear energy on Earth is competing with many other alternatives and is not without problems, but in deep-space travel it offers unique possibilities," says Rubbia, introducing his project during a recent conference at CERN, the European particle physics laboratory in Geneva.
Indeed, nuclear energy seems to be the innovative ingredient in any recipe for deep-space exploration, though none of the propulsion tools considered so far has been able to offer a quick ticket to Mars.
With his so-called fission fragment rocket, Rubbia claims he has finally found the solution. Fission fragments are the direct products of a nuclear reaction in which a nucleus is split into fragments, accompanied by a release of energy.
Rubbia's engine is based on this process and on a key element: americium-242. A synthetic chemical element somewhat similar to lead, americium was first derived from plutonium-239 in 1944.
The combustion chamber of Rubbia's engine would be covered with a thin layer of americium-242 whose fission, induced by neutrons, provokes highly ionized fragments. The process continues with hydrogen entering the chamber. The fission fragments pass through hydrogen and the resulting heat creates a powerful propellant.
The energy supplied by 1 gram of americium is about the same as that of 1 ton of the best chemical propellant. A few kilos of americium would be sufficient for a 120-million mile voyage to Mars for a spacecraft and its crew.
"It is a fascinating project. I believe that it is feasible too, as Rubbia is a very competent and trustworthy person," says Margherita Hack, director of the Inter-University Regional Center for Astrophysics and Cosmology in Trieste, Italy.
Rubbia's light and simply structured spacecraft would allow round-trip travel to Mars in a maximum of five months, including the necessary stay on the planet.
"I'm in touch with the Italian and the European space agencies for a possible realization of the engine," says Rubbia. "For Europe this would mean a leading role in future space explorations."