- 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