From Earth To Mars In As
Little As Two Weeks?

BEER-SHEVA, ISRAEL - Scientists at Ben-Gurion University have shown that an unusual nuclear fuel could send space vehicles from Earth to Mars in as little as two weeks. Spacecraft now take between eight and 10 months to make the same trip.
The research shows a fairly rare nuclear material, americium-242m (Am-242m), when used as an extremely thin metallic film, is capable of sustaining nuclear fission. When the film is less than a thousandth of a millimetre thick, the high-energy, high-temperature products of fission can escape the fuel and be used for propulsion in space.
Obtaining fission-fragments like this isn't possible with the better-known uranium-235 and plutonium-239 nuclear fuels: they require large fuel rods, which absorb fission products.
Long-time interest
Dr. Yigal Ronen, the author of the study, became interested in nuclear reactors for space vehicles 15 years ago at a conference. Speaker after speaker talked about the use of nuclear reactors for powering space missions - and stressed that the mass of any reactor would be the defining factor. It had to be light in order to be efficient.
So Ronen decided to examine one aspect of reactor design - the nuclear fuel itself. That led him to Am-242m.
By using this element, Ronen was able to cut the amount of fuel necessary to reach maximum power. To achieve the same result as uranium or plutonium requires only one per cent of the amount (mass) when Am-242m is used.
But use of this fuel is still in the very early stages of development. "There are still many hurdles to overcome before americium-242m can be used in space," Ronen says.
Producing large quantities of Am-242m requires several steps and is expensive. Design of the reactor, refuelling, heat removal and safety provisions also need to be examined.
In spite of the hurdles, Ronen remains optimistic about the future of this fuel. "I am sure that americium-242m will eventually be implemented for space travel, as it is the only proven material whose fission products can be made available for high speed propulsion."
The study was published in Nuclear Instruments and Methods in Physics Research A (455: 442-451, 2000).
From 1-8-01
There are several ways of getting nuclear thrust effects. This method uses the energy of the atom fragments as well. In fission-fusion bombs special beryllium-copper mirrors direct these fission products, X-rays, neutrons, and etc. down beam channels to fire the secondary system.
In the ORNL fireball type reactor much of the relativistic energy is released as well, in the form of neutrons, x-rays, and gamma rays. Similarly, these emissions can be reflected using mirrors from omnidirection emissions into directed emissions. The net effect is similar to ion drive system, except vastly more powerful. Other research uses LASER directed energy onto mirrors to make levitation.
One of the most collosal dreams was "project orion" that intended to use pulsed nuke bombs to loft huge ships into orbit and space. Other nuke engines use rocket fuel and nuke combinations.
Since most of these techniques use relativistic emissions, the net velocity approaches the speed of light.

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