I tried posting this three times elsewhere - it never saw the light of
day - I'll post an abbreviated version here - enjoy! lol.
* * *
The problem with EMP is over-stated. EMP occurs with very large nuclear
blasts, 20 megatons or more, at an altitude of 20 to 40 km, when a very
large gamma ray burst scatters electrons off the thin atmosphere over a
large area. Those electrons recombine coherently to make a huge
Smaller explosions, Hiroshima and Nagasaki are 20 kt and are 1/1,000th
the size of this explosion, didn't produce EMP.
Explosions of the size of the Orion spacecraft would be less than 2 kt,
and the EMP effects would be nearly non-existant.
Also, Helios type spacecraft, like that proposed by Freeman Dyson,
totally enclose the nuclear explosion in a nozzle that absorbs all the
energy of the propelling explosion. So, there's no chance at all in
creating an EMP.
Now, Helios had proposed a sort of nuclear pulse thrust chamber that
wasn't every efficient. And people have said that this inefficiency is
a necessary feature of total enclosure. That's not exactly true.
Performance, as always, depends on details.
A supersonic nozzle, one where the propellant starts supersonically and
continues flowing supersonically, has many of the features of the Orion
pusher plate, while still affording total enclosure. Imagine a pulse
from a small bomblet originating at the focal point of a parabola. The
wave of energetic material strikes the parabolic pusher plate, and
causes a directed wave to exit the base of the nozzle. This is
distinctly different than say using a nuclear explosion to heat a large
amount of propellant that is then expanded through a conventional
nozzle. It has many of the advantages of Orion type pusher plates, but
is more efficient in many ways - and totally eliiminates EMP.
By compounding the nuclear pulse WITHOUT a fissile materials, we can
create a relatively clean exhaust. Boron-10 and Protium ignited by
3*10^15 anti-protons - about 5 nanograms - can generate energetic
pulses of between 2 tonne TNT equiv. to 2,000 tonne TNT equivalent.
Detonating these tiny pulse units at a rate of 20x per second, we can
lift vehicles ranging in size from 2,000 tonnes to 2,000,000 tonnes and
carry 50% of this mass throughout the solar system.
Boron-10 & Protium produce alpha particles only. No neutrons, no gamma
rays. Helium-4 that's it, at 8.54 MeV per reaction.
A particle accelerator the size of Fermilab could be built specifically
to produce anti-protons. Penning traps made of solid state materials
can be made to efficiently store and transport the needed anti-protons,
and deliver them in a form that is concentrated enough - in time and
space - to exceed the Lawson criterion and setup a detonation wave in
the Borton-10/Protium mix. Since hydrogen and boron can unite
chemically to form borohydrides, these bomblets need not be too
Since 20% of the world's supply of Boron, extracted mostly from Borax
in Turkey and elsewhere, the world might produce 50,000 tonnes of
Boron-10/Hydride per year at fairly reasonable costs. At 75 MJ per
gram - equivalent to the energy contained in 12 barrels of oil, this
50,000 tonnes per year of material could yeild 21x more energy than we
now produce by burning oil.
This is enough energy to fly thousands of the very large rockets and
millions of the smaller rockets. In any case, we have the means to
develop industrially the entire solar system.