Re: Fusion Propulsion

On Mar 4, 12:26 pm, "Williamknowsbest" <William.M...@xxxxxxxxx> wrote:
On Mar 2, 9:02 pm, "Williamknowsbest" <William.M...@xxxxxxxxx> wrote:

Consider the reaction;

p + 11B ---> 3 4He + 8.54 MeV

It requires that the protium and boron-11 be united with an energy of
123 KeV.

Basically, take some Boron-11 toss it in the air, and hit it dead
center with a proton travelling at 5 km/sec. Out will fly 3 Helium-4
nucleii at 12,000 km/sec!

I envision a nano-structured propulsive skin that consists of a layer
of water, a nanoscale hydrogen processing surface that electrolyzes
the water and ionizes the hydrogen, leaving oxygen gas. Then there's
a 160 KV accelerator gap that accelerates the protons to the needed
speed of 5 km/sec injecting them into the fusion system.

The protons enter a photonic-like crystal to control the flow of
particles giving precise control to the desired collision with the
Boron-11. These crystal rods - which have a nanotube like structure
at their center, penetrate a boron layer.

Another nanoscale surface processes the Boron-11 and ejects atoms one
at a time, injecting them at 0.5 km/sec into the same tube.

Despite their high speed along the length of the tube, the nanotube
structure reduces their temperature relative to one another.
Basically, their centers are co-located to within 0.01 angstroms
despite their high closing speed along the length of the tube.

Also, strong electret based fields along the length of the nanotube
like structgure orient the spin of the nuclei so that when the two
nucleii interact, the plane of high probability decay is well defined
and the directions of the emitted particles are controlled..
Nanostructures -again similar to photonic crystals- accept these
particles and redirect their energy so they are all collimated with
very little energy loss while imparting momentum to the entire
structure.

Imagine a 10 cm x 10 cm panel 10 cm thick. There is a 2.33 cm thick
layer of water massing 233 grams capable of producing. 25.8 grams. A
3 cm thick layer of boron-11 penetrated with nanoscale tubes every
micrometer, contains 284 grams of boron-11. The rest of the nanoscale
structure masses 1 kg and carries out the processes on a nanoscale
just described. The final surface has a beam of highly collimated
alpha particles travelling at 12,000 km/sec..

At peak power output the accelerator is 40 MW and it produces a jet
with a 2.3 GW power rating producing 35 kg of thrust across 100 sq cm
- at this level of thrust the system operates 10,000 seconds.

A vehicle with a propulsive skin totalling 320 sq m and weighing
14,000 kg can pull over 8 gees at full thrust. At 1 gee it can
operate 1 day. At 1/10th gee it can operate over a week and fly
throughout the inner solar system. At 1/100th gee the vehicle can
operate 80 days and span the solar system.

In an atmosphere it can use the alpha stream to heat the air it finds
and use it as a working fluid in a combustionless jet - operating at
very low power levels. Thus the vehicle operates like a vtol fighter
in the atmospheres of Earth, Mars, Venus, the outer planets, and moons
with atmospheres.

The oxygen produced by the separation of oxygen and hydrogen from
water is sufficient to support a crew of 6 even at 1/200th gee. A
small quanity of hydrogen is cycled through fuel cells to recreate
water, to power the cabin systems. Spare oxygen is dumped for
evaprative cooling.

Propusive systems like this produced in quantity, would sell for about
$100 per square meter - about $32,000 - if they are to be used as
commonly as automobiles. This means that a square cm costs a penny.
Since 100 sq cm produces over 2GW this means 1 sq cm produces 20
MW!!! A sq mm producs 200 kW!!! And 100 of them cost a penny!!! At
1/1000th output each sq mm produces 2kW - enough to run a house - and
last 1 million seconds - or 11.6 days. A penny pack would power a
home for 3 years!!! Of course, they'd sell for more than a hundred
for a penny.

The 8.54 MeV alpha particle could easily be converted to electrical
power. A 10 cm nanotube like structure that the collimated alpha
particles enter is equipped with structured electric fields that cause
the particles to wiggle. And the wiggler changes spacing as the alpha
particles slow, so that a constant output is produced. A short
segment of material exists at the exhaust plane of the propulsive skin
described earlier to extract power for the 160 KeV injector. In power
applications this is extended to extract all the kinetic energy from
the alpha particles. This results in a powerful IR laser beam
operating at 1100 nm. This laser beam falls on a bandgap matched
Silicon PV device 1 sq mm in area. 2 kW per sq mm is 20,000x solar
intensity. 400 junctions operate in series reducing parasitic heating
16,000x - conversion efficiency is 98% - which means 40 W thermal is
generated for a 2 kW power cell. The PV and power handling equipment
costs 1/10th cent per cell. So, for power application you only get 9
per penny.

Since 1,100 nm is shortwave IR energy, letting the IR energy fall on a
hollow tapered rod of tungten will provide radiant heat - and
depending on surface area (length and diameter of rod) and power level
incandescent lighting.

Power output ranges over 6 orders of magnitude by varying injection
rates from 1,000 per second to 1 billion per second - across each sq
mm. So power output ranges from 2 kW to 2 milliwatts -Longevity
ranges from 11.6 days to 3,000 years for each 5 cm long rod.

A 1 sq cm collection consisting of 100 units 15 cm long costing 11
cents can power a 285 hp electric automobile for two weeks or more
depending on average power rating.

Clearly technology like this could remake life on Earth. Small
appliances could provide energy for every toy, appliance, electronic
device, vehicle, home, office, factory, equipment, on demand.

Every kg of boron produces the equivalent of 11,000 bbls of oil worth
of energy. The world would need 20 kg of boron a day to meet ALL of
its energy needs. The world produces 421,284.8 kg of boron-11 each
day. So, there is plenty of boron-11 to go around. Everyone
consuming energy at current US per capita rate would increase
consumption to 220 kg boron per day. Everyone having their own
personal VTOL spaceship in their garage to fly around the world in
minutes, to the moon in hours and to Mars in days, would increase
boron consumption to about 4,000 kg per day - or about 1% of current
production.

Global economic output is approximately $65 trillion per year and
energy consumption is about $1.8 trillion per year. Increasing this
100 fold implies energy consumption of $180 trillion per year and a
human economy of $1.3 quadrillion per year. At a selling price of 10
penny per watt - an today's consumption of 16 TW - implies $1.6
trillion in infrastructure - a disposable system that lasted about a
year is implied by these numbers. Growing to 100x this figure.

With an economic growth rate of 7% per year, a 100 fold increase in
economic activity would take;

LN(100)/LN(1.07) = 68.06 years

So, by 2075 AD starting today

To reach the current per capita level of the average American requires

LN(11)/LN(1.07) = 35.44 years

Or 2042.

Since population growth rate is inversely proportional to per capita
income, and since the US today has a negative population growth rate
(not counting immigration) we can estimate global population by
assuming it is today's rate until US per capita income is reached.
This step function will over-estimate the total, so we divide the
increase by two as a first-order approximation, so here goes;

Global population today is 6.52 billion and growth rate is 1.14% per
year. So,

Population estimate at ZPG = 6.52e+9 * (1.0114)^(35.44)
= 9.74e+9

This is an increase of 3.22 billion. Dividing this by two obtains
1.61 billion increase. Thus by 2042 given development and broad use
of this technology to bring about a 7% growth rate each year (nearly
doubling today's economic growth rate) population would stabilize at
8.13 billion people.

Delays in implementation increases population and dlays the point in
time ZPG is reached. But generally 10 billion people max by 2050 with
everyone at current US per capita income is a worthy and achievable
target for today's and future industrialists

Thrown into the bargain is the ability to travel throughout the world
and the solar system with the same ease the average American travels
across North America.

The proton is fired at the 11B at 500 km/sec not 5 km/sec since fusion
requires at least 123 KeV collision.

Metaboric acid in beta phase with depleted boron with a density of
2.045 g/cc and a melting point of 201 C has a formula of HBO2 - can
act as a propellant in the system described. Each cc has a potential
energy of 40 GJ - equal to 335 gallons of gasoline!

A MEMs based system admits the metaboric acid into it and decomposes
it into Hydrogen, Boron and oxygen. The oxygen is gathered into a
header system collected and used for breathing as described before.

The Boron is ejected first by the MEMs system across a 300KV gap into
the photonic crystal fiber at 228 km/sec. The proton is ejected next
and it enters the fiber at 750 km/sec behind the boron.

The proton strikes the boron in excess of 500 km/sec.

The position of the strike along the line of travel is determined by
the timing of the two release events. In this simplified systems the
alpha particles are produced in a spherically symmetric pattern at a
well defined point along their mutual line of travel. Scattering of
the alpha particles off the surface produces thrust.

Imagine a 10 cm long channel and detonation 10 cm beyond the end of
this channel. A total travel of 20 cm. At 228 km/sec it takes the
boron atom 877 nanoseconds to traverse this distance. It takes the
proton 267 nanoseconds. So releasing the proton precisely 610 ns
after the boron nucleus across this 300KV gap produces a reaction 20
cm from the release point - 10 cm outside the 10 cm long channel. A 1
micrometer diameter channel, allows 1 million channels per square
mm. At 1 million cycles per second that's 1 trillion reactions per
second per square mm. And at 8.54 MeV per reaction this is an energy
density of;

1 eV = 1.6e-19 J

1e+12 reactions per sq mm

8.54e+6 eV per reaction

So,

8.54e+18 eV per second * 1.6e-19 J/ev = 1.36 Watts per sq mm.

That's 136 Watts per sq cm
That's 1.36 MW per sq m.

This is about 1/20,000th that needed to produce the levels of thrust
called for in the previous example. Although it would make a handy
power system, Reducing the diameter of the channels to 10 nm each,
and multiplying the atomic injectors on the MEMs surface to match
this, increases the reaction rate 10,000x - or 13.6 kW per sq mm, 1.36
MW per sq cm, and 13.6 GW per sq m

Reducing the lengths of the channels to 5 cm and the offset from the
surface to 5 cm, produces the power levels called for in the first
example.

Changing the injection rate of the nuclei changes power output. If 8
gees is 2,000,000 cps then 1 gee would be 250,000 cps. 1/10th gee
25,000 cps. 1/100th gee 2,500 1/200th gee 1,250 cps

Low levels of thrust through interplanetary space produce audible
feedback through the structure. Scattering causes heating effects and
regions of the propulsive surface to glow. Operation in air causes
halo glow. A well designed craft would use atmospheric effects to
sustain lift at very low power settings.

Let's engage in a bit of fantasy...


An ovoid disc shaped craft with thick polyethylene skin penetrated
every 10 nm with a fiber channel of the type described here, with each
fiber fed by a MEMs based injector that takes depleted metaboric acid
(beta phase) and produces oxygen along with generating 11-boron nuclei
and proton streams from the fiber channels, to produce 3 alpha
particles with a combined energy of 8.54 MeV - at a rate sufficvient
to generate up to 3500 kg per sq m of thrust.

Each sq meter masses 100 kg of fusion systems described here, that are
5 cm thick and is backed by a 20 cm thick layer of metaboric acid in a
segmented tank covering the entire inner surface of the vehicle.
Massing another 500 kg for the metaboric acid. The outermost layer,
penetrated by crystal fiber channels every 10 nm is 40 kg of
polyethelyne (UHMWPE) per sq meter - 4.3 cm thick.

So, an ovoid disk consisting of an aluminum skin, with a 20 cm thick
tank surrounding the entire surface, 5 cm of fiber crystals and high
voltage accelerator and mems based injector, and a 4.3 cm thick layer
of ultra-high density polyethelyene. Massing 320 kg per sq m.

So, the total mass is 640 kg per square meter and the total thrust
capable of 3500 kg per sq m. With half the surface producing thrust
the maximum take off thrust is somewhat less than 2.73 gees - for the
empty vehicle. 1.37 gees maximum takeoff acceleration fully loaded.

Assuming the propulsive skin and structure is one half the total mass
of the vehicle, another 640 kg of payload is carried per square meter
of surface area. Thus a disc 22 m in diameter and 10 m thick at the
center with 640 sq m of surface area can produce masses 819,200 kg of
which 409,600 kg is craft, and 409,600 is payload. 320,000 kg is
metaboric acid. 232,700 kg of this represents an oxygen supply for
the cabin.

Load per unit volume is double that of large aircraft like the B747.
Total capacity is 9x that of a B747. In appearance it may look
something like this (without the vortex)

http://media.popularmechanics.com/images/tb_saucer-lg.jpg

With an exhaust velocity of 12,000 km/sec ideal terminal velocity of a
819,200 kg aircraft with 320,000 kg propellant is;

Vf = Ve * LN(1/(1-u)) and u = Mp / Mt

u = 320,000 / 819,200 = 0.39

Vf = 12,000 * LN(1/(1-0.39)) = 5,943 km/sec

At full acceleration this will require; t = V/a = 5,943,000 / 9.82
= 604,800 seconds --> 7.00 days
At 1 gee acceleration - 20 days
At 1/10th gee acceleration - 200 days
At 1/100th gee acceleration - 2000 days

Distances span the inner solar system in a matter of days
Span the outer solar system in a matter of weeks to months

3200 cubic meters of volume is 5x the volume of a 747 cabin. 1000
passengers with full spacesuit and gear can be carried across the
solar system by this vehicle. Cargo versions carry 400 tons of useful
payload. 2,000 lbs of oxygen per day are needed with 1,000 passengers
- obtining this from the metaboric acid requires that no less than
1/5th gee be pulled during transit. This provides a 100 day supply.
500 passengers can operate at 1/10th gee for 200 days.

The skin structure and fuel choice provides substantial radiation
protection during transit. Quick transit times through the inner
solar system (hours to the moon and days to Mars at 1 gee) also avoids
substantial radiation loads. Actually 1/3 gee for a mars bound flight
along with a 1/6 gee for a moon bound flight allow passengers in
transit to acclimate to the local gravity at their destination.

1,000 people per day can be sent to Mars with a fleet of 14 - assuming
reasonable turn around. The same fleet could send 7,000 people per
day to the moon. Supplies would require an additional 6 freighter
versions of this craft. With 1 ton per person year on the moon and
mars using current technology, 200 tons per day to mars supports
73,000 people, and 1,400 tons per day to the Moon supports 510,000
people. Shifting the fleet from passenger to freighter after 70 days
provides for expansion of this population. Once each colony has
learned to 'live off the land' by growing food, generating their own
air, their own water and so forth, from local resources, shifting back
to passenger configurations from freighter configurations allow
continued expansion of the populations on each world. Self-generated
population growth, by those born on each of these worlds would tend to
increase freighter needs. High value products returning to Earth
would permit recovery of some value during the dead-head flights
back. Tourists flights would also allow use of passenger craft to
generate revenue without shifting use patterns - and the returning
tourists would fill the passenger craft. About half the capacity for
a two week flight would imply a 7,000 tourists population in place and
183,000 tourists per year for mars, and 49,000 tourists in place and
1.27 million tourists per year for the moon. Increasing tourism from
these figures to nearly double these figures are sufficient to keep
the fleet busy without major investments, and permit as long a period
of time as needed to grow beyond the 73,000 on Mars and the 510,000 on
the moon permanent populations - possible with this fleet of
spacecraft.

So, we're talking about 50 spacecraft total. 20 allocated to Mars, 14
passenger and 6 freighter. 20 allocated to the moon, divided the same
as mars, and 10 allocated for general solar system support. 5 of
these are freighter configuration, 2 are for deep space long-duration
tourists (think round the world cruise of several months) and 3 are
configured for scientific & research missions.

At a cost of $5 billion each, this is a total of $250 billion.
Another $330 billion is estimated to be the capital requirements for
the support infrastructure on Earth to build out the colonies and
support the engineering efforts to solve the problems of living on the
moon and mars, and maintain human presence across the solar system.




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