The Ion Interstellar Spaceship, from Hell to Sirius

What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_engines ,
http://eprints.soton.ac.uk/47966/01/paperColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
.. - Brad Guth

A good source of thruster ions that'll keep coming is from the likes
of Radium that creates the Radon (Rn222) gas. Radium is somewhat
rare, but it is not as an element uncommon. However, of what's most
uncommon is any public disclosures or education about Radium.

Apparently the element of Radium is officially taboo/nondisclosure
rated, especially as far as to who has what and at whatever current
market value. Essentially, this need-to-know market price of Radium
is at least a thousand fold more government cartel hocus-pocus price
fixed than anything of fossil fuels or even of yellowcake, though the
formal extraction process of obtaining roughly 100 milligrams per
yellowcake tonne is essentially a robotic task from start to finish.
For the most part, Radium is actually another one of those discarded
elements within spent nuclear fuel, as well as found at less
concentrations within most mineral tailings or otherwise given as a
slight part of most all fossil fuels, that which the fossil energy
industry as a whole do not bother to extract or otherwise divert this
element from the subsequent CO2/Nox laced combustion soot, much of
which simply goes either directly into our atmosphere or if in full
clean-air compliance merely gets relocated into various landfills
that'll eventually end up eroding and/or blending back into the
general environment. Of course none of the valuable 3He has been
collected either, so what the hell.

Naturally-occurring radioactive materials (NORM)
http://www.eoearth.org/article/Natur...aterials_(NORM)
A great amount of Radium and subsequently Radon comes into our
surface environment though fossil fuel extractions and subsequent
usage, and much of whatever's initially kept from being
atmospherically dispersed as CO2 and NOx contaminated soot that's
laced with a slight trace of Radium is simply buried in relatively
shallow graves or in some cases utilized as fill for open pit mining
site recovery. In other words, most all of the mined elements of
radioactive fuel that used to be safely sequestered far enough
underground, essentially away from our frail DNA and surface
environment, has been systematically and artificially reintroduced
into our life sustaining environment, along with as little public
education as possible so that folks are simply snookered into being
unaware of these surrounding concentrations and dosage levels that we
all have to cope within.

Radon gas; "reportedly causes 21,000 lung cancer deaths per year in
the United States alone."
http://en.wikipedia.org/wiki/Radon
If that be the case, then by any global/world standard could be
looking at as many as 400,000 Radon gas related deaths per year, if
not an all-inclusive 500,000 in radiation contamination related deaths
per year (keeping in mind that fewer than 500 pandemic deaths per year
would become a world health alert with multiple quarantines imposed).
Therefore, rounding up as much of the spare/surplus Radium as possible
seems like a perfectly good sort of task worth doing, so that it can
be either put safely away or at least properly utilized in a manner
that doesn't further traumatize our frail DNA and badly failing
environment any more than absolutely necessary. Like U238 yellowcake
of 80% grade, whereas perhaps the 100 mg/tonne of 90~97% extracted
grade of this refined Radium ore doesn't amount to all that much by
volume, but clearly what there is of it has become extremely valuable
as well as humanly lethal if continually ignored as is, not to mention
what adverse affects are imposed upon all other plant, animal and
microbe forms of life that surrounds and benefits us, and in one way
or another gets involved and/or consumed by us humans.

Radium is roughly 60 fold more radioactive than Uranium, is also of at
least 6 million fold greater worth per equal weight, and obviously the
extremely active Radon(Rn222) decay element is flying right off the
charts.

http://en.wikipedia.org/wiki/Uranium_mining_in_Colorado
"Although no more than a trace of radium was present in the ore, newly
discovered medical applications had made radium worth $100 per
milligram, making the radium in the carnotite ore worth much more than
the vanadium or uranium." (however, we're also talking of those
extremely old dollars worth better than twenty fold of our current
dollar that's not exactly floating)

As of 1940, Radium was made artificially worth as little as $25/
milligram, and as of today our American medical cartel inflated value
of pure Radium metal is always floating closer to whatever the market
or cancer patient will bare, such as $175/milligram (that's actually
relatively dirt cheap compared to what it used to cost in those old
hard earned dollars of nearly a century ago), and with the market
price of yellowcake about to reach $1000/kg within this next decade is
only suggesting that the rare element within of Radium will likely be
in hot pursuit of exceeding the $1000/milligram mark. In the World
there's roughly 100 kg of medical Radium hording (not including secret
amounts held by various governments and of private speculation
hording), and because this Radium salt or metallic alloy can be
utilized over and over thousands of times, and also because of its
given artificial cartel market value is why this element is most
always fully recovered per usage, and as such there's way more than
enough to go around for medical applications, along with more on its
way for those capable of paying the price, because it can be extracted
on demand.

Radium chloride (bromide salt) is less costly to produce or extract
from spent nuclear fuel, than having to create a pure metallic Radium
alloy, but because so many NRC and the medical cartel folks like to
live large, it'll likely still costs you about $500/milligram and even
if need be marked up from there so that their normal 10:1 profit
margins don't suffer. (actually that profit margin is in excess of a
1000:1 if you take into account how many times the same substance gets
reused and thus resold over and over)

http://query.nytimes.com/mem/archive...CF&oref=slogin
The previous Radium cartel market price had once upon a time been as
great as $160,000/gram, and again that was in old 1930 dollars that
were actually worth something.

http://www.time.com/time/magazine/ar...758086,00.html
Monday, Aug. 09, 1937 "A rich radium deposit is one which yields 90
to 120 milligrams (.00315 to .0042 oz.) nearly pure radium bromide
salt per ton of concentrated ore (50 tons of crude ore). From ore
bodies of such richness in northwestern Canada the refining plant is
able to extract one gram of commercially pure radium from 550 tons of
mined ore. A San Diego mining engineer and chemist named F. S.
Kearney, now working in Mexico, assayed Mrs. Bishop's ore at 130
milligrams of radium per ton. This high figure, Mrs. Bishop said, was
confirmed when she sent a sample to the Institut de Radium in Paris
(once presided over by the late Marie Curie). Present price of radium
is $25 per milligram, $25,000 per gram, $700,000 per ounce. Mrs.
Bishop suspected for years that she had radium ore on her property,
kept it quiet until her claim was cleared in the courts. Last week the
excited little woman did not know just how extensive her deposit was,
but she and her lawyers laid plans for a thorough survey and hoped to
write a new chapter in the shifting course of world radium
production."

Just another interesting matter of a good ion generating fact about
smoke detectors: "one Am-241 emitted alpha particle will produce
150,000 ions", so perhaps other than Radium-226 that'll gradually
yield to becoming Rn222, as such can instead be put to good use on
behalf of feeding large scale ion thrusters.

There's actually quite a good amount of Radium226 to behold (because
it's what ever so gradually makes Radon gas, and there's lots of Rn222
to go around), although most of this Radium has not been
systematically collected or much less isolated from our environment,
even though it's extremely valuable. Never the less it's still not
getting officially rounded up at more than 1% of what's otherwise
getting artificially diverted into our badly failing environment, and
perhaps that's the real reason why so little information is published
as to the natural and artificially established inventory of Radium,
much of which is held within existing inventories of yellowcake, in
weapons grade and spent nuclear fuel that no one on Earth seems to
want anything to with unless getting paid hundreds of billions of our
hard earned loot up front. Via fossil fuel explorations, extractions
and various forms of consumption is where much of the naturally
occurring Radium has found its way into our polluted surface and
oceans of growing dead zone environments, and oddly there's still no
technical plan or even spin of action for collecting this element of
Radium that's associated within such fossil fuels and various mineral
tailings. Much like our FEMA in action, the lethal and whatever
valued energy related aspects of Radium is only getting studied to
death, though mostly on behalf of product hording and cover-thy-butt
protecting, for making damn certain that no one in government or
corporate whatever can ever be held accountable. (perhaps they'll end
up blaming everything on Marie Curie, if not Muslims).

At any rate, the extremely active element of Radium is quite
interesting and valuable in far more ways than most realize or are
being allowed to learn about. Whenever I mention the use of Radium is
when the Usenet lights usually go out, and I can here that door
slamming shut. It's almost as taboo/nondisclosure rated as for asking
where the hell that planet Venus was hiding throughout all of those
NASA/Apollo years. Go figure.

Since the Ux U3O8 (aka yellowcake) was recently worth nearly $310/kg
as of June 2007, and is currently hovering at the subsidized mark of
$210/kg, but due to the ongoing global fossil fuel fiasco is likely to
push that U3O8 into LEO at any moment, means that the much greater
spot market value of Radium follows suit at reaching the potential
worth of exceeding $1000/mg. This is obviously good news if you so
happen to own a given cache of Radium, though bad news for your bank
account if your cancer treatments or whatever else involves Radium.
Government tolerated hording and subsequent profiteering is what keeps
Radium spendy and otherwise not getting as well collected as it could
be, whereas the more corrupt our puppet government gets, the more we
get to pay in ways other than just our hard earned loot.

I'll do my best to polish up this information, in order to show how
we've been wasting this Radium resource and otherwise wasting decades
of time that should have been better spent going to/from those nifty
off-world places.
.. - Brad Guth


On Feb 7, 10:40 am, BradGuth wrote:
What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of this
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_eng...ColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
. - Brad Guth

At least Robert Clark isn't against our use of ions for thrust, and of
notions for storing enough of such ions for creating a fairly
substantial amount of volume sustained thrust if given the necessary
energy for accelerating such ions is part of the package deal. Of
course, I've had to correct those usual robo-moderated words as having
been run together, so that a normal key word search would even turn up
this "Stored ionized gas for ion drives" contribution of his, stating
that such ion exhaust/exit shouldn't have any difficulties in
obtaining 10,000 km/s. Whereas I'm thinking the 16.7e3 km/s of the
natural 5.6 MeV radium alpha/ion particle itself is perhaps not half
of what a electrostatic boosted and magnetic focused Rn222 ion could
muster, therefore its potential exit velocity of 34,000 km/s (that's
better than 0.1'c') seems entirely doable, and of the much greater
mass of the Rn222 ion should by rights benefit the thrust potential
without ignoring any of those laws of physics.

http://groups.google.com/group/sci.s...ba7 8d45e7e1b
From: Robert Clark
Date: Sep 28 2007, 4:53 pm
Subject: Stored ionized gas for ion drives.
To: sci.space.policy, sci.astro, sci.physics, sci.physics.relativity,
sci.physics.fusion

On Sep 20, 4:47 pm, Robert Clark wrote:
This page gives a formula for the exhaust speed of an ion engine in
terms of the charge on the ions and the voltage driving the ion flow:

Ionthruster.
http://en.wikipedia.org/wiki/Ion_thruster#Energy_usage

The exhaust speed increases with the charge on the ions and decreases
with their mass. You would think then that a light gas like hydrogen
would be ideal since heavier gases even when fully ionized would still
contain approximately equal numbers of neutrons as protons which would
not contribute to the charge but would approximately double the mass.

Yet it is the heavier gases like cesium and more recently xenon that
are used. The explanation is that of the energy it takes to ionize the
gas used as fuel. The figure on this page shows the energy to ionize a
light gas such as hydrogen is relatively high compared to the heavier
gases:

Ionization Energies.
http://hyperphysics.phy-astr.gsu.edu...al/ionize.html

The figure gives the energy per mole which is high in itself. It is
even worse when you consider this on a per mass basis since the mass
amount of hydrogen would be so small compared to the amount of energy
needed to ionize it.

So could we instead store the hydrogen or some other light gas
already in ionized form so we would not have to supply power to ionize
the gas, only to accelerate it?

If you used ionized hydrogen, so you would be accelerating protons,
then using 6 x 10^18 protons to make one 1 Coulomb, and a mass of 1.6
x 10^-27 kg for a proton, and V representing the voltage in volts, the
speed on the ions (protons) would be about (10^4)sqrt(2*V) in meters/
second.

If we made the voltage be 5,000 V we would get 1,000,000 m/s speed
much higher than any currentiondrive. Also, there are power supplies
that convert low voltage high amperage power into high voltage, low
amperage power, even up to 500,000 V. Then we could get 10,000,000
m/s = 10,000 km/s exhaust speed.

The question is could we get light weight means of storing large
amounts of ionized gas? Note that is this for space based propulsion
not launch from Earth. You would have a possibly large energy
generating station that remained in low Earth orbit to supply the
power to ionize the gas once the spacecraft was placed in orbit. The
power generator would be left behind in orbit. Then the volume of the
gas container could be large to keep the density of the gas low. This
would allow very thin container walls. Note the low density would also
allow the electrostatic repulsion of the positively charged ions to be
more easily constrained.

A possible problem though is the charged ions contacting the walls
could lead to a loss of ionization. You might be able to use a low
level magnetic field to prevent the ions contacting the walls. Low
density of the gas would insure the strength of the magnetic field
required would be low. It might even be accomplished by thin permanent
magnets so you would not need to use extra power.

Some questions: what would be the electrostatic pressure produced by
a low density highly ionized gas? What strength magnetic field would
you need to contain it?

Note that with an exhaust speed of say 10,000 km/s, by the rocket
equation we could get the rocket itself up to relativistic speeds with
acceptable mass ratios.

Then this would provide a means of testing relativistic effects on
macroscopic bodies.
Bob Clark


There is a lot of research on containing charged particles of only
one charge, that is, all positive or all negative, because of fusion
research. These are called "non-neutral" plasmas.

There is a limit on the number of charged particles you can contain
in a magnetic trap based on the strength of the magnetic field called
the "Brillouin limit."

However, some researchers have argued it is possible to exceed
This limit:

Confinement Of PureIonPlasma In A Cylindrical Current Sheet.
http://www.pppl.gov/pub_report//2000/PPPL-3403.pdf
Bob Clark

Perhaps others might care to ponder and subsequently offer their best
swag(scientific wild ass guess) as to our getting the most out of ion
thrust, not that Ra226-Rn222 need be the one and only alternative.
However, with that nearby and gamma saturated moon of ours might
actually suggest there's a good amount of Radium to behold, and at a
$1M/gram seems entirely worth going after, more so than whatever 3He.
(why the hell not accomplish extracting both?)
.. - Brad Guth


On Feb 8, 7:59 am, BradGuth wrote:
A good source of thruster ions that'll keep coming is from the likes
of Radium that creates the Radon (Rn222) gas. Radium is somewhat
rare, but it is not as an element uncommon. However, of what's most
uncommon is any public disclosures or education about Radium.

Apparently the element of Radium is officially taboo/nondisclosure
rated, especially as far as to who has what and at whatever current
market value. Essentially, this need-to-know market price of Radium
is at least a thousand fold more government cartel hocus-pocus price
fixed than anything of fossil fuels or even of yellowcake, though the
formal extraction process of obtaining roughly 100 milligrams per
yellowcake tonne is essentially a robotic task from start to finish.
For the most part, Radium is actually another one of those discarded
elements within spent nuclear fuel, as well as found at less
concentrations within most mineral tailings or otherwise given as a
slight part of most all fossil fuels, that which the fossil energy
industry as a whole do not bother to extract or otherwise divert this
element from the subsequent CO2/Nox laced combustion soot, much of
which simply goes either directly into our atmosphere or if in full
clean-air compliance merely gets relocated into various landfills
that'll eventually end up eroding and/or blending back into the
general environment. Of course none of the valuable 3He has been
collected either, so what the hell.

Naturally-occurring radioactive materials (NORM)http://www.eoearth.org/article/Natur...oactive_materi...)
A great amount of Radium and subsequently Radon comes into our
surface environment though fossil fuel extractions and subsequent
usage, and much of whatever's initially kept from being
atmospherically dispersed as CO2 and NOx contaminated soot that's
laced with a slight trace of Radium is simply buried in relatively
shallow graves or in some cases utilized as fill for open pit mining
site recovery. In other words, most all of the mined elements of
radioactive fuel that used to be safely sequestered far enough
underground, essentially away from our frail DNA and surface
environment, has been systematically and artificially reintroduced
into our life sustaining environment, along with as little public
education as possible so that folks are simply snookered into being
unaware of these surrounding concentrations and dosage levels that we
all have to cope within.

Radon gas; "reportedly causes 21,000 lung cancer deaths per year in
the United States alone."http://en.wikipedia.org/wiki/Radon
If that be the case, then by any global/world standard could be
looking at as many as 400,000 Radon gas related deaths per year, if
not an all-inclusive 500,000 in radiation contamination related deaths
per year (keeping in mind that fewer than 500 pandemic deaths per year
would become a world health alert with multiple quarantines imposed).
Therefore, rounding up as much of the spare/surplus Radium as possible
seems like a perfectly good sort of task worth doing, so that it can
be either put safely away or at least properly utilized in a manner
that doesn't further traumatize our frail DNA and badly failing
environment any more than absolutely necessary. Like U238 yellowcake
of 80% grade, whereas perhaps the 100 mg/tonne of 90~97% extracted
grade of this refined Radium ore doesn't amount to all that much by
volume, but clearly what there is of it has become extremely valuable
as well as humanly lethal if continually ignored as is, not to mention
what adverse affects are imposed upon all other plant, animal and
microbe forms of life that surrounds and benefits us, and in one way
or another gets involved and/or consumed by us humans.

Radium is roughly 60 fold more radioactive than Uranium, is also of at
least 6 million fold greater worth per equal weight, and obviously the
extremely active Radon(Rn222) decay element is flying right off the
charts.

http://en.wikipedia.org/wiki/Uranium_mining_in_Colorado
"Although no more than a trace of radium was present in the ore, newly
discovered medical applications had made radium worth $100 per
milligram, making the radium in the carnotite ore worth much more than
the vanadium or uranium." (however, we're also talking of those
extremely old dollars worth better than twenty fold of our current
dollar that's not exactly floating)

As of 1940, Radium was made artificially worth as little as $25/
milligram, and as of today our American medical cartel inflated value
of pure Radium metal is always floating closer to whatever the market
or cancer patient will bare, such as $175/milligram (that's actually
relatively dirt cheap compared to what it used to cost in those old
hard earned dollars of nearly a century ago), and with the market
price of yellowcake about to reach $1000/kg within this next decade is
only suggesting that the rare element within of Radium will likely be
in hot pursuit of exceeding the $1000/milligram mark. In the World
there's roughly 100 kg of medical Radium hording (not including secret
amounts held by various governments and of private speculation
hording), and because this Radium salt or metallic alloy can be
utilized over and over thousands of times, and also because of its
given artificial cartel market value is why this element is most
always fully recovered per usage, and as such there's way more than
enough to go around for medical applications, along with more on its
way for those capable of paying the price, because it can be extracted
on demand.

Radium chloride (bromide salt) is less costly to produce or extract
from spent nuclear fuel, than having to create a pure metallic Radium
alloy, but because so many NRC and the medical cartel folks like to
live large, it'll likely still costs you about $500/milligram and even
if need be marked up from there so that their normal 10:1 profit
margins don't suffer. (actually that profit margin is in excess of a
1000:1 if you take into account how many times the same substance gets
reused and thus resold over and over)

http://query.nytimes.com/mem/archive...9A01E5DD1E38E6...
The previous Radium cartel market price had once upon a time been as
great as $160,000/gram, and again that was in old 1930 dollars that
were actually worth something.

http://www.time.com/time/magazine/ar...758086,00.html
Monday, Aug. 09, 1937 "A rich radium deposit is one which yields 90
to 120 milligrams (.00315 to .0042 oz.) nearly pure radium bromide
salt per ton of concentrated ore (50 tons of crude ore). From ore
bodies of such richness in northwestern Canada the refining plant is
able to extract one gram of commercially pure radium from 550 tons of
mined ore. A San Diego mining engineer and chemist named F. S.
Kearney, now working in Mexico, assayed Mrs. Bishop's ore at 130
milligrams of radium per ton. This high figure, Mrs. Bishop said, was
confirmed when she sent a sample to the Institut de Radium in Paris
(once presided over by the late Marie Curie). Present price of radium
is $25 per milligram, $25,000 per gram, $700,000 per ounce. Mrs.
Bishop suspected for years that she had radium ore on her property,
kept it quiet until her claim was cleared in the courts. Last week the
excited little woman did not know just how extensive her deposit was,
but she and her lawyers laid plans for a thorough survey and hoped to
write a new chapter in the shifting course of world radium
production."

Just another interesting matter of a good ion generating fact about
smoke detectors: "one Am-241 emitted alpha particle will produce
150,000 ions", so perhaps other than Radium-226 that'll gradually
yield to becoming Rn222, as such can instead be put to good use on
behalf of feeding large scale ion thrusters.

There's actually quite a good amount of Radium226 to behold (because
it's what ever so gradually makes Radon gas, and there's lots of Rn222
to go around), although most of this Radium has not been
systematically collected or much less isolated from our environment,
even though it's extremely valuable. Never the less it's still not
getting officially rounded up at more than 1% of what's otherwise
getting artificially diverted into our badly failing environment, and
perhaps that's the real reason why so little information is published
as to the natural and artificially established inventory of Radium,
much of which is held within existing inventories of yellowcake, in
weapons grade and spent nuclear fuel that no one on Earth seems to
want anything to with unless getting paid hundreds of billions of our
hard earned loot up front. Via fossil fuel explorations, extractions
and various forms of consumption is where much of the naturally
occurring Radium has found its way into our polluted surface and
oceans of growing dead zone environments, and oddly there's still no
technical plan or even spin of action for collecting this element of
Radium that's associated within such fossil fuels and various mineral
tailings. Much like our FEMA in action, the lethal and whatever
valued energy related aspects of Radium is only getting studied to
death, though mostly on behalf of product hording and cover-thy-butt
protecting, for making damn certain that no one in government or
corporate whatever can ever be held accountable. (perhaps they'll end
up blaming everything on Marie Curie, if not Muslims).

At any rate, the extremely active element of Radium is quite
interesting and valuable in far more ways than most realize or are
being allowed to learn about. Whenever I mention the use of Radium is
when the Usenet lights usually go out, and I can here that door
slamming shut. It's almost as taboo/nondisclosure rated as for asking
where the hell that planet Venus was hiding throughout all of those
NASA/Apollo years. Go figure.

Since the Ux U3O8 (aka yellowcake) was recently worth nearly $310/kg
as of June 2007, and is currently hovering at the subsidized mark ...

read more

Hmmm, seems we can't even honestly rant about ion thrusting for the
fun of it all. Go figure, even though ion thrusters that reliably and
efficiently work according to those pesky laws of physics are
currently rather small, there's no good reason(s) as to why they can't
be made as terribly huge and extremely powerful.

Of course, it would be nice having my LSE-CM/ISS as our space depot/
gateway or outpost oasis for the assembly of such nifty spaceships
with those big ion thrusters, but then that's also technically
doable.
.. - Brad Guth

On Feb 11, 10:47 am, BradGuth wrote:
Hmmm, seems we can't even honestly rant about ion thrusting for the
fun of it all. Go figure, even though ion thrusters that reliably and
efficiently work according to those pesky laws of physics are
currently rather small, there's no good reason(s) as to why they can't
be made as terribly huge and extremely powerful.

Of course, it would be nice having my LSE-CM/ISS as our space depot/
gateway or outpost oasis for the assembly of such nifty spaceships
with those big ion thrusters, but then that's also technically
doable.
. - Brad Guth

as of "Feb 11 by BradGuth - 11 messages - 6 authors"

So, why are these other "6 authors" hiding form sci.space.history?
.. - Brad Guth

This is rather odd: The Ion Interstellar Spaceship, from Hell to
Sirius
"Feb 11 by BradGuth - 11 messages - 6 authors"

So, where exactly are these other 5 authors hiding out, if not posting
into any of the following groups?

sci.space.history, sci.space.policy, sci.space.shuttle, alt.astronomy,
sci.physics.particle

Are the Usenet moderator bots hard at work (removing whatever they
don't like), or what?
.. - Brad Guth


BradGuth wrote:
What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_engines ,
http://eprints.soton.ac.uk/47966/01/paperColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
. - Brad Guth

Apparently I'm on the right track about more than is permitted by the
Gods of Usenet. Something about an ion thruster using a breeder
pumped cache on behalf of Ra226 that'll make Rn222 as a reliable
supply of fast moving ions capable of 0.1'c' or better exit velocity,
is obviously pushing more of those do-not-push buttons. If not Ra226-
Rn222, then perhaps any number of other fast moving ions via
radioactive substances seems doable, whereas the required energy of
diverting and focus of such active ions seems rather efficient,
especially if they are laser cannon pumped into such a narrow focus.

"Feb 11 by BradGuth - 13 messages - 6 authors" As of somewhere within
all of sci.space.history, sci.space.policy, sci.space.shuttle,
alt.astronomy, sci.physics.particle indicates that a few authors had
been contributing to this topic of "The Ion Interstellar Spaceship,
from Hell to Sirius", but lo and behold something else has been
extracting those contributions of these authors, somewhat like my
email being continually screwed with.

If you're one of those five attempting to contribute, but wondering as
to why I'm not replying to your message, and the same goes for my
email, then don't blame me because, I'll always read and reply to whom
ever's constructively contributing to the topic.
.. - Brad Guth


On Feb 7, 10:40 am, BradGuth wrote:
What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_eng...ColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
. -BradGuth

Big time ion thrust is what'll get our future probes and eventually
ourselves to/from those distant places.

Even Pb gas ions are usable, although requiring a good amount of
energy for converting whatever Pb208(lead) into a gas of ions to start
with may be more or less counter productive, especially when Rn222
ions can be derived from the decay of Ra226 as is without the need of
introducing extra energy, and even the breeder cache of Ra226 that's
pumped along by a Th232 fueled reactor may in fact become a darn good
resource of energy, as well as offering a rather good breeder
alternative at maximizing those various decay processes.

At least Robert Clark isn't another one of those typical anti-think-
tank naysayers in charge of banishing any such bulk use of ions for
thrust, and of notions for storing enough of such ions (such as
LRn222) for creating a fairly substantial amount or volume sustained
thrust if given the necessary energy for accelerating such ions is
part of the package deal. Of course, I've had to correct a few of
those usual robo-moderated words as having been run together, so that
a normal key word search would even turn up this "Stored ionized gas
for ion drives" contribution of his, stating that such ion exhaust/
exit shouldn't have any difficulties in obtaining 10,000 km/s.
Whereas I'm thinking the 16.7e3 km/s of the natural 5.6 MeV radium
alpha/ion particle itself is perhaps not half of what a electrostatic
boosted and magnetic focused Rn222 ion could actually muster,
therefore its potential exit velocity of 34,000 km/s (that's better
than 0.1'c') seems entirely doable, and of utilizing the much greater
mass of those extremely active Rn222 ions should by rights benefit
this thrust potential without ignoring any of those laws of physics.

http://groups.google.com/group/sci.s...ba7 8d45e7e1b
From: Robert Clark
Date: Sep 28 2007, 4:53 pm
Subject: Stored ionized gas for ion drives.
To: sci.space.policy, sci.astro, sci.physics, sci.physics.relativity,
sci.physics.fusion

On Sep 20, 4:47 pm, Robert Clark wrote:
This page gives a formula for the exhaust speed of an ion engine in
terms of the charge on the ions and the voltage driving the ion flow:

Ion thruster.
http://en.wikipedia.org/wiki/Ion_thruster#Energy_usage

The exhaust speed increases with the charge on the ions and decreases
with their mass. You would think then that a light gas like hydrogen
would be ideal since heavier gases even when fully ionized would still
contain approximately equal numbers of neutrons as protons which would
not contribute to the charge but would approximately double the mass.

Yet it is the heavier gases like cesium and more recently xenon that
are used. The explanation is that of the energy it takes to ionize the
gas used as fuel. The figure on this page shows the energy to ionize a
light gas such as hydrogen is relatively high compared to the heavier
gases:

Ionization Energies.
http://hyperphysics.phy-astr.gsu.edu...al/ionize.html

The figure gives the energy per mole which is high in itself. It is
even worse when you consider this on a per mass basis since the mass
amount of hydrogen would be so small compared to the amount of energy
needed to ionize it.

So could we instead store the hydrogen or some other light gas
already in ionized form so we would not have to supply power to ionize
the gas, only to accelerate it?

If you used ionized hydrogen, so you would be accelerating protons,
then using 6 x 10^18 protons to make one 1 Coulomb, and a mass of 1.6
x 10^-27 kg for a proton, and V representing the voltage in volts, the
speed on the ions (protons) would be about (10^4)sqrt(2*V) in meters/
second.

If we made the voltage be 5,000 V we would get 1,000,000 m/s speed
much higher than any currention drive. Also, there are power supplies
that convert low voltage high amperage power into high voltage, low
amperage power, even up to 500,000 V. Then we could get 10,000,000
m/s = 10,000 km/s exhaust speed.

The question is could we get light weight means of storing large
amounts of ionized gas? Note that is this for space based propulsion
not launch from Earth. You would have a possibly large energy
generating station that remained in low Earth orbit to supply the
power to ionize the gas once the spacecraft was placed in orbit. The
power generator would be left behind in orbit. Then the volume of the
gas container could be large to keep the density of the gas low. This
would allow very thin container walls. Note the low density would also
allow the electrostatic repulsion of the positively charged ions to be
more easily constrained.

A possible problem though is the charged ions contacting the walls
could lead to a loss of ionization. You might be able to use a low
level magnetic field to prevent the ions contacting the walls. Low
density of the gas would insure the strength of the magnetic field
required would be low. It might even be accomplished by thin permanent
magnets so you would not need to use extra power.

Some questions: what would be the electrostatic pressure produced by
a low density highly ionized gas? What strength magnetic field would
you need to contain it?

Note that with an exhaust speed of say 10,000 km/s, by the rocket
equation we could get the rocket itself up to relativistic speeds with
acceptable mass ratios.

Then this would provide a means of testing relativistic effects on
macroscopic bodies.
Bob Clark


There is a lot of research on containing charged particles of only
one charge, that is, all positive or all negative, because of fusion
research. These are called "non-neutral" plasmas.

There is a limit on the number of charged particles you can contain
in a magnetic trap based on the strength of the magnetic field called
the "Brillouin limit."

However, some researchers have argued it is possible to exceed
this limit:

Confinement Of PureIonPlasma In A Cylindrical Current Sheet.
http://www.pppl.gov/pub_report//2000/PPPL-3403.pdf
Bob Clark

Perhaps if those pesky MIB allow, others might care to ponder and
subsequently offer their best swag(scientific wild ass guess) as to
our getting the most out of accomplishing large scale ion thrust, not
that Ra226-Rn222 need be the one and only ion alternative. However,
with that nearby and gamma saturated moon of ours might actually
suggest there's a good amount of lunar Thorium and Radium to behold
(by night there should be LRn222 available), and you'd think Radium at
becoming worth $1M/gram seems entirely worthy of our going after,
perhaps even more so worthy than whatever 3He. (why the hell not
accomplish extracting Th232, Ra226, LRn222 and 3He, as well as
collecting Sodium and making local O2 in the process?)

BTW, for some odd reason this topic has had contributions by 6 authors
(including myself), but oddly none of those other than mine seems to
have be retained by the all-knowing command of those in charge of this
supposed public Usenet.
. - Brad Guth


On Feb 7, 10:40 am, BradGuth wrote:
What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_eng...ColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
. -BradGuth

How interesting, in that the Usenet lights go out and the door slams
shut whenever speaking of seriously big and powerful ion propulsion
alternatives, that by rights of physics and of peer replicated science
should work, and should scale up without limitations.

Clearly those pesky MI5/CIA MIBs are in charge of this Usenet, and
they obviously do not like what some of us outsiders are having to
say.
.. - Brad Guth

Come on folks, this topic needs as many of those Google/NOVA Usenet
gold stars as you can muster.

Ion thrusting isn't even my idea, it just needs to get a whole lot
larger and having a greater cache of those spare/surplus ions to focus
and accelerate to at least 0.1'c'.

Why not a gigaVolt or even a teraVolt grid differential potential, or
that of a laser cannon pumped version of using those Rn222 ions as the
laser plasma gas?
.. - Brad Guth


BradGuth wrote:
What if instead of our going with whatever's small, extremely cheap,
fast and rad-hard robotic, what if going with larger is nearly always
better?

Perhaps this new and improved topic of "Building Spaceships" for
accommodating us frail humans on interstellar treks, and of those
multi generation habitat spacecraft being extensively ion thrusted,
along with the wizardly help of William Mook and those few of us
unafraid of whatever's out there, as such may be a little easier said
than done, not to mention folks having to deal with my dyslexic
encryption and frequent typos that can't always manage to keep those
numbers or terminology half straight.

Perhaps such a large scale ion thrusted spacecraft isn't quite as
insurmountable as we've been told, and it's not that a pair or quad
worth of substantial LRBs would not have to help get this rather
substantial package off the pad (in modules if need be, and assembled
at the moon's L1). However, upon launch and of once reaching the cool
upper most atmosphere is where the potential of ion thrusting could
start to contribute w/o Radon saturating Earth in the process, and
obviously from whatever LEO point onward is where the real potential
of ion thrust becomes impressive, especially since this method of
electro-rocket thrust can be sustained for as long as the given cache
of ions and electrical energy holds out. (with radium-radon there's a
failsafe worth of 1600+ years before reaching half-life, so there's
never a total lack of those Rn222 alpha/ions, and there's even some
electron energy derived from the Radium-Rn breeder reactor)

Given a sufficient cache of hefty ions and a sufficient onboard supply
of electron energy for artificially accelerating and redirecting those
ions into a narrow exit trajectory, and if this thrust is the direct
result of a given ion flow rate or mass of whatever ion particles per
second times the exit velocity squared, as then where's the
insurmountable problem, other than your not standing anywhere behind
those ion thrusters.

Radon just so happens to make for a very good cache of substantially
massive ions that are already quite active/reactive and supposedly
going places as is, at roughly 1.63e7 m/sec. Liquid Radon or LRn222
represents a nifty fluid cache of a easily stored concentration of
Radon gas (though because of its short half-life it's still very much
one of those use it or lose it substances, with possibly an extended
life within a near solid 0 K storage), of which I believe this cache
of Rn222 can be electrically induced or excited into exiting this ion
thruster at a velocity as great as 0.1'c' (perhaps an exit velocity of
0.5'c' is technically doable if we're talking about a radon pumped
laser cannon).

Similar to: http://en.wikipedia.org/wiki/Ion_engines ,
http://eprints.soton.ac.uk/47966/01/paperColettiMPD.pdf
Our lord all-knowing (aka World FactBook) Mook says; "Check it out"
Here is how much thrust a rocket engine produces;
F = mdot * Ve
where mdot = mass flow rate, as kg/sec
Ve = exhaust speed m/sec
F = force (newtons) kg m/sec/sec

Here is how much power a rocket engine's jet produces
P = 1/2 * mdot * Ve^2
That is, the rate at which energy must be added to the exhaust jet is
the kinetic energy of the parts.
- - - -

Of course this is not about any Mook passive alpha particle directing
application, instead taking efficiency of the overall electrical and
ion tossing system into account (such as thermal energy losses) adds
to this existing amount of ion worth via applied electrical and
magnetic energy that'll focus and accelerate those ions. So, it is not
nearly as simple to express as one as Mook might suggest.

However, at the notion of our getting rid of this initial tonne worth
of our liquid cache of LRn222, at the ion mass flow rate of 1 kg/s,
whereas the kinetic power or energy worth of thrust supposedly
becomes:

If the 1 kg/s flow of Rn ions and the exit Ve were made as great as
10%'c' = 3e7 m/s

P = .5 * 9e14 = 4.5e14 kgf

At utilizing this ion exit velocity of 0.1'c' (3e7 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using up one kg/s = 1000 seconds worth of
creating 4.5e14 kgf, of which this substance would push a 4.5e12 kg
(4.5 gigatonne) spacecraft at 100 gee in relationship to the gravity
at the surface of Earth.

At the more realistic ion exit velocity of 1% light speed is
0.01'c' (3e6 m/s)
A metric tonne of LRn that'll essentially become just plain old Rn gas
of pure Rn222 ions, at using one kg/s = 1000 seconds worth of 4.5e12
kgf, of which would push a 4.5e10 kg (45 megatonne) spacecraft at 100
gee in relationship to gravity at the surface of Earth.

Of course the 45 megatonne spacecraft isn't hardly any more likely
than human DNA or whatever spacecraft structurally surviving 100 gee.

So, to start off with we'd likely have ourselves a whole lot smaller
than 45 megatonne spacecraft, such as perhaps only as great as 4.5
megatonnes that'll exit away from Earth at perhaps as great as 10 gee,
then once 10r (63,730 km and just 1% Earth gravity) is reached,
whereas this is when the ion exit velocity could be safely punched up
from 0.001'c' to 0.01'c', and eventually the maximum of 0.1'c' could
be applied to as little as using a gram of Rn222 per second, because
at 0.1'c' or better exit velocity is where you really do not require
all that much mass flow per second.

0.1% light speed is 0.001'c' = 3e5 m/s

1 kg/sec at 3e5 m/s = .5 * 9e10 = 4.5e10 kgf

4.5e10 kgf would push a 4.5e6 tonne spacecraft along at 10 gee

Using a gram/sec:
4.5e7 kgf would push a 4.5e6 tonne spacecraft along at 0.1 gee

I believe that 1000 seconds of 10 gee acceleration is worth 78.4 km/s,
though of course we'd be past the 10r of Earth within the first 600
seconds, and thereby able to ion whiz past that 78.4 km/s mark like it
was standing still.

This next part is often where my math takes yet another nose dive, but
since I do not have the fly-by-rocket software and none others that
claim as always being all-knowing are seldom willing to share, is why
I'll just have to make do, especially since even the warm and fuzzy
likes of Mook always takes the lowest road possible in order diminish
and/or disqualify whatever isn't of his idea to start off with,
excluding just enough of the good stuff in order to foil any further
thought process.

The required energy for a given thousand seconds worth of accelerating
those Rn222 ions up to 3e5 m/s isn't exactly insignificant, demanding
perhaps at least 245.2 GW.h (8.826 e14 J) for accommodating all 16.7
minutes worth of ion thrust. However, due to the overall efficiency
of this energy transfer into accelerating those Rn ions is why it'll
more than likely demand somewhat greater energy for accomplishing this
task of tossing out the entire tonne worth those Rn222 alpha ions at
the rate of one kg/s, even if that's initially accomplished at this
minimal 0.001"c". However, since the existing Rn alpha particle
velocity is already self motivated at 1.6e7 m/s(.054'c'), perhaps
along with given another 5.6 MeV boost is where the required energy
can be limited as to whatever's necessary for accomplishing a good
exit focus or creating that laser cannon like beam, in which case the
required ion thruster energy could become relatively minimal for
accomplishing an impressive exit ion velocity of 3.26e7 m/s.

At times this spacecraft is going to require a hole lot more
electrical energy than any cache of Radium to Radon reactor could
manage at 32 kw/Ra tonne, or even 320 kw/breeder Ra tonne. However,
at a gross spacecraft mass of 4.5e6 tonnes, there's no problem with
incorporating an h2o2/aluminum fuel cell of 100 GW.h capacity, or
accommodating whatever Lithium nanotube ion battery storage, nuclear
reactors or fusion alternatives.

Once trekking off into interstellar space, and especially upon getting
this craft past our nearest interstellar L1, and of the other gravity
pulling us towards the likes of the relatively massive Sirius star/
solar system that we're already in blueshift as headed towards Sirius,
as this is when as little as a mdot microgram/sec of Rn222 at the exit
velocity of 0.2'c' would be more than sufficient ion thrust for
continually accelerating this 4.5e6 tonne spacecraft towards the
gravity pull of Sirius.

For a one microgram/sec of Rn222 mdot at 0.2'c' example:
P = .5e-9 * 3.6e15 = 1.5e6 kgf (1,500 tonnes/s of thrust, or in this
case 0.000333 gee)

The next problem gets down to the business of continually building up
another cache of LRn from the Ra-Rn breeder reactor while on the fly,
on behalf of that pesky matter of our having to ion retrothrust long
before overshooting the intended target. At 4.5e9 kg, stopping this
sucker that's by now going like a bat out of hell (possibly having
reached 0.1'c') is going to take some doings. Of course, there would
be generations of new and improved minds onboard in order to figure
most of this out before arriving into the Sirius star/solar system,
not to mention whatever could have been transmitted from Earth over
the past century.

BTW, at this point of topic argument sake, this mission to Sirius is a
one way ticket to ride, with absolutely no travel package guaranties
or ticket refunds allowed, because we may not be able to sufficiently
retrothrust in order to save any of those brave souls, and a purely
gravity-well trajectory turn-around or that of sufficiently
aerobraking is at best iffy, although a substantial solar wind
parachute as brake might eventually work. Also, recall the sheer size
of these required ion thrust nacelles, as being somewhat Star Trek
Enterprise like, and for all we know in need of those lithium crystals
or perhaps lithium nanotubes as part of their function (after all, any
good science fiction uses the regular laws of physics and the best
available science, and for all we know lithium could still be part of
it).
. - Brad Guth