Stored ionized gas for ion drives.

On Sep 22, 12:54 am, Jerry wrote:
On Sep 20, 4:10 pm, Uncle Al wrote:

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

1) p=mv drives the craft.
2) KE=(mv^2)/2 is the price you pay for exhaust changing momentum.
Faster exhaust is stooopid.

Try learning to THINK before you cry "stoopid", Al.

3) Learn something. The first time is a thrill,

http://www.neofuel.com/optimum/
http://www.neofuel.com/optimum/Fig_H...HO_sloStmr.gif
"a steam rocket would produce nearly the optimum specific impulse for
transporting the largest payload from a high Earth orbit to a high
Mars orbit. Higher specific impulses (600 - 900 seconds) such as are
achievable using liquid hydrogen propellant typically result in at
least an order of magnitude poorer performance."

The analysis that you cite specifically denies a basic assumption of
the rocket equation:
"The condition for this conclusion is that the propellant be separate
from the rocket system and used in operations similar to a gas
station.
This conclusion to use 'limited specific impulse' instead of the
traditional 'maximum achievable specific impulse' depends entirely on
being able to launch a rocket system separate from the propellant, and
that the amount of propellant used from a propellant "gas station"
does not pose operational issues."

How are you going to arrange for "gas stations" along the way to
Mars, Al?

Using my LSE-CM/ISS as the fuel and everything else depot/gateway
should more than do the trick. How many thousand tonnes of fuel or
that of a little spare Pu239 and good old radium for accommodating
those impressive Rn222 ion thrusters, would you like?

I might even be able to supply h2o and salt.
- Brad Guth -

On Sep 20, 1:47 pm, Robert Clark wrote:

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?

You bet, because there's nothing more ionized as is than radon (Rn222)
gas, or even a cache of LRn222 to start off with, which can also be
made while on the fly (sort of speak).
- Brad Guth -

On Sep 21, 1:50 am, BradGuth wrote:
On Pep 20, 3:14 pm, BradGuth wrote:

Why store ion worthy gas when it can be made on the fly? (sort of
speak)

Hot radon gas is actually a fairly active resource or cache of
impressive ions as is. A sufficient payload of radium as a breeder
reactor is what offers such decay of producing radon on the fly.

A high pressure Pu239 pumped Radium(Ra226) breeder reactor on behalf
of obtaining the most Radon (Rn222) or rather LRn222 per kg of radium
isn't hardly rocket science.
- Brad Guth -

This could work. A problem would be the radioactive products
produced in the exhaust. An advantage though is the energy for ion
acceleration can be produced from the energy of the radioactive
decay.
A similar idea is proposed he

Fission-fragment rocket.
http://en.wikipedia.org/wiki/Fission-fragment_rocket

This is a currently feasible system that could also achieve exhaust
velocities of 1,000,000 m/s. Perhaps the problem of radioactive
exhaust could be solved by having the fission fragments collide with a
nonradioactive propellant mass to produce the thrust and the
radioactive products bouncing back to be used again to impart momentum
to the propellant.

Bob Clark

On Sep 22, 8:07 am, Robert Clark wrote:
On Sep 21, 1:50 am, BradGuth wrote:

On Pep 20, 3:14 pm, BradGuth wrote:

Why store ion worthy gas when it can be made on the fly? (sort of
speak)

Hot radon gas is actually a fairly active resource or cache of
impressive ions as is. A sufficient payload of radium as a breeder
reactor is what offers such decay of producing radon on the fly.

A high pressure Pu239 pumped Radium(Ra226) breeder reactor on behalf
of obtaining the most Radon (Rn222) or rather LRn222 per kg of radium
isn't hardly rocket science.
- Brad Guth -

This could work. A problem would be the radioactive products
produced in the exhaust. An advantage though is the energy for ion
acceleration can be produced from the energy of the radioactive
decay.
A similar idea is proposed he

Fission-fragment rocket.http://en.wikipedia.org/wiki/Fission-fragment_rocket

This is a currently feasible system that could also achieve exhaust
velocities of 1,000,000 m/s. Perhaps the problem of radioactive
exhaust could be solved by having the fission fragments collide with a
nonradioactive propellant mass to produce the thrust and the
radioactive products bouncing back to be used again to impart momentum
to the propellant.

Bob Clark

In space travels of once having left that basic LEO, there's not to
worry about whatever's the amount or density of Rn222 ion exhaust, and
of that robust mass of exhaust velocity which could easily become
worth 30,000 km/s, if not faster, would always be far enough away
obviously directed away from whatever crew that would be well enough
shielded by the robust breeder reactor itself that's simply too hot to
touch. (such IR photons are not all that humanly bad, nor all that
insurmountable to shield against)

The Pu239 pumped Ra226--Rn222 is clearly a use-it or lose-it kind of
highly reactive ion gas breeder, that'll subsequently demanding the
least amount of applied energy for making such ions every bit as super-
ionized and directed or focused as those exit grids can withstand.
- Brad Guth -

On Sep 22, 8:07 am, Robert Clark wrote:
On Sep 21, 1:50 am, BradGuth wrote:

On Pep 20, 3:14 pm, BradGuth wrote:

Why store ion worthy gas when it can be made on the fly? (sort of
speak)

Hot radon gas is actually a fairly active resource or cache of
impressive ions as is. A sufficient payload of radium as a breeder
reactor is what offers such decay of producing radon on the fly.

A high pressure Pu239 pumped Radium(Ra226) breeder reactor on behalf
of obtaining the most Radon (Rn222) or rather LRn222 per kg of radium
isn't hardly rocket science.
- Brad Guth -

This could work. A problem would be the radioactive products
produced in the exhaust. An advantage though is the energy for ion
acceleration can be produced from the energy of the radioactive
decay.
A similar idea is proposed he

Fission-fragment rocket.http://en.wikipedia.org/wiki/Fission-fragment_rocket

This is a currently feasible system that could also achieve exhaust
velocities of 1,000,000 m/s. Perhaps the problem of radioactive
exhaust could be solved by having the fission fragments collide with a
nonradioactive propellant mass to produce the thrust and the
radioactive products bouncing back to be used again to impart momentum
to the propellant.

Bob Clark

For some pesky reason my poor old PC and usenet access is getting robo/
stealth moderated to death, so I'm having to repost the same message
more than once. Sorry about that.

In space travels of once having left that basic LEO, there's not to
worry about whatever's the amount or density of Rn222 ion exhaust, and
of that robust mass of exhaust velocity which could easily become
worth 30,000 km/s, if not faster, would always be far enough away and
obviously directed away from whatever crew that would be well enough
shielded by the robust breeder reactor itself that's simply too hot to
touch. (such IR photons are not all that humanly bad, nor all that
insurmountable to shield against)

The Pu239 pumped Ra226--Rn222 is clearly a use-it or lose-it kind of
highly reactive ion gas breeder, that'll subsequently demanding the
least amount of applied energy for making such ions every bit as super-
ionized and directed or focused as those exit grids can withstand.
- Brad Guth -

On Sep 22, 8:07 am, Robert Clark wrote:
On Sep 21, 1:50 am, BradGuth wrote:

On Pep 20, 3:14 pm, BradGuth wrote:

Why store ion worthy gas when it can be made on the fly? (sort of
speak)

Hot radon gas is actually a fairly active resource or cache of
impressive ions as is. A sufficient payload of radium as a breeder
reactor is what offers such decay of producing radon on the fly.

A high pressure Pu239 pumped Radium(Ra226) breeder reactor on behalf
of obtaining the most Radon (Rn222) or rather LRn222 per kg of radium
isn't hardly rocket science.
- Brad Guth -

This could work. A problem would be the radioactive products
produced in the exhaust. An advantage though is the energy for ion
acceleration can be produced from the energy of the radioactive
decay.
A similar idea is proposed he

Fission-fragment rocket.http://en.wikipedia.org/wiki/Fission-fragment_rocket

This is a currently feasible system that could also achieve exhaust
velocities of 1,000,000 m/s. Perhaps the problem of radioactive
exhaust could be solved by having the fission fragments collide with a
nonradioactive propellant mass to produce the thrust and the
radioactive products bouncing back to be used again to impart momentum
to the propellant.

Bob Clark

Accumulated as stored radon gas for ion drives:
Even on behalf of the launch phase, I'm not all that certain there'd
be that much actual Radon radiation if merely standing near that fast
moving exhaust, however once having reached LEO, and as for serious
space travels there's certainly not to worry about whatever's the
radiation potential within any amount, density or velocity of that
narrow focused stream or perhaps nearly Rn222 ion laser beam worth of
exhaust flow.

That robust ion mass of terrific exit velocity could easily become
worth 30,000 km/s, if not a whole lot greater as a radon ion pumped
laser cannon might suggest a maximum exit velocity of 150,000 km/s,
would always be situated far enough away and obviously its exhaust or
beam like flow of such ions being directed away from whatever crew,
that would most likely be situated as well enough shielded by the
robust breeder reactor itself, that's simply running a little too hot
to humanly touch. (the last time I'd checked, IR photons are not all
that bad, nor all that insurmountable to shield against)

The ion worth of joules per 2 mg of Rn222 ions, if those were exiting
at 30,000 km/s, as based upon KE=.5MV2 = 1e-6 * 9e14 = 9e8 joules (the
same as 25 KW.h, roughly an hours worth of 34 SHP or the terrestrial
measured force of 9.177e6 kgf.m)

The Pu239 pumped Ra226--Rn222 is clearly a use-it or lose-it kind of
highly reactive ion gas breeder, that'll subsequently demand the least
amount of applied energy for making such ions of Rn222 every bit as
super-ionized and rather easily directed or focused as those fast
moving ions exit via whatever those acceleration grids can withstand.
(magnetic fields might keep such ions from ever contacting those
grids)
- Brad Guth -

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 current ion 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. The 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 Pure Ion Plasma In A Cylindrical Current Sheet.
http://www.pppl.gov/pub_report//2000/PPPL-3403.pdf

Bob Clark

On Sep 28, 5:53 pm, Robert Clark wrote:
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 current ion 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. The 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 Pure Ion Plasma In A Cylindrical Current Sheet.http://www.pppl.gov/pub_report//2000/PPPL-3403.pdf

Argue or rant all you want, as this anti-think-tank of usenet
naysayism doesn't really give a puck about ions. However, I do,
because the use of such fast moving ions is still our best alternative
once in LEO, or far better yet from my LSE-CM/ISS that's tethered near
to the moon's L1, whereas it takes next to nothing for a given launch
on behalf of damn near any amount of mass. (1e6 tonnes could be safely
launched on it mary way with as little as one gram/sec of force)
- Brad Guth -