Stored ionized gas for ion drives.
Robert Clark
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/hbase/chemical/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
Uncle Al
>
> 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.
3) Learn something. The first time is a thrill,
http://www.neofuel.com/optimum/
http://www.neofuel.com/optimum/Fig_HEO_MarsHO_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 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.
Thereby demonstrating you don't know crap about powering a space
vessel with an ion drive..
[snip hopeless confusion]
> Then this would provide a means of testing relativistic effects on
> macroscopic bodies.
Idiot.
http://arxiv.org/abs/astro-ph/0609417
http://www.oakland.edu/physics/mog29/mog29.pdf
Deeply relativistic pulsar binary PSR J0737-3039A/B
16.8995 deg/yr periastron advance
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2
dlzc
On Sep 20, 1:47 pm, Robert Clark <rgregorycl...@yahoo.com> 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?
A plasma. Like the Sun, or what is being attempted in fusion power
generation.
...
> The question is could we get light weight means
> of storing large amounts of ionized gas?
No. Not without "Star Trek" containment fields.
...
> 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?
So far, more than the energy is required to contain the plasma than we
get out of fusing the nucelii. And a considerable spray of neutrons
to boot, making the material structures radioactive in the short term.
David A. Smith
BradGuth
speak)
- Brad Guth -
Robert Clark
> ...
> http://www.neofuel.com/optimum/http://www.neofuel.com/optimum/Fig_HEO_MarsHO_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 key fact here is that this is assuming you have to get the fuel
supply on the way and that we can get as *much as we want*:
"We can only deliver a fixed amount of energy to the propellant. How
much? "As much as we can." Material properties and mission thrust
profiles constrain the energy delivered to the propellant to be a
fixed value, namely, as much energy as we can generate during the time
we have and using the heat or energy source we have. We try to design
the fixed amount of energy to be as large as we know how to design. We
always try to deliver as much energy as we can.
"The fundamental question is the choice of propellant exhaust
velocity. If we choose a high velocity then we will deliver the
energy to a small amount of propellant, and we will only need a small
amount of propellant. If we choose a low velocity then we will need a
large mass of propellant. Conventional rocket science abhors results
which demand a large amount of rocket propellant. In our case, we dock
with the space gas station and take on as much as we figure.
...
"Highest velocity" is the rocket scientist's incorrect answer. The
rocket scientist uses "specific impulse" as the measure of velocity.
Velocity = specific impulse x 9.8 meters per second per second. The
incorrect answer "highest specific impulse" is the equivalent to
putting all the available energy into as small a propellant mass as is
practical. The highest energy per mass means the highest specific
impulse.
"This question of exhaust velocity was irrelevant and academic until 3
sept 1998, when Binder, Feldman et al. published the Lunar Prospector
data. The Lunar Prospector data suggested the possible existence of up
to 1e10 tons (ten billion) of relatively pure ice veins at these moon
poles. INEEL published system calculations showing how to deliver
kiloton quantities per year of ice or water from these poles to a
lunar escape orbit, or to a stationary orbit far from the moon. The
possibility of a gas station in space makes this question of "what
exhaust velocity" relevant."
This scenario he is discussing here wouldn't apply to the case where
you are limited by the amount of fuel you can carry and still reach
ultra high velocities, i.e., a significant fraction of the speed of
light.
In any case he concludes:
"optimum Vsp ~ delta-V * 0.6275.....
This means that the best propellant exhaust velocity is about 2/3 of
the mission delta-V (.6275 is approximately 2/3)."
So following his argument if we wanted a final velocity 10% light
speed, 30,000 km/s, we should make the exhaust velocity 20,000 km/s,
even higher than what I was suggesting.
> > 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.
>
> Thereby demonstrating you don't know crap about powering a space
> vessel with an ion drive..
>
Think about it. You have electrostatic method of accelerating a
charge. A heavier molecule is going to move *slower*. It's how mass
spectrometers work. The reason why heavier ions are used for the ion
drive is the limits on the amount of power you have for ionizing the
gas. For this, you have to actually look at the energy levels required
to ionize the specific elements.
> > Then this would provide a means of testing relativistic effects on
> > macroscopic bodies.
> http://arxiv.org/abs/astro-ph/0609417http://www.oakland.edu/physics/mog29/mog29.pdf
> Deeply relativistic pulsar binary PSR J0737-3039A/B
> 16.8995 deg/yr periastron advance
>
Observing relativistic effects essentially in the lab on macroscopic
bodies would be much more interesting than through astronomical
observations, especially if you yourself could be one of the
macroscopic bodies.
Bob Clark
BradGuth
> 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 -
BradGuth
> > terms of the charge on the ions and the voltage driving theionflow:
>
> >Ionthruster.
> >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.
> 3) Learn something. The first time is a thrill,
>
> "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 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.
>
> Thereby demonstrating you don't know crap about powering a space
> vessel with aniondrive..
>
> [snip hopeless confusion]
>
> > Then this would provide a means of testing relativistic effects on
> > macroscopic bodies.
>
> Idiot.
>
> Deeply relativistic pulsar binary PSR J0737-3039A/B
> 16.8995 deg/yr periastron advance
>
> --
> (Toxic URL! Unsafe for children and most mammals)http://www.mazepath.com/uncleal/lajos.htm#a2
On Pep 20, 3:14 pm, BradGuth <bradg...@gmail.com> 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 that are on the move as is. A sufficient payload of
radium as contained within a breeder reactor is what offers such an
ongoing decay of producing those highly interjetic atoms of radon, on
the fly sort of speak.
A high pressure vessel of Pu239 pumped Radium(Ra226) as the breeder
reactor on behalf of obtaining the most Radon (Rn222) or rather LRn222
per given kg of radium isn't hardly rocket science, although as Uncle
Al having restipulated that essentially a nifty byproduct of such a
hot reactor could rather easily become a nice volume or potential kgf/
kg worth of super heated steam ions, of which h2o at 1000 bar at the
nuclear reactive boosted thermal temperature of perhaps 1000 K isn't
exactly of no reaction usage, is it.
- Brad Guth -
Uncle Al
>
> On Pep 20, 3:14 pm, BradGuth <bradg...@gmail.com> 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.
Idiot.
http://www.mazepath.com/uncleal/horse.htm
--
Uncle Al
BradGuth
> BradGuth wrote:
>
> > On Pep 20, 3:14 pm, BradGuth <bradg...@gmail.com> 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.
>
> [snip crap]
>
> Idiot.
Wow, one of Hitlers incest cloned Third Reich minions is very much
alive and kicking at anything that's in sight.
What's your silly little topic/author fuckology problem this time
around?
What exactly do you folks have against a 1600+ year half life of Rn222
ion fuel along with a rather nifty thermal energy supply that'll
seriously kick rocket butt via ions and if need be a little steam.
Sorry, I'd forgot that you're just being your usual naysay upon
anything that wasn't your idea to start with, or even if it was your
idea that's being in any way utilized by anyone else is apparenly that
much worse off.
- Brad Guth -
Jerry
> 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_HEO_MarsHO_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?
The standard rocket equation analysis remains unchallenged for
vehicles that need to carry all of their own propellant from
the beginning of launch...
...which is pretty much all current rockets. At some future date,
new technologies such as scramjets may allow more fuel-efficient
launches, but once outside of the atmosphere, the standard
rocket equation analysis will inevitably come back into play
(absent development of such pure science-fictional fantasies as
Bussard ramjets).
"Maximum achievable specific impulse" is here to stay.
Jerry
John Savard
<rgrego...@yahoo.com> wrote, in part:
> 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?
No.
Basically, while things like "electrets" have been manufactured, it's
*really, really* difficult to insulate against electrical current well
enough to keep a tank of gas ionized over a long space flight.
Just not even worth considering.
John Savard
http://www.quadibloc.com/index.html
BradGuth
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 -
BradGuth
> 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 -
Robert Clark
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 here:
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
BradGuth
> On Sep 21, 1:50 am, BradGuth <bradg...@gmail.com> wrote:
>
> > On Pep 20, 3:14 pm, BradGuth <bradg...@gmail.com> 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 here:
>
>
> 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 -
Robert Clark
> 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:
>
>
> 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:
>
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
BradGuth
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 -