The main problem with Active Shielding is the polarity of the field.
Since the radiation leaving the sun is positive a positive field will
repel the particles, but at the same time it will accelerate every
electron in the vincinity of the habitat towards it. The resulting
shower on the hull of the habitat will produce enough X-Rays to kill
anyone inside.

You can arrange a magnetic field to deflect the electrons, but I'm
wondering what the weight of the material, and the power utilization
is. All the power is heat that has to be radiated away. This means
more radiators.

How much real savings in weight is there, remembering that the passive
sheild will be waste material from industrial processes in space, and
the active sheilding material will probably be sent up from earth.

Just a Thought,

Bill

--- In spacesettlers@egroups.com, "Combs, Mike"
> From: Tom Tucker (Olympia) [mailto:tntucker@c...]
>
> From: Dr. Omni
>
> It seems that youre a proponent of Active Shielding - the use of
magnetic
> and electric fields to protect your habitat. What are the
disadvantages that
> you see with Passive Shielding - simply covering your habitat with a
layer
> of rock (or ice, depending on your location in the Solar System) a
few
> meters thick?
>
> Tom - Primarily mass, although inertia will be important.
>
> To me, this would be more of an issue for a travelling structure
than a
> stationary one.
>
> However, I believe that the lowest mass, and hence, largest volume
for
> equal costs, can be achieved using active shielding.
>
> If the shielding is made up of slag left over from your ore refining
> operation, I don't see it adding a lot to the costs, at least not
from a
> material standpoint. I don't think the construction costs would be
as high
> as for the pressure shell, as I think the construction requirements
would
> not be quite as precise as what's needed for a pressure shell.
>
> It would be much better to just turn-up the voltage a bit when a
solar
> flare is due rather than hiding in a shelter IMO.
>
> I think the advantage of the 6' thick shield is that you can just go
about
> your buisiness normally during flares.
>
> A 4 meter tube/elevator becomes a 12 meter dia tube if shielding is
added...
>
> I'd question if shielding was even needed for an elevator tube. The
4-6'
> shielding requirement is for what's safe to live in for the rest of
your
> life. Since one would only spend a short amount of time in the
elevator
> tube, shielding requirements there would probably be somewhat
relaxed.
> Given the nature of primaries/secondaries, no shielding at all may
be best.

Bill,

Yes, there are details that need to be worked out. Lets try a thought experiment. Imagine a dumbell shaped space station with a huge Van De Graff generator separating charges with one end + and the other -. The - end could be sacrificed or perhaps it will contain the nuclear reactor or political prisoners :-) while everyone else is safe in the + end.
If you like this concept, then replace the - end with an electron gun that shoots electrons a long way away past the + charge. Perhaps this gun is located at the end of a tether that also provides some electrical thrust? Think about it.

Tom
From: bill t
To: spacesettlers@egroups.com
Sent: Tuesday, December 19, 2000 5:17 PM
Subject: [spacesettlers] Active Sheilding

The main problem with Active Shielding is the polarity of the field.
Since the radiation leaving the sun is positive a positive field will
repel the particles, but at the same time it will accelerate every
electron in the vincinity of the habitat towards it. The resulting
shower on the hull of the habitat will produce enough X-Rays to kill
anyone inside.

You can arrange a magnetic field to deflect the electrons, but I'm
wondering what the weight of the material, and the power utilization
is. All the power is heat that has to be radiated away. This means
more radiators.

How much real savings in weight is there, remembering that the passive
sheild will be waste material from industrial processes in space, and
the active sheilding material will probably be sent up from earth.

Just a Thought,

Bill

--- In spacesettlers@egroups.com, "Combs, Mike"
wrote:
> From: Tom Tucker (Olympia) [mailto:tntucker@c...]
>
> From: Dr. Omni
>
> It seems that youre a proponent of Active Shielding - the use of
magnetic
> and electric fields to protect your habitat. What are the
disadvantages that
> you see with Passive Shielding - simply covering your habitat with a
layer
> of rock (or ice, depending on your location in the Solar System) a
few
> meters thick?
>
> Tom - Primarily mass, although inertia will be important.
>
> To me, this would be more of an issue for a travelling structure
than a
> stationary one.
>
> However, I believe that the lowest mass, and hence, largest volume
for
> equal costs, can be achieved using active shielding.
>
> If the shielding is made up of slag left over from your ore refining
> operation, I don't see it adding a lot to the costs, at least not
from a
> material standpoint. I don't think the construction costs would be
as high
> as for the pressure shell, as I think the construction requirements
would
> not be quite as precise as what's needed for a pressure shell.
>
> It would be much better to just turn-up the voltage a bit when a
solar
> flare is due rather than hiding in a shelter IMO.
>
> I think the advantage of the 6' thick shield is that you can just go
about
> your buisiness normally during flares.
>
> A 4 meter tube/elevator becomes a 12 meter dia tube if shielding is
added...
>
> I'd question if shielding was even needed for an elevator tube. The
4-6'
> shielding requirement is for what's safe to live in for the rest of
your
> life. Since one would only spend a short amount of time in the
elevator
> tube, shielding requirements there would probably be somewhat
relaxed.
> Given the nature of primaries/secondaries, no shielding at all may
be best.
>
> Regards,
> Mike Combs

Yes, there are details that need to be worked out. Lets try a thought experiment. Imagine a dumbell shaped space station with a huge Van De Graff generator separating charges with one end + and the other -. The - end could be sacrificed or perhaps it will contain the nuclear reactor or political prisoners :-) while everyone else is safe in the + end.
If you like this concept, then replace the - end with an electron gun that shoots electrons a long way away past the + charge. Perhaps this gun is located at the end of a tether that also provides some electrical thrust? Think about it.

Tom
From:
bill t
To:
spacesettlers@egroups.com
Sent:
Tuesday, December 19, 2000 5:17 PM
Subject:
[spacesettlers] Active Sheilding
The main problem with Active Shielding is the polarity of the field.
Since the radiation leaving the sun is positive a positive field will
repel the particles, but at the same time it will accelerate every
electron in the vincinity of the habitat towards it. The resulting
shower on the hull of the habitat will produce enough X-Rays to kill
anyone inside.
You can arrange a magnetic field to deflect the electrons, but I'm
wondering what the weight of the material, and the power utilization
is. All the power is heat that has to be radiated away. This means
more radiators.
How much real savings in weight is there, remembering that the passive
sheild will be waste material from industrial processes in space, and
the active sheilding material will probably be sent up from earth.
Just a Thought,
Bill
--- In spacesettlers@egroups.com, "Combs, Mike"
> From: Tom Tucker (Olympia) [mailto:tntucker@c...]
>
> From: Dr. Omni

>
> It seems that youre a proponent of Active Shielding - the use of
magnetic
> and electric fields to protect your habitat. What are the
disadvantages that
> you see with Passive Shielding - simply covering your habitat with a
layer
> of rock (or ice, depending on your location in the Solar System) a
few
> meters thick?
>
> Tom - Primarily mass, although inertia will be important.
>
> To me, this would be more of an issue for a travelling structure
than a
> stationary one.
>
> However, I believe that the lowest mass, and hence, largest volume
for
> equal costs, can be achieved using active shielding.
>
> If the shielding is made up of slag left over from your ore refining
> operation, I don't see it adding a lot to the costs, at least not
from a
> material standpoint. I don't think the construction costs would be
as high
> as for the pressure shell, as I think the construction requirements
would
> not be quite as precise as what's needed for a pressure shell.
>
> It would be much better to just turn-up the voltage a bit when a
solar
> flare is due rather than hiding in a shelter IMO.
>
> I think the advantage of the 6' thick shield is that you can just go
about
> your buisiness normally during flares.
>
> A 4 meter tube/elevator becomes a 12 meter dia tube if shielding is
added...
>
> I'd question if shielding was even needed for an elevator tube. The
4-6'
> shielding requirement is for what's safe to live in for the rest of
your
> life. Since one would only spend a short amount of time in the
elevator
tube, shielding requirements there would probably be somewhat
relaxed.
> Given the nature of primaries/secondaries, no shielding at all may
be best.

I would have to do the math, but my gut feeling is that heat
dissipiation for an active shield will be the big problem. I can see
you converting the mass of a passive sheild into the mass of a
radiator to get rid of the extra heat created by the active shielding.

This may not be the case for small space ships. But I think even a
standford torus would be too big for active sheilding.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
> Bill,
>
> Yes, there are details that need to be worked out. Lets try a
thought experiment. Imagine a dumbell shaped space station with a huge
Van De Graff generator separating charges with one end + and the other
-. The - end could be sacrificed or perhaps it will contain the
nuclear reactor or political prisoners :-) while everyone else is safe
in the + end.
> If you like this concept, then replace the - end with an electron
gun that shoots electrons a long way away past the + charge. Perhaps
this gun is located at the end of a tether that also provides some
electrical thrust? Think about it.
>
> Tom
> From: bill t
> To: spacesettlers@egroups.com
> Sent: Tuesday, December 19, 2000 5:17 PM
> Subject: [spacesettlers] Active Sheilding
>
> The main problem with Active Shielding is the polarity of the
field.
> Since the radiation leaving the sun is positive a positive field
will
> repel the particles, but at the same time it will accelerate every
> electron in the vincinity of the habitat towards it. The resulting
> shower on the hull of the habitat will produce enough X-Rays to
kill
> anyone inside.
>
> You can arrange a magnetic field to deflect the electrons, but I'm
> wondering what the weight of the material, and the power
utilization
> is. All the power is heat that has to be radiated away. This means
> more radiators.
>
> How much real savings in weight is there, remembering that the
passive
> sheild will be waste material from industrial processes in space,
and
> the active sheilding material will probably be sent up from earth.
>
> Just a Thought,
>
> Bill
>
> --- In spacesettlers@egroups.com, "Combs, Mike"
> wrote:
> > From: Tom Tucker (Olympia) [mailto:tntucker@c...]
> >
> >
> > From: Dr. Omni
> >
> > It seems that youre a proponent of Active Shielding - the use
of
> magnetic
> > and electric fields to protect your habitat. What are the
> disadvantages that
> > you see with Passive Shielding - simply covering your habitat
with a
> layer
> > of rock (or ice, depending on your location in the Solar System)
a
> few
> > meters thick?
> >
> >
> > Tom - Primarily mass, although inertia will be important.
> >
> >
> > To me, this would be more of an issue for a travelling structure
> than a
> > stationary one.
> >
> >
> > However, I believe that the lowest mass, and hence, largest
volume
> for
> > equal costs, can be achieved using active shielding.
> >
> >
> > If the shielding is made up of slag left over from your ore
refining
> > operation, I don't see it adding a lot to the costs, at least
not
> from a
> > material standpoint. I don't think the construction costs would
be
> as high
> > as for the pressure shell, as I think the construction
requirements
> would
> > not be quite as precise as what's needed for a pressure shell.
> >
> >
> > It would be much better to just turn-up the voltage a bit when
a
> solar
> > flare is due rather than hiding in a shelter IMO.
> >
> >
> > I think the advantage of the 6' thick shield is that you can
just go
> about
> > your buisiness normally during flares.
> >
> >
> > A 4 meter tube/elevator becomes a 12 meter dia tube if shielding
is
> added...
> >
> >
> > I'd question if shielding was even needed for an elevator tube.
The
> 4-6'
> > shielding requirement is for what's safe to live in for the
rest of
> your
> > life. Since one would only spend a short amount of time in the
> elevator
> > tube, shielding requirements there would probably be somewhat
> relaxed.
> > Given the nature of primaries/secondaries, no shielding at all
may

bill t wrote:

> The main problem with Active Shielding...

The main problem with active shielding is that it doesn't
work. Period.

> You can arrange a magnetic field to deflect the electrons, but I'm
> wondering what the weight of the material, and the power utilization
> is. All the power is heat that has to be radiated away. This means
> more radiators.

Radiators aren't a problem. The problem is that people die
from radiation poisoning (10% chance of cancer per 5-10 years
if I remember correctly), caused by cosmic rays. Active shielding
doesn't touch cosmic rays- they're waaaay too high energy. We
can't even produce rays that powerful in our particle
accelerators that are miles across and use whole power
stations to keep them running; active shielding
has absolutely no chance of even deflecting it,
and quite a lot of the particles aren't even charged
anyway.

6 foot of just about anything non radioactive works wonders.

If a lunar mass driver is used that's not ridiculous.

I worked out about $100/ft^2 ballpark. Getting some
near earth asteroids should be cheaper still (some
of them have delta-vs of tens of meters - yes that's
right meters not kilometers, per second.)

Living in asteroids will be much cheaper. Shoring up the
inside of an asteriod you've mined out is pretty simple and cheap
in microgravity.

You get the outside for free pretty much. You don't have to
move anything anywhere, just tie the rubble down, smelt your
aluminium and sling up some big mirrors and put a sign outside
'home sweet home'.

From: Ian Woollard
To: spacesettlers@egroups.com
Sent: Thursday, December 21, 2000 8:57 PM
Subject: Re: [spacesettlers] Active Sheilding

bill t wrote:

> The main problem with Active Shielding...

The main problem with active shielding is that it doesn't
work. Period.

> You can arrange a magnetic field to deflect the electrons, but I'm
> wondering what the weight of the material, and the power utilization
> is. All the power is heat that has to be radiated away. This means
> more radiators.

Radiators aren't a problem. The problem is that people die
from radiation poisoning (10% chance of cancer per 5-10 years
if I remember correctly), caused by cosmic rays. Active shielding
doesn't touch cosmic rays- they're waaaay too high energy. We
can't even produce rays that powerful in our particle
accelerators that are miles across and use whole power
stations to keep them running; active shielding
has absolutely no chance of even deflecting it,
and quite a lot of the particles aren't even charged
anyway.
Tom Tucker - Bill, cosmic rays are nuculi that have been stripped of their electrons which makes them positively charged. Solar flares are a storm of charged particles with the bulk also consisting of ionized nuculi. Both of these types of deadly radiation can be repelled by a positive high voltage charge. Since in space, there is no place for a charge to arc or to drain from via ionization as there is when in an atmosphere, one could perhaps build-up a charge of billions of volts which is comparable to that of cosmic rays and in excess of that found in solar flares. The positive charge would be maintained/generated by the use of an electron gun/accelerator located a few KM from the space craft on the end of a conductive tether. In space, we can generate much higher voltages than we can on earth.
Particle accelerators produce very heavy nuculi at hear the velocitiy of light, but this is not relevant to the electrostatic shielding under discussion here.
Proof of concept has yet to be attempted, but hypothetically, it can be done.

X-Rays from the sun and stars are a much smaller worry and some light shielding would still be needed for these EMF for which active shielding will be ineffective. How much would be needed? Need more data. Perhaps the few CM of steel that a "cruise ship type habitat" would use would be sufficient?

6 foot of just about anything non radioactive works wonders.

If a lunar mass driver is used that's not ridiculous.

I worked out about $100/ft^2 ballpark. Getting some
near earth asteroids should be cheaper still (some
of them have delta-vs of tens of meters - yes that's
right meters not kilometers, per second.)

Living in asteroids will be much cheaper. Shoring up the
inside of an asteriod you've mined out is pretty simple and cheap
in microgravity.

You get the outside for free pretty much. You don't have to
move anything anywhere, just tie the rubble down, smelt your
aluminium and sling up some big mirrors and put a sign outside
'home sweet home'.

> Just a Thought,
>
> Bill

From:
Ian Woollard
To:
spacesettlers@egroups.com
Sent:
Thursday, December 21, 2000 8:57 PM
Subject:
Re: [spacesettlers] Active Sheilding
bill t wrote:
> The main problem with Active Shielding...
The main problem with active shielding is that it doesn't
work. Period.
> You can arrange a magnetic field to deflect the electrons, but I'm
> wondering what the weight of the material, and the power utilization
> is. All the power is heat that has to be radiated away. This means
> more radiators.
Radiators aren't a problem. The problem is that people die
from radiation poisoning (10% chance of cancer per 5-10 years
if I remember correctly), caused by cosmic rays. Active shielding
doesn't touch cosmic rays- they're waaaay too high energy. We
can't even produce rays that powerful in our particle
accelerators that are miles across and use whole power
stations to keep them running; active shielding
has absolutely no chance of even deflecting it,
and quite a lot of the particles aren't even charged
anyway.
Tom Tucker - Bill, cosmic rays are nuculi that have been stripped of their electrons which makes them positively charged. Solar flares are a storm of charged particles with the bulk also consisting of ionized nuculi. Both of these types of deadly radiation can be repelled by a positive high voltage charge. Since in space, there is no place for a charge to arc or to drain from via ionization as there is when in an atmosphere, one could perhaps build-up a charge of billions of volts which is comparable to that of cosmic rays and in excess of that found in solar flares. The positive charge would be maintained/generated by the use of an electron gun/accelerator located a few KM from the space craft on the end of a conductive tether. In space, we can generate much higher voltages than we can on earth.
Particle accelerators produce very heavy nuculi at hear the velocitiy of light, but this is not relevant to the electrostatic shielding under discussion here.
Proof of concept has yet to be attempted, but hypothetically, it can be done.

X-Rays from the sun and stars are a much smaller worry and some light shielding would still be needed for these EMF for which active shielding will be ineffective. How much would be needed? Need more data. Perhaps the few CM of steel that a "cruise ship type habitat" would use would be sufficient?
6 foot of just about anything non radioactive works wonders.
If a lunar mass driver is used that's not ridiculous.
I worked out about $100/ft^2 ballpark. Getting some
near earth asteroids should be cheaper still (some
of them have delta-vs of tens of meters - yes that's
right meters not kilometers, per second.)
Living in asteroids will be much cheaper. Shoring up the
inside of an asteriod you've mined out is pretty simple and cheap
in microgravity.
You get the outside for free pretty much. You don't have to
move anything anywhere, just tie the rubble down, smelt your
aluminium and sling up some big mirrors and put a sign outside
'home sweet home'.

If you are a million volt positive charge, every electron in the
solarsystem will be attracted to you. When they hit the outer shell
they will have a million eV energy each. when a electron hits a metal
(the outer shell) it produces X-Rays. These X-Rays will be directed
towards the interior of the habitat. Thus you will have a constant
X-Ray source inside the habitat.

Finally, for every positive charged nuclei that gets thrown out of the
sun, there is at least one electron that has been dissaciated from it.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
>
> From: Ian Woollard
> To: spacesettlers@egroups.com
> Sent: Thursday, December 21, 2000 8:57 PM
> Subject: Re: [spacesettlers] Active Sheilding
>
> bill t wrote:
>
> > The main problem with Active Shielding...
>
> The main problem with active shielding is that it doesn't
> work. Period.
>
> > You can arrange a magnetic field to deflect the electrons, but
I'm
> > wondering what the weight of the material, and the power
utilization
> > is. All the power is heat that has to be radiated away. This
means
> > more radiators.
>
> Radiators aren't a problem. The problem is that people die
> from radiation poisoning (10% chance of cancer per 5-10 years
> if I remember correctly), caused by cosmic rays. Active shielding
> doesn't touch cosmic rays- they're waaaay too high energy. We
> can't even produce rays that powerful in our particle
> accelerators that are miles across and use whole power
> stations to keep them running; active shielding
> has absolutely no chance of even deflecting it,
> and quite a lot of the particles aren't even charged
> anyway.
> Tom Tucker - Bill, cosmic rays are nuculi that have been stripped
of their electrons which makes them positively charged. Solar flares
are a storm of charged particles with the bulk also consisting of
ionized nuculi. Both of these types of deadly radiation can be
repelled by a positive high voltage charge. Since in space, there is
no place for a charge to arc or to drain from via ionization as there
is when in an atmosphere, one could perhaps build-up a charge of
billions of volts which is comparable to that of cosmic rays and in
excess of that found in solar flares. The positive charge would be
maintained/generated by the use of an electron gun/accelerator located
a few KM from the space craft on the end of a conductive tether. In
space, we can generate much higher voltages than we can on earth.
> Particle accelerators produce very heavy nuculi at hear the
velocitiy of light, but this is not relevant to the electrostatic
shielding under discussion here.
> Proof of concept has yet to be attempted, but hypothetically, it
can be done.
>
> X-Rays from the sun and stars are a much smaller worry and some
light shielding would still be needed for these EMF for which active
shielding will be ineffective. How much would be needed? Need more
data. Perhaps the few CM of steel that a "cruise ship type habitat"
would use would be sufficient?

Bill,

So, I take it you now agree that active shielding can be used to at least deal with cosmic rays and positively charged ions from the sun? By the way, we are talking about billions of volts, not millions since I believe that cosmic rays have an energy equivalent to 30 billion EV.

Now, lets proceed with dealing with those pesky electrons. Since they have a relatively low mass and can be compelled to turn at very sharp corners, we can use either an electric or magnetic field to divert them.

>From a distance, a 1km diameter shell appears to be a point charge. Instead of charging the exterior of the colony with the high charge, lets charge instead a spherical wire grid surrounding the colony. Electrons are attracted to the positively charged grid and are neutralized or diverted, and positively charged nuclei are repelled. Only problem remains to maintain the charge and construction.

Cheers,

Tom

From: bill t
To: spacesettlers@egroups.com
Sent: Saturday, December 23, 2000 2:18 PM
Subject: [spacesettlers] Re: Active Sheilding

If you are a million volt positive charge, every electron in the
solarsystem will be attracted to you. When they hit the outer shell
they will have a million eV energy each. when a electron hits a metal
(the outer shell) it produces X-Rays. These X-Rays will be directed
towards the interior of the habitat. Thus you will have a constant
X-Ray source inside the habitat.

Finally, for every positive charged nuclei that gets thrown out of the
sun, there is at least one electron that has been dissaciated from it.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
>
> From: Ian Woollard
> To: spacesettlers@egroups.com
> Sent: Thursday, December 21, 2000 8:57 PM
> Subject: Re: [spacesettlers] Active Sheilding
>
> bill t wrote:
>
> > The main problem with Active Shielding...
>
> The main problem with active shielding is that it doesn't
> work. Period.
>
> > You can arrange a magnetic field to deflect the electrons, but
I'm
> > wondering what the weight of the material, and the power
utilization
> > is. All the power is heat that has to be radiated away. This
means
> > more radiators.
>
> Radiators aren't a problem. The problem is that people die
> from radiation poisoning (10% chance of cancer per 5-10 years
> if I remember correctly), caused by cosmic rays. Active shielding
> doesn't touch cosmic rays- they're waaaay too high energy. We
> can't even produce rays that powerful in our particle
> accelerators that are miles across and use whole power
> stations to keep them running; active shielding
> has absolutely no chance of even deflecting it,
> and quite a lot of the particles aren't even charged
> anyway.
> Tom Tucker - Bill, cosmic rays are nuculi that have been stripped
of their electrons which makes them positively charged. Solar flares
are a storm of charged particles with the bulk also consisting of
ionized nuculi. Both of these types of deadly radiation can be
repelled by a positive high voltage charge. Since in space, there is
no place for a charge to arc or to drain from via ionization as there
is when in an atmosphere, one could perhaps build-up a charge of
billions of volts which is comparable to that of cosmic rays and in
excess of that found in solar flares. The positive charge would be
maintained/generated by the use of an electron gun/accelerator located
a few KM from the space craft on the end of a conductive tether. In
space, we can generate much higher voltages than we can on earth.
> Particle accelerators produce very heavy nuculi at hear the
velocitiy of light, but this is not relevant to the electrostatic
shielding under discussion here.
> Proof of concept has yet to be attempted, but hypothetically, it
can be done.
>
> X-Rays from the sun and stars are a much smaller worry and some
light shielding would still be needed for these EMF for which active
shielding will be ineffective. How much would be needed? Need more
data. Perhaps the few CM of steel that a "cruise ship type habitat"
would use would be sufficient?
>
> 6 foot of just about anything non radioactive works wonders.
>
> If a lunar mass driver is used that's not ridiculous.
>
> I worked out about $100/ft^2 ballpark. Getting some
> near earth asteroids should be cheaper still (some
> of them have delta-vs of tens of meters - yes that's
> right meters not kilometers, per second.)
>
> Living in asteroids will be much cheaper. Shoring up the
> inside of an asteriod you've mined out is pretty simple and cheap
> in microgravity.
>
> You get the outside for free pretty much. You don't have to
> move anything anywhere, just tie the rubble down, smelt your
> aluminium and sling up some big mirrors and put a sign outside
> 'home sweet home'.
>
> > Just a Thought,
> >
> > Bill
>

So, I take it you now agree that active shielding can be used to at least deal with cosmic rays and positively charged ions from the sun? By the way, we are talking about billions of volts, not millions since I believe that cosmic rays have an energy equivalent to 30 billion EV.

Now, lets proceed with dealing with those pesky electrons. Since they have a relatively low mass and can be compelled to turn at very sharp corners, we can use either an electric or magnetic field to divert them.

From a distance, a 1km diameter shell appears to be a point charge. Instead of charging the exterior of the colony with the high charge, lets charge instead a spherical wire grid surrounding the colony. Electrons are attracted to the positively charged grid and are neutralized or diverted, and positively charged nuclei are repelled. Only problem remains to maintain the charge and construction.

Cheers,

Tom

From:
bill t
To:
spacesettlers@egroups.com
Sent:
Saturday, December 23, 2000 2:18 PM
Subject:
[spacesettlers] Re: Active Sheilding
If you are a million volt positive charge, every electron in the
solarsystem will be attracted to you. When they hit the outer shell
they will have a million eV energy each. when a electron hits a metal
(the outer shell) it produces X-Rays. These X-Rays will be directed
towards the interior of the habitat. Thus you will have a constant
X-Ray source inside the habitat.
Finally, for every positive charged nuclei that gets thrown out of the
sun, there is at least one electron that has been dissaciated from it.
Bill
--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
>
> From: Ian Woollard
> To: spacesettlers@egroups.com
> Sent: Thursday, December 21, 2000 8:57 PM
> Subject: Re: [spacesettlers] Active Sheilding

>
> bill t wrote:
>
> > The main problem with Active Shielding...
>
> The main problem with active shielding is that it doesn't
work. Period.
>
> > You can arrange a magnetic field to deflect the electrons, but
I'm
> > wondering what the weight of the material, and the power
utilization
> > is. All the power is heat that has to be radiated away. This
means
> > more radiators.
>
> Radiators aren't a problem. The problem is that people die
> from radiation poisoning (10% chance of cancer per 5-10 years
> if I remember correctly), caused by cosmic rays. Active shielding
> doesn't touch cosmic rays- they're waaaay too high energy. We
> can't even produce rays that powerful in our particle
> accelerators that are miles across and use whole power
> stations to keep them running; active shielding
> has absolutely no chance of even deflecting it,
> and quite a lot of the particles aren't even charged
> anyway.
> Tom Tucker - Bill, cosmic rays are nuculi that have been stripped
of their electrons which makes them positively charged. Solar flares
are a storm of charged particles with the bulk also consisting of
ionized nuculi. Both of these types of deadly radiation can be
repelled by a positive high voltage charge. Since in space, there is
no place for a charge to arc or to drain from via ionization as there
is when in an atmosphere, one could perhaps build-up a charge of
billions of volts which is comparable to that of cosmic rays and in
excess of that found in solar flares. The positive charge would be
maintained/generated by the use of an electron gun/accelerator located
a few KM from the space craft on the end of a conductive tether. In
space, we can generate much higher voltages than we can on earth.
> Particle accelerators produce very heavy nuculi at hear the
velocitiy of light, but this is not relevant to the electrostatic
shielding under discussion here.
Proof of concept has yet to be attempted, but hypothetically, it
can be done.
>
> X-Rays from the sun and stars are a much smaller worry and some
light shielding would still be needed for these EMF for which active
shielding will be ineffective. How much would be needed? Need more
data. Perhaps the few CM of steel that a "cruise ship type habitat"
would use would be sufficient?

Tom Tucker (Olympia) wrote:

> So, I take it you now agree that active shielding can be used to at
> least deal with cosmic rays and positively charged ions from the sun?
> By the way, we are talking about billions of volts, not millions since I
> believe that cosmic rays have an energy equivalent to 30 billion E

How long will it take for 6 foot of electrode to boil off? At
that voltage it's going to be brighter than the sun with plasma
discharge; space vacuum or no space vacuum.

6 foot of any old junk is cheap, simple, reliable. Why mess
with systems that can fail?

Besides, the junk will help to deal with micrometeorites.
Electromagnetic shielding doesn't help.

Mass is going to be cheap in space. Right now its
expensive ONLY because of launch costs.

-Ian

Ian,

Electrodes do not have to "boil off" any more than the electron gun in your TV screen or monitor has to be consumed by normal operation. Electrons leave the surface by the electronics of electron guns which are well known.

The output beam of an electron gun may produce a blue line in space as if a laser were being fired, but may also curve in response to electric and magnetic fields. Should be very colorful, I predict.

Cheers,

Tom
From: Ian Woollard
To: spacesettlers@egroups.com
Sent: Saturday, December 23, 2000 4:24 PM
Subject: Re: [spacesettlers] Re: Active Sheilding

Tom Tucker (Olympia) wrote:

> So, I take it you now agree that active shielding can be used to at
> least deal with cosmic rays and positively charged ions from the sun?
> By the way, we are talking about billions of volts, not millions since I
> believe that cosmic rays have an energy equivalent to 30 billion E

How long will it take for 6 foot of electrode to boil off? At
that voltage it's going to be brighter than the sun with plasma
discharge; space vacuum or no space vacuum.

6 foot of any old junk is cheap, simple, reliable. Why mess
with systems that can fail?

Besides, the junk will help to deal with micrometeorites.
Electromagnetic shielding doesn't help.

Mass is going to be cheap in space. Right now its
expensive ONLY because of launch costs.

-Ian

Electrodes do not have to "boil off" any more than the electron gun in your TV screen or monitor has to be consumed by normal operation. Electrons leave the surface by the electronics of electron guns which are well known.

The output beam of an electron gun may produce a blue line in space as if a laser were being fired, but may also curve in response to electric and magnetic fields. Should be very colorful, I predict.

Cheers,

Tom
From:
Ian Woollard
To:
spacesettlers@egroups.com
Sent:
Saturday, December 23, 2000 4:24 PM
Subject:
Re: [spacesettlers] Re: Active Sheilding
Tom Tucker (Olympia) wrote:
> So, I take it you now agree that active shielding can be used to at
> least deal with cosmic rays and positively charged ions from the sun?
> By the way, we are talking about billions of volts, not millions since I
> believe that cosmic rays have an energy equivalent to 30 billion E
How long will it take for 6 foot of electrode to boil off? At
that voltage it's going to be brighter than the sun with plasma
discharge; space vacuum or no space vacuum.
6 foot of any old junk is cheap, simple, reliable. Why mess
with systems that can fail?
Besides, the junk will help to deal with micrometeorites.
Electromagnetic shielding doesn't help.
Mass is going to be cheap in space. Right now its
expensive ONLY because of launch costs.
-Ian

Tom Tucker (Olympia) wrote:

> Ian,
>
> Electrodes do not have to "boil off" any more than the electron gun in
> your TV screen or monitor has to be consumed by normal operation.
> Electrons leave the surface by the electronics of electron guns which
> are well known.

Electron guns are gradually destroyed by normal operation.
That's one of the reasons TV pictures get less sharp with age-
the shape of the gun changes and eventually fails. And that's
only ~10,000 volts. Still, they run at higher temperature
and that makes a difference somewhat.

OK. I did a web search. It's a bit more practical than I
thought. But there are many difficulties.

Check out: http://www.islandone.org/Settlements/MagShield.html
for an article by someone who describes a possible system.
It looks like a combination of passive, magnetic and electric
shielding involving superconducting cables would be required.

Ian,

Good reference below! I recommend it for everyone interested in shielding.

Tom
From: Ian Woollard
To: spacesettlers@egroups.com
Sent: Saturday, December 23, 2000 7:06 PM
Subject: Re: [spacesettlers] Re: Active Sheilding

Tom Tucker (Olympia) wrote:

> Ian,
>
> Electrodes do not have to "boil off" any more than the electron gun in
> your TV screen or monitor has to be consumed by normal operation.
> Electrons leave the surface by the electronics of electron guns which
> are well known.

Electron guns are gradually destroyed by normal operation.
That's one of the reasons TV pictures get less sharp with age-
the shape of the gun changes and eventually fails. And that's
only ~10,000 volts. Still, they run at higher temperature
and that makes a difference somewhat.

Tom - Yes, but metal that is ablated can be easily allowed for. Wear should be minor.

What we need now is funding for an advanced engineering analysis for both active and passive shielding, and then some experiments in space on the ISS.

Cheers,

Tom

OK. I did a web search. It's a bit more practical than I
thought. But there are many difficulties.

Check out: http://www.islandone.org/Settlements/MagShield.html
for an article by someone who describes a possible system.
It looks like a combination of passive, magnetic and electric
shielding involving superconducting cables would be required.

> Tom

Good reference below! I recommend it for everyone interested in shielding.

Tom
From:
Ian Woollard
To:
spacesettlers@egroups.com
Sent:
Saturday, December 23, 2000 7:06 PM
Subject:
Re: [spacesettlers] Re: Active Sheilding
Tom Tucker (Olympia) wrote:
> Ian,
>
> Electrodes do not have to "boil off" any more than the electron gun in
> your TV screen or monitor has to be consumed by normal operation.
> Electrons leave the surface by the electronics of electron guns which
> are well known.
Electron guns are gradually destroyed by normal operation.
That's one of the reasons TV pictures get less sharp with age-
the shape of the gun changes and eventually fails. And that's
only ~10,000 volts. Still, they run at higher temperature
and that makes a difference somewhat.
Tom - Yes, but metal that is ablated can be easily allowed for. Wear should be minor.

What we need now is funding for an advanced engineering analysis for both active and passive shielding, and then some experiments in space on the ISS.

Cheers,

Tom
OK. I did a web search. It's a bit more practical than I
thought. But there are many difficulties.
Check out:
http://www.islandone.org/Settlements/MagShield.html
for an article by someone who describes a possible system.
It looks like a combination of passive, magnetic and electric
shielding involving superconducting cables would be required.

You still have the problem of the X-Ray bath caused by all the
electrons hitting the metal grid.

To do it properly you need a magnetic field to divert the electrons
from the grid. Once you have that the billions of volts you will have
to be dissappiate all that energy that gets converted to heat. So we
are again at the heat dissapiation problem.

Anyway, there is a whole class of neutral particles that will be
totally unaffected by electromagnetic shields that could easily kill
everyone.

I'm still into the passive shields camp. It is a low maintanence
solution.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
> Bill,
>
> So, I take it you now agree that active shielding can be used to at
least deal with cosmic rays and positively charged ions from the sun?
By the way, we are talking about billions of volts, not millions since
I believe that cosmic rays have an energy equivalent to 30 billion EV.
>
> Now, lets proceed with dealing with those pesky electrons. Since
they have a relatively low mass and can be compelled to turn at very
sharp corners, we can use either an electric or magnetic field to
divert them.
>
> From a distance, a 1km diameter shell appears to be a point
charge. Instead of charging the exterior of the colony with the high
charge, lets charge instead a spherical wire grid surrounding the
colony. Electrons are attracted to the positively charged grid and
are neutralized or diverted, and positively charged nuclei are
repelled. Only problem remains to maintain the charge and
construction.
>
> Cheers,
>
> Tom
>
> From: bill t
> To: spacesettlers@egroups.com
> Sent: Saturday, December 23, 2000 2:18 PM
> Subject: [spacesettlers] Re: Active Sheilding
>
> If you are a million volt positive charge, every electron in the
> solarsystem will be attracted to you. When they hit the outer
shell
> they will have a million eV energy each. when a electron hits a
metal
> (the outer shell) it produces X-Rays. These X-Rays will be
directed
> towards the interior of the habitat. Thus you will have a constant
> X-Ray source inside the habitat.
>
> Finally, for every positive charged nuclei that gets thrown out of
the
> sun, there is at least one electron that has been dissaciated from
it.
>
> Bill
>
> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> wrote:
> >
> > From: Ian Woollard
> > To: spacesettlers@egroups.com
> > Sent: Thursday, December 21, 2000 8:57 PM
> > Subject: Re: [spacesettlers] Active Sheilding
> >
> >
> > bill t wrote:
> >
> > > The main problem with Active Shielding...
> >
> > The main problem with active shielding is that it doesn't
> > work. Period.
> >
> > > You can arrange a magnetic field to deflect the electrons,
but
> I'm
> > > wondering what the weight of the material, and the power
> utilization
> > > is. All the power is heat that has to be radiated away. This
> means
> > > more radiators.
> >
> > Radiators aren't a problem. The problem is that people die
> > from radiation poisoning (10% chance of cancer per 5-10 years
> > if I remember correctly), caused by cosmic rays. Active
shielding
> > doesn't touch cosmic rays- they're waaaay too high energy. We
> > can't even produce rays that powerful in our particle
> > accelerators that are miles across and use whole power
> > stations to keep them running; active shielding
> > has absolutely no chance of even deflecting it,
> > and quite a lot of the particles aren't even charged
> > anyway.
> > Tom Tucker - Bill, cosmic rays are nuculi that have been
stripped
> of their electrons which makes them positively charged. Solar
flares
> are a storm of charged particles with the bulk also consisting of
> ionized nuculi. Both of these types of deadly radiation can be
> repelled by a positive high voltage charge. Since in space, there
is
> no place for a charge to arc or to drain from via ionization as
there
> is when in an atmosphere, one could perhaps build-up a charge of
> billions of volts which is comparable to that of cosmic rays and
in
> excess of that found in solar flares. The positive charge would
be
> maintained/generated by the use of an electron gun/accelerator
located
> a few KM from the space craft on the end of a conductive tether.
In
> space, we can generate much higher voltages than we can on earth.
> > Particle accelerators produce very heavy nuculi at hear the
> velocitiy of light, but this is not relevant to the electrostatic
> shielding under discussion here.
> > Proof of concept has yet to be attempted, but hypothetically,
it
> can be done.
> >
> > X-Rays from the sun and stars are a much smaller worry and
some
> light shielding would still be needed for these EMF for which
active
> shielding will be ineffective. How much would be needed? Need more
> data. Perhaps the few CM of steel that a "cruise ship type
habitat"
> would use would be sufficient?
> >
> > 6 foot of just about anything non radioactive works wonders.
> >
> > If a lunar mass driver is used that's not ridiculous.
> >
> > I worked out about $100/ft^2 ballpark. Getting some
> > near earth asteroids should be cheaper still (some
> > of them have delta-vs of tens of meters - yes that's
> > right meters not kilometers, per second.)
> >
> > Living in asteroids will be much cheaper. Shoring up the
> > inside of an asteriod you've mined out is pretty simple and
cheap

Bill,

Response below:
From: bill t
To: spacesettlers@egroups.com
Sent: Sunday, December 24, 2000 1:55 PM
Subject: [spacesettlers] Re: Active Sheilding

You still have the problem of the X-Ray bath caused by all the
electrons hitting the metal grid.

Tom - But if the grid is a KM away, the reduction per inverse square law will be substantial. Modest shielding will still be necessary, and I am not arguing against passive shielding, but only that active shielding should be kept on the table and studied.

To do it properly you need a magnetic field to divert the electrons
from the grid. Once you have that the billions of volts you will have
to be dissappiate all that energy that gets converted to heat. So we
are again at the heat dissapiation problem.

Tom - This would require further analysis.

Anyway, there is a whole class of neutral particles that will be
totally unaffected by electromagnetic shields that could easily kill
everyone.

Tom - The only neutral particles I know of are neutrons, and they will have decayed long before arriving on site. Naturally, X and gamma rays must be shielded passively.

I'm still into the passive shields camp. It is a low maintanence
solution.

Bill

--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
wrote:
> Bill,
>
> So, I take it you now agree that active shielding can be used to at
least deal with cosmic rays and positively charged ions from the sun?
By the way, we are talking about billions of volts, not millions since
I believe that cosmic rays have an energy equivalent to 30 billion EV.
>
> Now, lets proceed with dealing with those pesky electrons. Since
they have a relatively low mass and can be compelled to turn at very
sharp corners, we can use either an electric or magnetic field to
divert them.
>
> From a distance, a 1km diameter shell appears to be a point
charge. Instead of charging the exterior of the colony with the high
charge, lets charge instead a spherical wire grid surrounding the
colony. Electrons are attracted to the positively charged grid and
are neutralized or diverted, and positively charged nuclei are
repelled. Only problem remains to maintain the charge and
construction.
>
> Cheers,
>
> Tom
>
> From: bill t
> To: spacesettlers@egroups.com
> Sent: Saturday, December 23, 2000 2:18 PM
> Subject: [spacesettlers] Re: Active Sheilding
>
> If you are a million volt positive charge, every electron in the
> solarsystem will be attracted to you. When they hit the outer
shell
> they will have a million eV energy each. when a electron hits a
metal
> (the outer shell) it produces X-Rays. These X-Rays will be
directed
> towards the interior of the habitat. Thus you will have a constant
> X-Ray source inside the habitat.
>
> Finally, for every positive charged nuclei that gets thrown out of
the
> sun, there is at least one electron that has been dissaciated from
it.
>
> Bill
>
> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> wrote:
> >
> > From: Ian Woollard
> > To: spacesettlers@egroups.com
> > Sent: Thursday, December 21, 2000 8:57 PM
> > Subject: Re: [spacesettlers] Active Sheilding
> >
> >
> > bill t wrote:
> >
> > > The main problem with Active Shielding...
> >
> > The main problem with active shielding is that it doesn't
> > work. Period.
> >
> > > You can arrange a magnetic field to deflect the electrons,
but
> I'm
> > > wondering what the weight of the material, and the power
> utilization
> > > is. All the power is heat that has to be radiated away. This
> means
> > > more radiators.
> >
> > Radiators aren't a problem. The problem is that people die
> > from radiation poisoning (10% chance of cancer per 5-10 years
> > if I remember correctly), caused by cosmic rays. Active
shielding
> > doesn't touch cosmic rays- they're waaaay too high energy. We
> > can't even produce rays that powerful in our particle
> > accelerators that are miles across and use whole power
> > stations to keep them running; active shielding
> > has absolutely no chance of even deflecting it,
> > and quite a lot of the particles aren't even charged
> > anyway.
> > Tom Tucker - Bill, cosmic rays are nuculi that have been
stripped
> of their electrons which makes them positively charged. Solar
flares
> are a storm of charged particles with the bulk also consisting of
> ionized nuculi. Both of these types of deadly radiation can be
> repelled by a positive high voltage charge. Since in space, there
is
> no place for a charge to arc or to drain from via ionization as
there
> is when in an atmosphere, one could perhaps build-up a charge of
> billions of volts which is comparable to that of cosmic rays and
in
> excess of that found in solar flares. The positive charge would
be
> maintained/generated by the use of an electron gun/accelerator
located
> a few KM from the space craft on the end of a conductive tether.
In
> space, we can generate much higher voltages than we can on earth.
> > Particle accelerators produce very heavy nuculi at hear the
> velocitiy of light, but this is not relevant to the electrostatic
> shielding under discussion here.
> > Proof of concept has yet to be attempted, but hypothetically,
it
> can be done.
> >
> > X-Rays from the sun and stars are a much smaller worry and
some
> light shielding would still be needed for these EMF for which
active
> shielding will be ineffective. How much would be needed? Need more
> data. Perhaps the few CM of steel that a "cruise ship type
habitat"
> would use would be sufficient?
> >
> > 6 foot of just about anything non radioactive works wonders.
> >
> > If a lunar mass driver is used that's not ridiculous.
> >
> > I worked out about $100/ft^2 ballpark. Getting some
> > near earth asteroids should be cheaper still (some
> > of them have delta-vs of tens of meters - yes that's
> > right meters not kilometers, per second.)
> >
> > Living in asteroids will be much cheaper. Shoring up the
> > inside of an asteriod you've mined out is pretty simple and
cheap
> > in microgravity.
> >
> > You get the outside for free pretty much. You don't have to
> > move anything anywhere, just tie the rubble down, smelt your
> > aluminium and sling up some big mirrors and put a sign outside
> > 'home sweet home'.
> >
> > > Just a Thought,
> > >
> > > Bill
> >
> >
> >
> >
> >
>

Response below:
From:
bill t
To:
spacesettlers@egroups.com
Sent:
Sunday, December 24, 2000 1:55 PM
Subject:
[spacesettlers] Re: Active Sheilding
You still have the problem of the X-Ray bath caused by all the
electrons hitting the metal grid.
Tom - But if the grid is a KM away, the reduction per inverse square law will be substantial. Modest shielding will still be necessary, and I am not arguing against passive shielding, but only that active shielding should be kept on the table and studied.
To do it properly you need a magnetic field to divert the electrons
from the grid. Once you have that the billions of volts you will have
to be dissappiate all that energy that gets converted to heat. So we
are again at the heat dissapiation problem.
Tom - This would require further analysis.
Anyway, there is a whole class of neutral particles that will be
totally unaffected by electromagnetic shields that could easily kill
everyone.

Tom - The only neutral particles I know of are neutrons, and they will have decayed long before arriving on site. Naturally, X and gamma rays must be shielded passively.
I'm still into the passive shields camp. It is a low maintanence
solution.
Bill
--- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
tntucker@c...> wrote:
> Bill,
>
> So, I take it you now agree that active shielding can be used to at
least deal with cosmic rays and positively charged ions from the sun?
By the way, we are talking about billions of volts, not millions since
I believe that cosmic rays have an energy equivalent to 30 billion EV.
>
> Now, lets proceed with dealing with those pesky electrons. Since
they have a relatively low mass and can be compelled to turn at very
sharp corners, we can use either an electric or magnetic field to
divert them.
>
> From a distance, a 1km diameter shell appears to be a point
charge. Instead of charging the exterior of the colony with the high
charge, lets charge instead a spherical wire grid surrounding the
colony. Electrons are attracted to the positively charged grid and
are neutralized or diverted, and positively charged nuclei are
repelled. Only problem remains to maintain the charge and
construction.
>
> Cheers,
>
> Tom
>
> ----- Original Message -----
> From: bill t
> To: spacesettlers@egroups.com
> Sent: Saturday, December 23, 2000 2:18 PM
> Subject: [spacesettlers] Re: Active Sheilding
>
> If you are a million volt positive charge, every electron in the
> solarsystem will be attracted to you. When they hit the outer
shell
> they will have a million eV energy each. when a electron hits a
metal
> (the outer shell) it produces X-Rays. These X-Rays will be
directed
> towards the interior of the habitat. Thus you will have a constant
> X-Ray source inside the habitat.
>
> Finally, for every positive charged nuclei that gets thrown out of
the
> sun, there is at least one electron that has been dissaciated from
it.
>
> Bill
>
> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
>
> >
> > ----- Original Message -----
> > From: Ian Woollard
> > To: spacesettlers@egroups.com
> > Sent: Thursday, December 21, 2000 8:57 PM
> > Subject: Re: [spacesettlers] Active Sheilding
> >
> >
> > bill t wrote:
> >
> > > The main problem with Active Shielding...
> >
> > The main problem with active shielding is that it doesn't
> > work. Period.
> >
> > > You can arrange a magnetic field to deflect the electrons,
but
> I'm
> > > wondering what the weight of the material, and the power
> utilization
> > > is. All the power is heat that has to be radiated away. This
> means
> > > more radiators.
> >
> > Radiators aren't a problem. The problem is that people die
> > from radiation poisoning (10% chance of cancer per 5-10 years
> > if I remember correctly), caused by cosmic rays. Active
shielding
> > doesn't touch cosmic rays- they're waaaay too high energy. We
> can't even produce rays that powerful in our particle
> > accelerators that are miles across and use whole power
> > stations to keep them running; active shielding
> > has absolutely no chance of even deflecting it,
> > and quite a lot of the particles aren't even charged
> > anyway.
> > Tom Tucker - Bill, cosmic rays are nuculi that have been
stripped
of their electrons which makes them positively charged. Solar
flares
> are a storm of charged particles with the bulk also consisting of
> ionized nuculi. Both of these types of deadly radiation can be
> repelled by a positive high voltage charge. Since in space, there
is
> no place for a charge to arc or to drain from via ionization as
there
> is when in an atmosphere, one could perhaps build-up a charge of
> billions of volts which is comparable to that of cosmic rays and
in
> excess of that found in solar flares. The positive charge would
be
> maintained/generated by the use of an electron gun/accelerator
located
> a few KM from the space craft on the end of a conductive tether.
In
> space, we can generate much higher voltages than we can on earth.
> > Particle accelerators produce very heavy nuculi at hear the
> velocitiy of light, but this is not relevant to the electrostatic
> shielding under discussion here.
> > Proof of concept has yet to be attempted, but hypothetically,
it
> can be done.
> >
> > X-Rays from the sun and stars are a much smaller worry and
some
> light shielding would still be needed for these EMF for which
active
> shielding will be ineffective. How much would be needed? Need more
> data. Perhaps the few CM of steel that a "cruise ship type
habitat"
> would use would be sufficient?
> >
> > 6 foot of just about anything non radioactive works wonders.
> >
> > If a lunar mass driver is used that's not ridiculous.
>
> > I worked out about $100/ft^2 ballpark. Getting some
> > near earth asteroids should be cheaper still (some
> > of them have delta-vs of tens of meters - yes that's
> > right meters not kilometers, per second.)
> >
> > Living in asteroids will be much cheaper. Shoring up the
> > inside of an asteriod you've mined out is pretty simple and
cheap

>
> You still have the problem of the X-Ray bath caused by all the
> electrons hitting the metal grid.
>
> Tom - But if the grid is a KM away, the reduction per inverse
square law will be substantial. Modest shielding will still be
necessary, and I am not arguing against passive shielding, but only
that active shielding should be kept on the table and studied.
>

Actually the X-Rays would increase in radiation. The inverse square
law works for a point source radiating energy away. This is a sphere
radiating energy towards the a point.

In reality the sphere would end up being a grey box with a radiation
level in it porportional to T^4. The real question is what would T end
up at.

> To do it properly you need a magnetic field to divert the
electrons
> from the grid. Once you have that the billions of volts you will
have
> to be dissappiate all that energy that gets converted to heat. So
we
> are again at the heat dissapiation problem.
>
> Tom - This would require further analysis.
>
I don't discount active shielding, but I don't think it would be
feasible for anything other than the smallest vessels.

> Anyway, there is a whole class of neutral particles that will be
> totally unaffected by electromagnetic shields that could easily
kill
> everyone.
>
> Tom - The only neutral particles I know of are neutrons, and they
will have decayed long before arriving on site. Naturally, X and
gamma rays must be shielded passively.
>
Actaully any charged particle leaving the sun could pick up all the
electrons it needs to neutralize, and still be travelling at 3/4 of
the speed of light.

> I'm still into the passive shields camp. It is a low maintanence
> solution.
>
> Bill
>
> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> wrote:
> > Bill,
> >
> > So, I take it you now agree that active shielding can be used to
at
> least deal with cosmic rays and positively charged ions from the
sun?
> By the way, we are talking about billions of volts, not millions
since
> I believe that cosmic rays have an energy equivalent to 30 billion
EV.
> >
> > Now, lets proceed with dealing with those pesky electrons.
Since
> they have a relatively low mass and can be compelled to turn at
very
> sharp corners, we can use either an electric or magnetic field to
> divert them.
> >
> > From a distance, a 1km diameter shell appears to be a point
> charge. Instead of charging the exterior of the colony with the
high
> charge, lets charge instead a spherical wire grid surrounding the
> colony. Electrons are attracted to the positively charged grid
and
> are neutralized or diverted, and positively charged nuclei are
> repelled. Only problem remains to maintain the charge and
> construction.
> >
> > Cheers,
> >
> > Tom
> >
> >
> > From: bill t
> > To: spacesettlers@egroups.com
> > Sent: Saturday, December 23, 2000 2:18 PM
> > Subject: [spacesettlers] Re: Active Sheilding
> >
> >
> >
> >
> > If you are a million volt positive charge, every electron in
the
> > solarsystem will be attracted to you. When they hit the outer
> shell
> > they will have a million eV energy each. when a electron hits
a
> metal
> > (the outer shell) it produces X-Rays. These X-Rays will be
> directed
> > towards the interior of the habitat. Thus you will have a
constant
> > X-Ray source inside the habitat.
> >
> > Finally, for every positive charged nuclei that gets thrown
out of
> the
> > sun, there is at least one electron that has been dissaciated
from
> it.
> >
> > Bill
> >
> > --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> > wrote:
> > >
> > > From: Ian Woollard
> > > To: spacesettlers@egroups.com
> > > Sent: Thursday, December 21, 2000 8:57 PM
> > > Subject: Re: [spacesettlers] Active Sheilding
> > >
> > >
> > > bill t wrote:
> > >
> > > > The main problem with Active Shielding...
> > >
> > > The main problem with active shielding is that it doesn't
> > > work. Period.
> > >
> > > > You can arrange a magnetic field to deflect the
electrons,
> but
> > I'm
> > > > wondering what the weight of the material, and the power
> > utilization
> > > > is. All the power is heat that has to be radiated away.
This
> > means
> > > > more radiators.
> > >
> > > Radiators aren't a problem. The problem is that people die
> > > from radiation poisoning (10% chance of cancer per 5-10
years
> > > if I remember correctly), caused by cosmic rays. Active
> shielding
> > > doesn't touch cosmic rays- they're waaaay too high energy.
We
> > > can't even produce rays that powerful in our particle
> > > accelerators that are miles across and use whole power
> > > stations to keep them running; active shielding
> > > has absolutely no chance of even deflecting it,
> > > and quite a lot of the particles aren't even charged
> > > anyway.
> > > Tom Tucker - Bill, cosmic rays are nuculi that have been
> stripped
> > of their electrons which makes them positively charged. Solar
> flares
> > are a storm of charged particles with the bulk also consisting
of
> > ionized nuculi. Both of these types of deadly radiation can
be
> > repelled by a positive high voltage charge. Since in space,
there
> is
> > no place for a charge to arc or to drain from via ionization
as
> there
> > is when in an atmosphere, one could perhaps build-up a charge
of
> > billions of volts which is comparable to that of cosmic rays
and
> in
> > excess of that found in solar flares. The positive charge
would
> be
> > maintained/generated by the use of an electron gun/accelerator
> located
> > a few KM from the space craft on the end of a conductive
tether.
> In
> > space, we can generate much higher voltages than we can on
earth.
> > > Particle accelerators produce very heavy nuculi at hear
the
> > velocitiy of light, but this is not relevant to the
electrostatic
> > shielding under discussion here.
> > > Proof of concept has yet to be attempted, but
hypothetically,
> it
> > can be done.
> > >
> > > X-Rays from the sun and stars are a much smaller worry and
> some
> > light shielding would still be needed for these EMF for which
> active
> > shielding will be ineffective. How much would be needed? Need
more
> > data. Perhaps the few CM of steel that a "cruise ship type
> habitat"
> > would use would be sufficient?
> > >
> > > 6 foot of just about anything non radioactive works
wonders.
> > >
> > > If a lunar mass driver is used that's not ridiculous.
> > >
> > > I worked out about $100/ft^2 ballpark. Getting some
> > > near earth asteroids should be cheaper still (some
> > > of them have delta-vs of tens of meters - yes that's
> > > right meters not kilometers, per second.)
> > >
> > > Living in asteroids will be much cheaper. Shoring up the
> > > inside of an asteriod you've mined out is pretty simple
and
> cheap
> > > in microgravity.
> > >
> > > You get the outside for free pretty much. You don't have
to
> > > move anything anywhere, just tie the rubble down, smelt
your
> > > aluminium and sling up some big mirrors and put a sign
outside

From: bill t
To: spacesettlers@egroups.com
Sent: Monday, December 25, 2000 9:39 AM
Subject: [spacesettlers] Re: Active Sheilding

>
> You still have the problem of the X-Ray bath caused by all the
> electrons hitting the metal grid.
>
> Tom - But if the grid is a KM away, the reduction per inverse
square law will be substantial. Modest shielding will still be
necessary, and I am not arguing against passive shielding, but only
that active shielding should be kept on the table and studied.
>

Actually the X-Rays would increase in radiation. The inverse square
law works for a point source radiating energy away. This is a sphere
radiating energy towards the a point.

Tom - The X Rays would each be released in a sphere from the point of impact so the radiation is spread in all directions with only a small fraction covering the space colony. The gray box analogy is only partially true since the radiation would be coming from all directions.
The gird concept is only one of many that an engineering team should consider if there is ever funding to proceed in this arena.
Another concept would be to capture the energy of the incoming electrons using a magnetic trap. Setup a bar magnetic shape magnetic field using super conducting coils. The electrons would be attracted to the magnetic pole where they could be diverted and trapped by a cleavely designed magnetic reversal field that would then allow them to be drawn off for storage in a capacitor-like storage device. This alternative has the potential to eliminate the emission of X-Rays altogether and to provide a source of electrons for other uses. This facility could be electrically isolated from the space colony.

In reality the sphere would end up being a grey box with a radiation
level in it porportional to T^4. The real question is what would T end
up at.

> To do it properly you need a magnetic field to divert the
electrons
> from the grid. Once you have that the billions of volts you will
have
> to be dissappiate all that energy that gets converted to heat. So
we
> are again at the heat dissapiation problem.
>
> Tom - This would require further analysis.
>
I don't discount active shielding, but I don't think it would be
feasible for anything other than the smallest vessels.

> Anyway, there is a whole class of neutral particles that will be
> totally unaffected by electromagnetic shields that could easily
kill
> everyone.
>
> Tom - The only neutral particles I know of are neutrons, and they
will have decayed long before arriving on site. Naturally, X and
gamma rays must be shielded passively.
>
Actaully any charged particle leaving the sun could pick up all the
electrons it needs to neutralize, and still be travelling at 3/4 of
the speed of light.

> I'm still into the passive shields camp. It is a low maintanence
> solution.
>
> Bill
>
Tom - OK. To see the advantages of active shielding, you need to consider that the millions of tons of dead (i.e. not tensile strength) material that must be managed when changing orbit, construction, etc. will be very costly to induce a delta V to. Active shielding has the potential to cut the total mass of a colony by 50% or more depending upon design options. The concept that I am considering involves the living space modules moving along the radius of rotation to compensate for increased RPM when launching space craft. Moving from 1G distance to 0.2 G distance while the RPMs are increased to produce 10G at the launching bay will be difficult enough if the modules are of steel let alone if they also have 3 meters of rock/dust between their outer walls.

Cheers,

Tom

> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> wrote:
> > Bill,
> >
> > So, I take it you now agree that active shielding can be used to
at
> least deal with cosmic rays and positively charged ions from the
sun?
> By the way, we are talking about billions of volts, not millions
since
> I believe that cosmic rays have an energy equivalent to 30 billion
EV.
> >
> > Now, lets proceed with dealing with those pesky electrons.
Since
> they have a relatively low mass and can be compelled to turn at
very
> sharp corners, we can use either an electric or magnetic field to
> divert them.
> >
> > From a distance, a 1km diameter shell appears to be a point
> charge. Instead of charging the exterior of the colony with the
high
> charge, lets charge instead a spherical wire grid surrounding the
> colony. Electrons are attracted to the positively charged grid
and
> are neutralized or diverted, and positively charged nuclei are
> repelled. Only problem remains to maintain the charge and
> construction.
> >
> > Cheers,
> >
> > Tom
> >
> >
> > From: bill t
> > To: spacesettlers@egroups.com
> > Sent: Saturday, December 23, 2000 2:18 PM
> > Subject: [spacesettlers] Re: Active Sheilding
> >
> >
> >
> >
> > If you are a million volt positive charge, every electron in
the
> > solarsystem will be attracted to you. When they hit the outer
> shell
> > they will have a million eV energy each. when a electron hits
a
> metal
> > (the outer shell) it produces X-Rays. These X-Rays will be
> directed
> > towards the interior of the habitat. Thus you will have a
constant
> > X-Ray source inside the habitat.
> >
> > Finally, for every positive charged nuclei that gets thrown
out of
> the
> > sun, there is at least one electron that has been dissaciated
from
> it.
> >
> > Bill
> >
> > --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> > wrote:
> > >
> > > From: Ian Woollard
> > > To: spacesettlers@egroups.com
> > > Sent: Thursday, December 21, 2000 8:57 PM
> > > Subject: Re: [spacesettlers] Active Sheilding
> > >
> > >
> > > bill t wrote:
> > >
> > > > The main problem with Active Shielding...
> > >
> > > The main problem with active shielding is that it doesn't
> > > work. Period.
> > >
> > > > You can arrange a magnetic field to deflect the
electrons,
> but
> > I'm
> > > > wondering what the weight of the material, and the power
> > utilization
> > > > is. All the power is heat that has to be radiated away.
This
> > means
> > > > more radiators.
> > >
> > > Radiators aren't a problem. The problem is that people die
> > > from radiation poisoning (10% chance of cancer per 5-10
years
> > > if I remember correctly), caused by cosmic rays. Active
> shielding
> > > doesn't touch cosmic rays- they're waaaay too high energy.
We
> > > can't even produce rays that powerful in our particle
> > > accelerators that are miles across and use whole power
> > > stations to keep them running; active shielding
> > > has absolutely no chance of even deflecting it,
> > > and quite a lot of the particles aren't even charged
> > > anyway.
> > > Tom Tucker - Bill, cosmic rays are nuculi that have been
> stripped
> > of their electrons which makes them positively charged. Solar
> flares
> > are a storm of charged particles with the bulk also consisting
of
> > ionized nuculi. Both of these types of deadly radiation can
be
> > repelled by a positive high voltage charge. Since in space,
there
> is
> > no place for a charge to arc or to drain from via ionization
as
> there
> > is when in an atmosphere, one could perhaps build-up a charge
of
> > billions of volts which is comparable to that of cosmic rays
and
> in
> > excess of that found in solar flares. The positive charge
would
> be
> > maintained/generated by the use of an electron gun/accelerator
> located
> > a few KM from the space craft on the end of a conductive
tether.
> In
> > space, we can generate much higher voltages than we can on
earth.
> > > Particle accelerators produce very heavy nuculi at hear
the
> > velocitiy of light, but this is not relevant to the
electrostatic
> > shielding under discussion here.
> > > Proof of concept has yet to be attempted, but
hypothetically,
> it
> > can be done.
> > >
> > > X-Rays from the sun and stars are a much smaller worry and
> some
> > light shielding would still be needed for these EMF for which
> active
> > shielding will be ineffective. How much would be needed? Need
more
> > data. Perhaps the few CM of steel that a "cruise ship type
> habitat"
> > would use would be sufficient?
> > >
> > > 6 foot of just about anything non radioactive works
wonders.
> > >
> > > If a lunar mass driver is used that's not ridiculous.
> > >
> > > I worked out about $100/ft^2 ballpark. Getting some
> > > near earth asteroids should be cheaper still (some
> > > of them have delta-vs of tens of meters - yes that's
> > > right meters not kilometers, per second.)
> > >
> > > Living in asteroids will be much cheaper. Shoring up the
> > > inside of an asteriod you've mined out is pretty simple
and
> cheap
> > > in microgravity.
> > >
> > > You get the outside for free pretty much. You don't have
to
> > > move anything anywhere, just tie the rubble down, smelt
your
> > > aluminium and sling up some big mirrors and put a sign
outside
> > > 'home sweet home'.
> > >
> > > > Just a Thought,
> > > >
> > > > Bill
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
>

From:
bill t
To:
spacesettlers@egroups.com
Sent:
Monday, December 25, 2000 9:39 AM
Subject:
[spacesettlers] Re: Active Sheilding
>
> You still have the problem of the X-Ray bath caused by all the
> electrons hitting the metal grid.
>
> Tom - But if the grid is a KM away, the reduction per inverse
square law will be substantial. Modest shielding will still be
necessary, and I am not arguing against passive shielding, but only
that active shielding should be kept on the table and studied.
>
Actually the X-Rays would increase in radiation. The inverse square
law works for a point source radiating energy away. This is a sphere
radiating energy towards the a point.
Tom - The X Rays would each be released in a sphere from the point of impact so the radiation is spread in all directions with only a small fraction covering the space colony. The gray box analogy is only partially true since the radiation would be coming from all directions.
The gird concept is only one of many that an engineering team should consider if there is ever funding to proceed in this arena.
Another concept would be to capture the energy of the incoming electrons using a magnetic trap. Setup a bar magnetic shape magnetic field using super conducting coils. The electrons would be attracted to the magnetic pole where they could be diverted and trapped by a cleavely designed magnetic reversal field that would then allow them to be drawn off for storage in a capacitor-like storage device. This alternative has the potential to eliminate the emission of X-Rays altogether and to provide a source of electrons for other uses. This facility could be electrically isolated from the space colony.

In reality the sphere would end up being a grey box with a radiation
level in it porportional to T^4. The real question is what would T end
up at.
> To do it properly you need a magnetic field to divert the
electrons
> from the grid. Once you have that the billions of volts you will
have
> to be dissappiate all that energy that gets converted to heat. So
we
> are again at the heat dissapiation problem.
>
> Tom - This would require further analysis.
>
I don't discount active shielding, but I don't think it would be
feasible for anything other than the smallest vessels.
> Anyway, there is a whole class of neutral particles that will be
> totally unaffected by electromagnetic shields that could easily
kill
> everyone.
>
> Tom - The only neutral particles I know of are neutrons, and they
will have decayed long before arriving on site. Naturally, X and
gamma rays must be shielded passively.
>
Actaully any charged particle leaving the sun could pick up all the
electrons it needs to neutralize, and still be travelling at 3/4 of
the speed of light.
> I'm still into the passive shields camp. It is a low maintanence
> solution.
>
> Bill
>
Tom - OK. To see the advantages of active shielding, you need to consider that the millions of tons of dead (i.e. not tensile strength) material that must be managed when changing orbit, construction, etc. will be very costly to induce a delta V to. Active shielding has the potential to cut the total mass of a colony by 50% or more depending upon design options. The concept that I am considering involves the living space modules moving along the radius of rotation to compensate for increased RPM when launching space craft. Moving from 1G distance to 0.2 G distance while the RPMs are increased to produce 10G at the launching bay will be difficult enough if the modules are of steel let alone if they also have 3 meters of rock/dust between their outer walls.

Cheers,

Tom

> --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
>
> > Bill,
> >
> > So, I take it you now agree that active shielding can be used to
at
> least deal with cosmic rays and positively charged ions from the
sun?
> By the way, we are talking about billions of volts, not millions
since
I believe that cosmic rays have an energy equivalent to 30 billion
EV.
> >
> > Now, lets proceed with dealing with those pesky electrons.
Since
they have a relatively low mass and can be compelled to turn at
very
> sharp corners, we can use either an electric or magnetic field to
> divert them.
> >
> > From a distance, a 1km diameter shell appears to be a point
> charge. Instead of charging the exterior of the colony with the
high
> charge, lets charge instead a spherical wire grid surrounding the
> colony. Electrons are attracted to the positively charged grid
and
> are neutralized or diverted, and positively charged nuclei are
> repelled. Only problem remains to maintain the charge and
> construction.
> >
> > Cheers,
>
> > Tom
> >
> >
> > From: bill t
> > To: spacesettlers@egroups.com
> Sent: Saturday, December 23, 2000 2:18 PM
> > Subject: [spacesettlers] Re: Active Sheilding
> >
> >
>
> >
> > If you are a million volt positive charge, every electron in
the
> > solarsystem will be attracted to you. When they hit the outer
> shell
> > they will have a million eV energy each. when a electron hits
a
> metal
> > (the outer shell) it produces X-Rays. These X-Rays will be
> directed
> > towards the interior of the habitat. Thus you will have a
constant
> > X-Ray source inside the habitat.
> >
> > Finally, for every positive charged nuclei that gets thrown
out of
> the
> > sun, there is at least one electron that has been dissaciated
from
> it.
> >
> > Bill
> >
> > --- In spacesettlers@egroups.com, "Tom Tucker (Olympia)"
> >
> > >
> > > From: Ian Woollard
> > > To: spacesettlers@egroups.com
> > > Sent: Thursday, December 21, 2000 8:57 PM
> > Subject: Re: [spacesettlers] Active Sheilding
> > >
> >
> > > bill t wrote:
> > >
> > > > The main problem with Active Shielding...
> > >
> > > The main problem with active shielding is that it doesn't
> > > work. Period.
> > >
> > > > You can arrange a magnetic field to deflect the
electrons,
> but
> > I'm
> > > wondering what the weight of the material, and the power
> > utilization
> > > > is. All the power is heat that has to be radiated away.
This
> > means
> > > > more radiators.
> > >
> > > Radiators aren't a problem. The problem is that people die
> > > from radiation poisoning (10% chance of cancer per 5-10
years
> > > if I remember correctly), caused by cosmic rays. Active
> shielding
> > > doesn't touch cosmic rays- they're waaaay too high energy.
We
> > > can't even produce rays that powerful in our particle
> > > accelerators that are miles across and use whole power
> > > stations to keep them running; active shielding
> > > has absolutely no chance of even deflecting it,
> > > and quite a lot of the particles aren't even charged
> > > anyway.
> > > Tom Tucker - Bill, cosmic rays are nuculi that have been
> stripped
> of their electrons which makes them positively charged. Solar
> flares
> > are a storm of charged particles with the bulk also consisting
of
> > ionized nuculi. Both of these types of deadly radiation can
be
> > repelled by a positive high voltage charge. Since in space,
there
> is
> > no place for a charge to arc or to drain from via ionization
as
> there
> > is when in an atmosphere, one could perhaps build-up a charge
of
> > billions of volts which is comparable to that of cosmic rays
and
> in
> > excess of that found in solar flares. The positive charge
would
> be
> > maintained/generated by the use of an electron gun/accelerator
> located
> > a few KM from the space craft on the end of a conductive
tether.
> In
> > space, we can generate much higher voltages than we can on
earth.
> > > Particle accelerators produce very heavy nuculi at hear
the
> > velocitiy of light, but this is not relevant to the
electrostatic
> > shielding under discussion here.
> > > Proof of concept has yet to be attempted, but
hypothetically,
> it
> > can be done.
> > >
> > > X-Rays from the sun and stars are a much smaller worry and
> some
> > light shielding would still be needed for these EMF for which
> active
> > shielding will be ineffective. How much would be needed? Need
more
> > data. Perhaps the few CM of steel that a "cruise ship type
> habitat"
> > would use would be sufficient?
> >
> > > 6 foot of just about anything non radioactive works
wonders.
> >
> > > If a lunar mass driver is used that's not ridiculous.
> > >
> > > I worked out about $100/ft^2 ballpark. Getting some
> > > near earth asteroids should be cheaper still (some
> > > of them have delta-vs of tens of meters - yes that's
> > > right meters not kilometers, per second.)
> > >
> > > Living in asteroids will be much cheaper. Shoring up the
> > > inside of an asteriod you've mined out is pretty simple
and
> cheap
> > > in microgravity.
> > >
> > > You get the outside for free pretty much. You don't have
to
> > move anything anywhere, just tie the rubble down, smelt
your
> > > aluminium and sling up some big mirrors and put a sign
outside