Active Sheilding

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'.