New Space Settlement image

From: Combs, Mike
To: 'spacesettlers@egroups.com'
Sent: Monday, December 18, 2000 5:52 AM
Subject: RE: [spacesettlers] Re: New Space Settlement image

From: Tom Tucker (Olympia) [mailto:tntucker@...]

5) Gardens must be shielded from cosmic rays and solar wind/flares. The use of high voltages to repel charged particles is recommended.

As it happens, the people will actually be more sensitive to radiation than the plants.

You might want to read T. A. Heppenheimer's "Colonies In Space". He details how in the early days of space settlement studies they looked at a combination of positive charge and magnetic fields for shielding, but eventually decided that the complications were prohibitive and that passive shielding was both simpler and better.

Tom - Yes, I have the book and believe that the design deserves to be left on the table. It is true if you have millions of tons of "dross" as he says on page 162, that shielding makes sense, however, what do you use in the meantime? Also, if your space colony/station is a space machine for launching space ships, shielding may be more difficult than shielding a donut shape. The use of a high voltage for shielding from cosmic rays and solar wind is very appealing to me. It even makes sense to consider it for space ships, especially if the space ships are plasma driven since they would already have the ability to generate very large voltages, especially if it was nuclear powered.
I have yet to see an economic analysis that would justify taking the active shielding option off of the table.

You mentioned asteroid mining, so there should be plenty of leftover slag available for shielding. You also mentioned using your station for momentum transfers. A more-massive station would then be preferable.

Tom - Yes, but we must also be able to move the structural components and this may make very massive components more difficult to manuver. Alloy steel from asteroids is the preferred material along with aluminum and titanium when we can get it.

Regards,
Mike Combs

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From:
Combs, Mike
To:
'spacesettlers@egroups.com'
Sent:
Monday, December 18, 2000 5:52 AM
Subject:
RE: [spacesettlers] Re: New Space Settlement image
From:
Tom Tucker (Olympia) [mailto:tntucker@...]
5) Gardens must be shielded from cosmic rays and solar wind/flares. The use of high voltages to repel charged particles is recommended.

As it happens, the people will actually be more sensitive to radiation than the plants.

You might want to read T. A. Heppenheimer's "Colonies In Space". He details how in the early days of space settlement studies they looked at a combination of positive charge and magnetic fields for shielding, but eventually decided that the complications were prohibitive and that passive shielding was both simpler and better.

Tom - Yes, I have the book and believe that the design deserves to be left on the table. It is true if you have millions of tons of "dross" as he says on page 162, that shielding makes sense, however, what do you use in the meantime? Also, if your space colony/station is a space machine for launching space ships, shielding may be more difficult than shielding a donut shape. The use of a high voltage for shielding from cosmic rays and solar wind is very appealing to me. It even makes sense to consider it for space ships, especially if the space ships are plasma driven since they would already have the ability to generate very large voltages, especially if it was nuclear powered.
I have yet to see an economic analysis that would justify taking the active shielding option off of the table.

You mentioned asteroid mining, so there should be plenty of leftover slag available for shielding. You also mentioned using your station for momentum transfers. A more-massive station would then be preferable.

Tom - Yes, but we must also be able to move the structural components and this may make very massive components more difficult to manuver. Alloy steel from asteroids is the preferred material along with aluminum and titanium when we can get it.

Regards,
Mike Combs