I was reviewing the April 2007 KalpanaOne Orbital Space Settlement
Revised .pdf (Al Globus, et al)and noted that the recommended hull
radiation protection for a LEO settlement (within the Van Allen Belt)
is 10 tons/square meter. This estimate is based on the 10 tons/square
meter of earth atmosphere that we earth bound humans have enjoyed
throughout our evolution. The radiation protection of the settlement
would presumably be provided by lunar regolith.
My question is this: If the cylindrical hull of KalpanaOne were
composed of a series of stacked inflatable water ice filled "donuts" -
probably consisting of several interlocking nested rings of sufficient
depth - covered by the hard cylindrical shell, would this
configuration reduce the mass of the radiation shielding required. I
ask this because I understand that water is one of the most effective
radiation shielding materials known.
I understand that obtaining the massive quantities of water for water
ice shielding would be prolematic. As a thought experiment, though,
I'm wondering if water ice radiation shielding might provide superior
structural strength, radiation shielding and micrometeorite shielding.
Does anyone know how much water ice would provide the equivalent
radiation shielding of 10 tons/square meter of atmosphere?
Chris
On Dec 25, 2007, at 23:20 UTC, Chris Smyth wrote:
> radiation shielding of 10 tons/square meter of atmosphere?
Approximately, 10 tons/square meter. It's pretty much mass that
matters, not what the mass is made of. Low-density mass is slightly
better than high-density mass, since it has a better chance of
absorbing secondaries before they escape out the other side. So, you'd
need slightly more water than atmosphere, and slightly more lead than
you would water. But to a first approximation, it's all just mass.
And BTW, you probably want dirt in your habitat to grow plants in, set
flagpoles in, lay foundations in, etc. It doesn't take more than a
couple meters of dirt to give you all the radiation protection you need
anyway.
Best,
- Joe
Joe Strout
Inspiring Applications, Inc.
http://www.InspiringApps.com
Hi Joe,
since water is a little better at shielding than air,
I'd say 6 to 7 tons per square meter.
Dave Handwerk
--- joe@... wrote:
Hi Joe and Dave,
likely to be a much more valuable commodity than dirt for the
foreseeable future I must (with considerable embarrassment) concede
your point.
On a different note - KalpanaOne is designed for a population of
approximately 3,000. Do you know if an analysis of the CELSS (Closed
Ecological Life Support System) requirements for this size population
has been made? I'm thinking of the general space requirements,
man-hour requirements, infrastructure requirements and energy
requirements.
What comes to mind is the ill-fated Biosphere II experiment wherein
the "biospherians" nearly suffocated due to lack of oxygen, nearly
starved for lack of food, and nearly killed each other for lack of
(compatibility...organization...leadership...?). Any thoughts on this?
Chris
--- In spacesettlers@yahoogroups.com, Dave Handwerk wrote: