William Mook wrote:
On Friday, January 6, 2017 at 6:29:57 PM UTC+13, Fred J. McCall wrote:
William Mook wrote:
On Wednesday, January 4, 2017 at 6:59:50 PM UTC+13, Fred J. McCall wrote:
William Mook wrote:
On Tuesday, January 3, 2017 at 7:34:46 PM UTC+13, Fred J. McCall wrote:
William Mook wrote:
On Tuesday, January 3, 2017 at 12:48:44 PM UTC+13, Fred J. McCall wrote:
JF Mezei wrote:
On 2017-01-02 14:48, Jeff Findley wrote:
Also, I'm sure you'd have to inflate the inner structure to a fairly
high pressure (compared to Mars atmospheric pressure) so it's not
crushed by the weight of the water above it.
Since NASA said it might take 400 days to generate the water to fill it,
I would assume they would pour small amounts of water at a time and it
would freeze rapidly, so the inflated structure would only need to
suipport small amounts of water at any point in time since the rest
would be frozen and become rigid part of structure.
BTW, would CO2 ice provide any filtering for sun's radiation ? This
would be more readily available, but may present challenges to get in
into a dense enough packing to filter radiation out. (on Earth, at one 1
ATM, it is next to impossible, short of extremely cold temperatures to
have it in liquid state).
What magical insulation is supposed to exist to prevent heat from the
inside from melting the structure? Or are you assuming that humans
will live at dry ice temperatures? And CO2 doesn't work very well.
Note that the same 'heat' problem applies to water ice. They talk
about having a CO2 gas layer as 'insulation', but I just don't see
that as having all that much insulating capability.
http://www.lpi.usra.edu/lunar/docume...SA_TP_3079.pdf
http://www.lpi.usra.edu/meetings/nlsc2008/pdf/2028.pdf
25 grams per cm2 provides total dose reduction.
I don't see that number in either of your sources. Where are you
finding it?
In this reference;
http://www.lpi.usra.edu/lunar/docume...SA_TP_3079.pdf
I asked a simple question. It only required a simple answer.
Pointing out a reference is about as simple as it gets.
No, Mook. That's why lawyers hand over warehouses full of **** during
disclosure. It's 'simple' (and obfuscatory).
I gave a single reference not a warehouse. It contained all the information you need to figure out the thickness of materials needed, from sand to water ice to carbon dioxide.
You gave a single reference, flapped your arms like a chicken, and
said "it's in there (somewhere)". You just make yourself look like a
buffoon when you do that.
Propagation data section begins on page 7. Figure 9 shows how slab depth data from a single beam normally incicent to a slab can be used to calculate total reduction of isotropic radiation within a shell.
Symbols and abbreviations are given on page 2 column 2.
Irrelevant to the answer to the question
You must know what the symbols mean in order to read the charts that use them.
You pointing it out is still irrelevant.
Knowing what the symbols mean is important. For example BFO means blood forming organ - which is the bone marrow in humans. The amount of radiation is far less there, when compared to say Skin - so, these details are important in understanding the nature of exposure and what you must do to mitigate it.
You will do anything just to hear yourself natter on, won't you?
are not talking about CO2 as radiation
shielding, which is what was being talked about in the article you
responded to).
The data on table 12 details the impact of CO2 sheilding from the Martian atmosphere. Dry ice varies from 1.2 g/cc to 1.6 g/cc in density. So, its pretty straightforward to figure out the amount needed from this data.
Uh, the last table in the document is Table 8.
Figure 12 genius at the top of page 8.
Oh, I see. You insult ME because YOU don't know the difference
between 'Table' and 'Figure'. I had assumed you could read, even if
you didn't understand it. I'll revise that and just assume you can't
read in future.
Figure 11 on page 8 shows the attenuation of the sum of major flare events recorded in 1989 on the blood forming organ in humans. 25 grams/cm2 of water according to this figure drops 300 REM per year to 5 REM per year which is the limit set by NASA.
You're talking about WATER as shielding, which
was never a question.
Water Ice is the solid form of water in case you didn't know. CO2 gas is the gaseous form of CO2 unless you didn't know. The stopping power of Aluminum, Water, Hydrogen are plotted together to show how atomic weight impacts stopping power on a g/cm2 basis. All the data is there to figure out whatever you need to make use of regolith, liquified or solidified gases, or solidified liquids found in-situ.
The question was about DRY ICE, you nitwit.
CO2 attenuation is given in g/cm2 as well.
Nope.
In addition, even when we were talking about
water we were talking about water ICE, which is less effective than
liquid water (lower density; if you're talking ice thickness, density
is roughly 92% that of liquid water).
Site? I mentioned attenuation in terms of grams/cm2 - that remains virtually the same regardless of whether you're talking gaseous CO2, liquid CO2 or solid CO2, gaseous water vapor, liquid water, or solid water ice.
I assume you mean 'cite'. The thickness required to get a g/cc is
different for ice than for water, you nitwit.
No substantial differences - which is why they put it in terms of g/cm2 not thickness per cm2.
"No substantial differences" in the density of water vs the density of
ice? Yeah, right.
However, let's look at your numbers.
They're not my numbers they're the numbers given in the article.
You put them forward. They're yours.
No, they're the numbers provided by Simonsen and Nealy at the Langley Research Center.
Yes, you put them forward. They're yours.
A shield thickness of 25 g/cm2
looks more like 8 REM to me rather than 5
Well, the authors of the article mention 16 g/cm2 but I guess you didn't see that.
Did you look at the bloody chart, you nitwit?
I did. It's obvious you didn't.
Have you always been an asshat or did you have a stroke at some point?
(and it's still unclear what
you mean by "total dose reduction").
Its described in the article.
However, even assuming 5 REM
annual BFO dose and ignoring that annual dose limits for eyes and skin
are lower, you still have a huge problem.
Ah, here comes the MookSpew...
snip MookSpew
And bear in mind that the career limit assumes a 3% excess risk of
cancer death.
5 REM per year takes 120 years to reach the career limit of 600 REM.
But you're not getting down to 5 REM.
With sufficiently thick walls you do. Recall, 5 REM/yr is the annual dose permitted by radiation workers, 50 REM/year is the limit for astronauts on active duty.
You specified your thickness. Moving the goalposts AGAIN, Mookie?
FLARES down to 5 REM.
Sure if you're looking at Figure 12.
Make sure you are. Do you see ANY of those curves getting down to 5
REM/yr? I don't.
Then you die from GCR.
Only if you're stupid and don't provide sufficient thickness.
As I said, then YOU die from GCR.
Once again we see
Mookie not understanding what he reads.
Hahaha.. you don't understand what is being said, and blame the person who says it. You always do that.
Typical Mookie projection. Rubber/Glue/Waaaa!!!!
So your 'conservative' number might be OK for
exploration missions, but if you plan on living there it's not nearly
good enough.
Nonsense.
Do the math, nitwit.
I have.
Mars surface radiation flux is 30 uSv/hr.
The actual absorbed dose measured by the RAD is 76 mGy/yr at the surface - that's 7.6 REM per year or 8.7 micro-Sieverts per hour. The reality is 29% as intense as you falsely assert here.
http://authors.library.caltech.edu/4...13_FINAL.pd f
Doesn't match other reports of data that Curiosity has provided over
its lifetime. It comes in around an average of 27 uSv/hr.
http://www.space.com/23875-mars-radi...d-mission.html
"RAD's data show that astronauts exploring the Martian surface would
accumulate about 0.64 millisieverts of radiation per day."
The number in your report is also the rate at solar maximum, which
means it's less than half the dose rate at solar minimum (seems
counter intuitive, doesn't it, but GCRs drop during solar maximum and
GCRs are most of what gets to the surface). From the report you cite:
"GCRs are high energy particles (10 MeV/nuc to 10 GeV/nuc) which are
modulated by the heliosphere and anti-correlated with solar activity."
and
"Figure 1 shows the radiation dose rate measured by RAD on the Mars
surface during the first 300 Sols on Mars, near the maximum of Solar
Cycle 24."
So your 8.7 uSv/hr number is the MINIMUM radiation at Mars surface. If
you're talking about safety, you want to use the MAXIMUM (around 27
uSv/hr).
Bored now with your constant misinterpretation of things and insults
when you don't understand...
big snip unread
--
"So many women. So little charm."
-- Donna, to Josh; The West Wing