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Post by trebor on Apr 8, 2010 16:33:05 GMT -4
'lo people.
I have had a HB recently state that a physicist called John Mauldin claimed that a spacecraft would need 2 metres of water to shield against the Van Allen belt.
They even quoted the source being his book "Prospects for interstellar travel" on page 225/226.
Not having access to a copy and knowing the propensity for many to quote mine like anything; does anyone know exactly what he stated about the VAB in that book?
It certainly seems a bit quote miney to me considering the title.
Cheers,
Trebor
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 8, 2010 16:38:07 GMT -4
I haven't read the book either, but from those who have, Mauldin states that a generational interstellar spacecraft would need a couple meters of shielding to protect the crew from cosmic radiation. He's not talking about a one-hour trip through the Van Allen Radiation Belts.
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Post by trebor on Apr 8, 2010 17:12:30 GMT -4
I haven't read the book either, but from those who have, Mauldin states that a generational interstellar spacecraft would need a couple meters of shielding to protect the crew from cosmic radiation. He's not talking about a one-hour trip through the Van Allen Radiation Belts. That would be way beyond quote mine territory and into flat out lying. :\ It would make sense though, the problems of interstellar travel being so huge that the VABs are trivial by comparison. |
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Post by chew on Apr 8, 2010 18:55:50 GMT -4
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Post by HeadLikeARock (was postbaguk) on Apr 9, 2010 3:28:24 GMT -4
'lo people. I have had a HB recently state that a physicist called John Mauldin claimed that a spacecraft would need 2 metres of water to shield against the Van Allen belt. They even quoted the source being his book "Prospects for interstellar travel" on page 225/226. Not having access to a copy and knowing the propensity for many to quote mine like anything; does anyone know exactly what he stated about the VAB in that book? It certainly seems a bit quote miney to me considering the title. Cheers, Trebor Hi I do have a copy of the book, not immediately to hand. The first thing to understand is that the claims relate to generational ships, i.e. ships whose crews will have to deal with radiation exposure over their entire lifetime. GCRs become a major issue in this case. Absolutely no mention of short duration trips from Earth to Moon. IIRC, the claim for 2m water shielding was to protect against solar flares. Unlike Apollo missions, the crew of an interstellar ship wouldn't have a handy Earth nearby where they could quickly retreat to for safety and possible medical attention if caught in a major solar storm. They would need a way of effectively reducing the exposure virtually to zero. Hence the requirement for extensive shielding. Unfortunately, some HBs have seized on this as all the proof they need that Apollo shielding wasn't sufficient. When I've pointed out that Mauldin's book specifically refers to interstellar missions lasting decades (rather than days), they say it's irrelevant. I don't recall any mention of shielding required for passing through the Van Allen belts. The 2m claim was specifically for protecting against solar flares (and probably GCRs). If you need any more info, let me know and I'll hunt out the relevant passages and copy them for you. |
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Post by Data Cable on Apr 9, 2010 5:29:11 GMT -4
Why would anyone assume that specifications for radiation shielding from a book entitled "Prospects for Interstellar Travel" would apply only to the Van Allen belts, a phenomenon extremely localized to the earth?
[edit: corrected errant punctuation after sentence re-structuring]
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Jason
Pluto
May all your hits be crits
Posts: 5,579
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Post by Jason on Apr 9, 2010 11:20:03 GMT -4
Why would anyone assume that specifications for radiation shielding from a book entitled "Prospects for Interstellar Travel" would apply only to the Van Allen belts, a phenomenon extremely localized to the earth? [edit: corrected errant punctuation after sentence re-structuring] Because HBs don't understand the difference between interstellar and interlunar? |
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Post by Data Cable on Apr 9, 2010 11:43:20 GMT -4
Because HBs don't understand the difference between interstellar and interlunar? Wouldn't "interlunar" travel be from one moon to another? |
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Post by randombloke on Apr 9, 2010 12:44:25 GMT -4
Because HBs don't understand the difference between interstellar and interlunar? Wouldn't "interlunar" travel be from one moon to another? Possibly. Doesn't mean HB's know it different from the other. Or a trip to the Kwik-E-Mart. As for your first question, I often get the impression that HBs believe some terribly apocryphal things about the VABs, not the least of which is that they extend at least as far as the moon. Or, more likely that, if the moon orbits the earth and the VABs are in earth orbit, the moon must be near or in the VABs... |
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Jason
Pluto
May all your hits be crits
Posts: 5,579
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Post by Jason on Apr 9, 2010 13:48:05 GMT -4
Well, it's not really interplanetary travel when its from one planet to a moon, is it? What's the proper word if not "interlunar"?
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Apr 9, 2010 14:50:38 GMT -4
"Lunar" would do it.
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Post by LunarOrbit on Apr 9, 2010 14:53:58 GMT -4
Translunar?
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Jason
Pluto
May all your hits be crits
Posts: 5,579
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Post by Jason on Apr 9, 2010 15:37:07 GMT -4
I thought about that one, but doesn't it mean " beyond the moon's orbit"? |
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Post by LunarOrbit on Apr 9, 2010 16:11:05 GMT -4
Maybe... but didn't NASA call the part of the Apollo flight between the Earth and the Moon the "translunar coast"?
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Apr 9, 2010 16:15:38 GMT -4
Doesn't "cis-lunar" refer to the region between Earth and the Moon?
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