Author Topic: Radiation  (Read 616931 times)

Offline JayUtah

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Re: Radiation
« Reply #120 on: March 25, 2018, 12:41:14 AM »
It doesn't take a rocket scientist to determine that a rocket doesn't work.

By definition it does.  So am I to understand that you have no training or experience in spacecraft design?  A simple answer without excuses or distractions would be appreciated.
"Facts are stubborn things." --John Adams

Offline JayUtah

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Re: Radiation
« Reply #121 on: March 25, 2018, 12:44:24 AM »
What have you got?  Refute any point with documentation.  I'm waiting...

While you're waiting, please answer some of the questions I've asked you.  They're designed either to test your assumptions, which may be faulty, or to lead you to information you may not have previously considered in forming your opinion.

Again, you seem to labor under the misconception that the only acceptable refutation of your argument is a lengthy, documented counterclaim.  While an affirmative rebuttal is appropriate in some cases, it is by no means required.  The elementary problem with your argument is that it is no more than a set of uninformed opinions and misconceptions.  Pointing out that this is the case is sufficient to refute it.  The debate you want is not always the debate that's most effective.
"Facts are stubborn things." --John Adams

Offline timfinch

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Re: Radiation
« Reply #122 on: March 25, 2018, 12:45:59 AM »
You are incapable of contesting any of the salient points...

I've been asking you questions designed to demonstrate the actual scientific principles at work.  You won't answer any of them and insist on this sort of bluster.

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...and you waste time attacking my credentials.

As long as your argument consists of nothing but measuring the facts against your expectations, the basis of those expectations remains a valid point of rebuttal.  You are leveling the sorts of judgments that would be evidentiary only if made from a position of expertise.  It does you no good to wish that the problem with your argument were something else.

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Demonstrate a level of understanding by showing why my points are invalid.

Your points are invalid because they are entirely based on judgment you've conceded you're not qualified to give.  Attempts to show you specific deficiencies in your understanding are met only with emotional outbursts, bluster, and attempts to shift the burden of proof.

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Give me something to work with and I can change my mind.

Several people have tried reasoning Socratically with you, asking you questions designed to challenge your preconceptions and assumptions.  You are unwilling to relax any of them.

That is not true.  The only questions asked of me was to provide documentation and of my skill level.  I was asked to justify my qualifications to question the status quo.

Offline timfinch

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Re: Radiation
« Reply #123 on: March 25, 2018, 12:47:44 AM »
What have you got?  Refute any point with documentation.  I'm waiting...

While you're waiting, please answer some of the questions I've asked you.  They're designed either to test your assumptions, which may be faulty, or to lead you to information you may not have previously considered in forming your opinion.

Again, you seem to labor under the misconception that the only acceptable refutation of your argument is a lengthy, documented counterclaim.  While an affirmative rebuttal is appropriate in some cases, it is by no means required.  The elementary problem with your argument is that it is no more than a set of uninformed opinions and misconceptions.  Pointing out that this is the case is sufficient to refute it.  The debate you want is not always the debate that's most effective.

You are full of yourself aren't you?  That is almost insulting.

Offline timfinch

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Re: Radiation
« Reply #124 on: March 25, 2018, 12:48:13 AM »
Early on, it was suggested that cosmic rays could penetrate the Apollo spacecraft. From “Biomedical Results of Apollo” section IV, chapter 2, Apollo Light Flash Investigations we have the following account:

Crewmembers of the Apollo 11 mission were the first astronauts to describe an unusual visual phenomenon associated with space flight. During transearth coast, both the Commander and the Lunar Module Pilot reported seeing faint spots or flashes of light when the cabin was dark and they had become dark-adapted. It is believed that these light flashes result from high energy, heavy cosmic rays penetrating the Command Module structure and the crew members’ eyes. These particles are thought to be capable of producing, visual sensations through interaction with the retina, either by direct deposition of ionization energy in the retina or through creation of visible light via the Cerenkov effect.

When Galactic Cosmic Rays collide with another atom, such as those contained in the Aluminum, Stainless Steel or Titanium structures of a spacecraft, they can create a shower of secondary particles, These secondary particles cause radiation damage in living organisms (humans).

Offline JayUtah

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Re: Radiation
« Reply #125 on: March 25, 2018, 12:51:16 AM »
That is not true.  The only questions asked of me was to provide documentation...

I asked you about the GCR energy spectrum.  I asked you if it would be proper for layman to attempt to operate a nuclear submarine powerplant.

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...and of my skill level.

Not "skill level" per se, but the basis of knowledge that would give your personal judgments some evidentiary value.  You vacillated between claiming expertise is needed and claiming your conclusions were self-evident.

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I was asked to justify my qualifications to question the status quo.

You were asked your qualifications to question a spacecraft design in specific ways.  I'm not making an ideological judgment.  I'm asking whether your analysis of a spacecraft design is based on any prior experience designing and building spacecraft.
"Facts are stubborn things." --John Adams

Offline JayUtah

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Re: Radiation
« Reply #126 on: March 25, 2018, 12:54:19 AM »
These secondary particles cause radiation damage in living organisms (humans).

They can cause radiation damage in living organisms, depending on the flux, the energy, and the biological effect factors.  No one is claiming the Apollo astronauts were not exposed to radiation during their flight.  You're the one claiming the observed effects are not consistent with the claimed mission in the claimed spacecraft.  We are trying to drill down to your reasons for thinking this.  We've already encountered a number of misconceptions on your part, and tried to correct you on them.
"Facts are stubborn things." --John Adams

Offline timfinch

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Re: Radiation
« Reply #127 on: March 25, 2018, 12:56:07 AM »
Problems with shields arise when space radiation particles interact with the atoms of the shield itself. These interactions lead to
production of nuclear byproducts called secondaries (neutrons and other particles). If the shield isn’t thick enough to contain
them, the secondaries that enter the spacecraft can be worse for astronauts’ health than the primary space radiation. Surprisingly,
heavier elements such as lead produce more secondary radiation than lighter elements such as carbon and hydrogen. Consequently,
a great deal of research has been performed on a lightweight polyethylene plastic, called RFX1, which is composed entirely of
lightweight carbon and hydrogen atoms.6
 Research shows that polyethylene is 50% better at shielding solar flares and is 15%
better at shielding galactic cosmic radiation as compared to aluminum. Water is another hydrogen-rich molecule that can absorb
radiation. However, the oxygen content in water makes it a lot heavier than polyethylene, and therefore is much more expensive
to launch. Generally, lighter shields can greatly reduce the harmful effects of incoming space radiation particles, but they cannot
completely stop them.

Offline bknight

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Re: Radiation
« Reply #128 on: March 25, 2018, 12:59:28 AM »
I have provided the documents to justify my position.  I can lead you to the fountain of knowledge but I cannot make you drink.  If you have Information contrary to the information I have provided I would love to see it.

Your data sets are correct, but the analysis of the amount of radiation that Apollo "should have received by you estimation isn't correct.

Jay is just trying to get you to understand the fact that you do not possess the comprehensive knowledge to make a judgment on why the data is correct, nothing more.

The burden of proof is with you not the other way around.  The world's academia has seen the data and does not dispute the Moon landings, why do you think you are smarter more intelligent than them?
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline timfinch

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Re: Radiation
« Reply #129 on: March 25, 2018, 01:00:00 AM »
2.1 Shielding of Galactic Cosmic Rays
The GCRs of interest have charge number, Z from 1 to 28, and energy from less than 1 MeV/u
to more than 10,000 MeV/u with a median energy of about 1,000 MeV/u. The GCRs with
energies less than about 2,000 MeV/u are modulated by the 11-year solar cycle, with more than
two-times higher GCR flux at solar minimum when the solar wind is weakest compared to the
flux at solar maximum. The most recent solar minimum was in 2008-2009, and the next will
occur in 2019-2020. Engineering considerations on material strength, temperature, ultraviolet
degradation, flammability, etc., must be considered alongside of radiation protection, and the
composite picture must be analyzed. Materials with the smallest mean atomic mass are usually
the most efficient shields for both SPE and GCR, as described next. The composition of the
radiation field changes as particles lose energy and suffer nuclear interactions in traversing
structural materials, instruments, and the tissues of astronauts. Both the energy loss and the
changes in particle fluence are related to the number of atoms per unit mass (in units such as
grams) in the traversed material, which, in turn, is proportional to Avogadro's number divided by
the atomic mass number, AT, for each element of the material. The energy loss by ionization of
a single component of shielding material with atomic number ZT is proportional to the number of
electrons per atom and thus proportional to ZT/AT. However, the energy lost per gram of material
and per incident fluence (e.g., in units of particles per cm2
), the “mass stopping power,” is also
inversely proportional to the density,  (e.g., in g/cm3
) of the material, so that the energy lost by
one incident particle per cm2
 per unit mass is proportional to Z/A.
The number of nuclear interactions per unit mass and per unit incident fluence is proportional to
/A, where  is the total nuclear reaction cross section (Wilson et al., 1991; 1995). To a first
approximation,  is proportional to A2/3, so that the nuclear transmission is proportional to 1/A1/3
.
The ratio of electronic stopping power to nuclear interaction transmission is therefore
proportional to Z/ A2/3. Materials with small atomic mass have the highest number of electrons
per nucleon (e.g., Z/A is 1 for hydrogen, 0.5 for carbon, 0.48 for aluminum, 0.46 for iron, and
0.40 for lead). Light mass materials have smaller nuclei and therefore more of them can fit into a

Offline JayUtah

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Re: Radiation
« Reply #130 on: March 25, 2018, 01:02:25 AM »
Problems with...

Yes, you've shown your ability to copypaste from hastily Googled material.  I guarantee that every single person you're speaking to in this forum is well aware of secondary radiation.  I'm an engineer.  I've been a fully-qualified engineer for more than 30 years.

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Research shows that polyethylene is 50% better at shielding solar flares and is 15% better at shielding galactic cosmic radiation as compared to aluminum.

Yes, there are materials that are optimal for shielding against radiation.  There are other materials that are optimal for making a rigid spacecraft structure.  There are still other materials that are optimal for thermal conductivity and response.  The proper design of a spacecraft incorporates all those constraints and makes proper tradeoffs among them in order to satisfy mission objectives and constraints.

I keep asking you if you have any experience in the methods used to design spacecraft, such that you would have been trained and tested on these concepts.  Why is it so hard to get an answer on this out of you?
"Facts are stubborn things." --John Adams

Offline timfinch

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Re: Radiation
« Reply #131 on: March 25, 2018, 01:03:26 AM »
I have provided the documents to justify my position.  I can lead you to the fountain of knowledge but I cannot make you drink.  If you have Information contrary to the information I have provided I would love to see it.

Your data sets are correct, but the analysis of the amount of radiation that Apollo "should have received by you estimation isn't correct.

Jay is just trying to get you to understand the fact that you do not possess the comprehensive knowledge to make a judgment on why the data is correct, nothing more.

The burden of proof is with you not the other way around.  The world's academia has seen the data and does not dispute the Moon landings, why do you think you are smarter more intelligent than them?

I imagine Orville and Wilbur was asked the same question.  My answer to such a profound question is I am not as susceptible to public opinion as the majority of people (Sheeple) are.

Offline JayUtah

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Re: Radiation
« Reply #132 on: March 25, 2018, 01:06:03 AM »
2.1 Shielding of Galactic Cosmic Rays

Tim,

Copypasting walls of text that you clearly don't understand is not a substitute for a discussion and debate of your claims.  You may be laboring under the false notion that simply copypasting material validates your judgment.  It does not.  Once again, you can cite all the material you want about what materials are optimal.  That does not mean those are the materials that are actually used.  Knowing what is actually used is not a matter of frantic Googling or of guesswork.  You either know how spacecraft are actually made or you don't.  In practical terms, only the ISS uses polyethylene shielding for radiation attenuation.  Can you guess why that is?
"Facts are stubborn things." --John Adams

Offline timfinch

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Re: Radiation
« Reply #133 on: March 25, 2018, 01:07:49 AM »
Problems with...

Yes, you've shown your ability to copypaste from hastily Googled material.  I guarantee that every single person you're speaking to in this forum is well aware of secondary radiation.  I'm an engineer.  I've been a fully-qualified engineer for more than 30 years.

Quote
Research shows that polyethylene is 50% better at shielding solar flares and is 15% better at shielding galactic cosmic radiation as compared to aluminum.

Yes, there are materials that are optimal for shielding against radiation.  There are other materials that are optimal for making a rigid spacecraft structure.  There are still other materials that are optimal for thermal conductivity and response.  The proper design of a spacecraft incorporates all those constraints and makes proper tradeoffs among them in order to satisfy mission objectives and constraints.

I keep asking you if you have any experience in the methods used to design spacecraft, such that you would have been trained and tested on these concepts.  Why is it so hard to get an answer on this out of you?

I am an electrician by trade and I have never designed anything other than motor controls.

Offline timfinch

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Re: Radiation
« Reply #134 on: March 25, 2018, 01:09:39 AM »
Let me try a different tactic.  Rather than tell you erstwhile gentlemen anything I will simply ask you questions.  How will that work for you?