Author Topic: Radiation  (Read 616913 times)

Offline timfinch

  • Jupiter
  • ***
  • Posts: 865
  • BANNED
Re: Radiation
« Reply #1260 on: April 07, 2018, 10:45:19 AM »
Abstract
A gross survey of data on Van Allen belt radiations, galactic cosmic radiation, and solar cosmic radiation is presented. On the basis of these data that are, in part, fragmentary and uncertain, upper and lower limits of rad doses under different amounts of mass shielding are estimated. The estimates are preliminary especially in the cases of chance encounter with solar flare protons. Generally, the relative biological effectiveness of the high energetic space radiations and their secondaries appear insufficiently known to give detailed biological or rem doses. The overall ionization dosage of the low level galactic cosmic radiation in free space is estimated to be even in solar minimum years equivalent to less than 50 rem/year or 1 rem/week. Mass shielding up to 80 g/cm2 would not reduce the ionization dosage but would shield against heavy primaries and heavy ionizing secondaries, thus reducing the biological dose. The flux of energetic protons in the maximum intensity zone of the inner Van Allen belt is by about four orders of magnitude higher, their energy and penetration power, of course, lower. A shield of 25 g/cm2 would reduce the dose rate from 20 rad/hour under 2 g/cm2 to 5 rad/hour. These proton dose rates and also the electron and X-radiation dose rates under some g/cm2 shielding of low z-number material will not constitute a radiation hazard for flights straight through the inner and outer belt in about two hours. Staying within the maximum of the inner belt for two days would, however, lead even within 25 g/cm2 depth of outer shield and body itself to a dose of 200 rad which is on the permissible limit. Extreme solar cosmic ray events or proton showers of high intensity and a duration of days occurred with a frequency of 1-4 per year during the last highly active cycle. For the penetrating, most intense high energy event of February 23, 1956, the dose within 25 g/cm2 is estimated to have been in the order of 50 rad. In most cases the dose decreased more rapidly with penetration depth and would have been even in multiple events with such high shielding below critical levels, especially on inner organs. On the surface of the body and in a lightly shielded space vehicle or protected by a space suit only the dose can, especially in multiple events, reach values of 1000 rad and more.

https://www.ncbi.nlm.nih.gov/pubmed/12056428
« Last Edit: April 07, 2018, 11:56:53 AM by timfinch »

Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1261 on: April 07, 2018, 10:48:28 AM »
FYI
Hi genius, is the attached a log or linear graph?

Do tell.

Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1262 on: April 07, 2018, 10:58:25 AM »
Abstract
A gross survey of data on Van Allen belt radiations, galactic cosmic radiation, and solar cosmic radiation is presented. On the basis of these data that are, in part, fragmentary and uncertain, upper and lower limits of rad doses under different amounts of mass shielding are estimated. The estimates are preliminary especially in the cases of chance encounter with solar flare protons. Generally, the relative biological effectiveness of the high energetic space radiations and their secondaries appear insufficiently known to give detailed biological or rem doses. The overall ionization dosage of the low level galactic cosmic radiation in free space is estimated to be even in solar minimum years equivalent to less than 50 rem/year or 1 rem/week. Mass shielding up to 80 g/cm2 would not reduce the ionization dosage but would shield against heavy primaries and heavy ionizing secondaries, thus reducing the biological dose. The flux of energetic protons in the maximum intensity zone of the inner Van Allen belt is by about four orders of magnitude higher, their energy and penetration power, of course, lower. A shield of 25 g/cm2 would reduce the dose rate from 20 rad/hour under 2 g/cm2 to 5 rad/hour. These proton dose rates and also the electron and X-radiation dose rates under some g/cm2 shielding of low z-number material will not constitute a radiation hazard for flights straight through the inner and outer belt in about two hours. Staying within the maximum of the inner belt for two days would, however, lead even within 25 g/cm2 depth of outer shield and body itself to a dose of 200 rad which is on the permissible limit. Extreme solar cosmic ray events or proton showers of high intensity and a duration of days occurred with a frequency of 1-4 per year during the last highly active cycle. For the penetrating, most intense high energy event of February 23, 1956, the dose within 25 g/cm2 is estimated to have been in the order of 50 rad. In most cases the dose decreased more rapidly with penetration depth and would have been even in multiple events with such high shielding below critical levels, especially on inner organs. On the surface of the body and in a lightly shielded space vehicle or protected by a space suit only the dose can, especially in multiple events, reach values of 1000 rad and more.

https://www.ncbi.nlm.nih.gov/pubmed/12056428
Irrelevant. You have been told why repeatedly.

Offline timfinch

  • Jupiter
  • ***
  • Posts: 865
  • BANNED
Re: Radiation
« Reply #1263 on: April 07, 2018, 11:07:04 AM »

Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1264 on: April 07, 2018, 11:10:11 AM »
FYI
Hi genius, is the attached a log or linear graph?

Do tell.

https://en.wikipedia.org/wiki/Logarithmic_scale
I asked you, not wiki.

Is that a log or linear graph?

You don't know, do you?

Offline bknight

  • Neptune
  • ****
  • Posts: 3107
Re: Radiation
« Reply #1265 on: April 07, 2018, 11:12:35 AM »
FYI
Hi genius, is the attached a log or linear graph?

Do tell.

https://en.wikipedia.org/wiki/Logarithmic_scale
I asked you, not wiki.

Is that a log or linear graph?

You don't know, do you?

*Raises Hand Quickly*

I know, I know.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan


Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1267 on: April 07, 2018, 11:25:03 AM »
http://stockcharts.com/articles/mailbag/2014/11/what-is-the-difference-between-a-logarithmic-and-arithmetic-chart.html
I asked for your answer not some random website that does not address the specific graph I posted.

What is YOUR answer?

Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1268 on: April 07, 2018, 11:38:55 AM »
FYI
Hi genius, is the attached a log or linear graph?

Do tell.

https://en.wikipedia.org/wiki/Logarithmic_scale
I asked you, not wiki.

Is that a log or linear graph?

You don't know, do you?

*Raises Hand Quickly*

I know, I know.
Now, now. Let timfinch demonstrate his knowledge.

Offline Luke Pemberton

  • Uranus
  • ****
  • Posts: 1823
  • Chaos in his tin foil hat
Re: Radiation
« Reply #1269 on: April 07, 2018, 11:39:31 AM »
Tim

You're now behaving like a petulant child that couldn't make his point so sulked for a couple of days. Your cutting and pasting is the equivalent of sticking your fingers in your ears and screaming, and disregarding everyone else in the room.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former - Albert Einstein.

I can calculate the motion of heavenly bodies, but not the madness of people – Sir Isaac Newton.

A polar orbit would also bypass the SAA - Tim Finch

Offline timfinch

  • Jupiter
  • ***
  • Posts: 865
  • BANNED
Re: Radiation
« Reply #1270 on: April 07, 2018, 11:42:31 AM »

Offline Abaddon

  • Saturn
  • ****
  • Posts: 1132
Re: Radiation
« Reply #1271 on: April 07, 2018, 11:52:13 AM »
http://stockcharts.com/articles/mailbag/2014/11/what-is-the-difference-between-a-logarithmic-and-arithmetic-chart.html
I asked for your answer not some random website that does not address the specific graph I posted.

What is YOUR answer?
That is NOT an answer. I didn't ask you to post other random graphs, I asked you about the one I posted.

What is YOUR answer?

Offline Zakalwe

  • Uranus
  • ****
  • Posts: 1588
Re: Radiation
« Reply #1272 on: April 07, 2018, 11:58:26 AM »
In 1972, Apollo astronaut Harrison Schmitt sniffed the air in his Lunar Module, the Challenger. "[It] smells like gunpowder in here," he said. His commander Gene Cernan agreed. "Oh, it does, doesn't it?"

The two astronauts had just returned from a long moonwalk around the Taurus-Littrow valley, near the Sea of Serenity. Dusty footprints marked their entry into the spaceship. That dust became airborne--and smelly.


see caption

Right: Moonwalking astronaut Harrison Schmitt. [More]
Later, Schmitt felt congested and complained of "lunar dust hay fever." His symptoms went away the next day; no harm done. He soon returned to Earth and the anecdote faded into history.

https://science.nasa.gov/science-news/science-at-nasa/2005/22apr_dontinhale

So now you're using quotations from astronauts that went to the Moon to support your claim that no astronauts went to the Moon.  ::)


 
"The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.' " - Isaac Asimov

Offline molesworth

  • Mars
  • ***
  • Posts: 349
  • the curse of st custards
Re: Radiation
« Reply #1273 on: April 07, 2018, 11:59:02 AM »
Abstract

<snipped for conciseness>

https://www.ncbi.nlm.nih.gov/pubmed/12056428
Published in 1963, five years before the first mission beyond LEO, and, as it says in the title and notes in the abstract, is discussing estimates of likely doses.  What additional information was available by the time Apollo 8 was launched, and what conclusions were drawn from it?  Have you looked in detail at the refinement of measurements and modelling of the radiation environment since the beginning of space flight?

Also, on my reading of the abstract, it implies that with proper shielding and routing, missions beyond LEO should not present unsurvivable hazards.  I'll leave discussion of the actual estimated doses and shielding to people who understand these things better than I do.

I would also ask, what further detail is provided in the full paper?  You shouldn't base any discussion or conclusions purely on the abstract.  Again, not being an expert in this area I won't go through it myself, but if you're going to be discussing estimates, measurements and analysis of the radiation in space, you need to do more than copy a few abstracts or selected graphs - you need to do a proper literature search and take the time to read, understand, and where necessary, analyse the data.
Days spent at sea are not deducted from one's allotted span - Phoenician proverb

Offline Luke Pemberton

  • Uranus
  • ****
  • Posts: 1823
  • Chaos in his tin foil hat
Re: Radiation
« Reply #1274 on: April 07, 2018, 12:05:10 PM »
So now you're using quotations from astronauts that went to the Moon to support your claim that no astronauts went to the Moon.  ::)

I missed that, even though I asked him whether he thought they was exposed to the dust. Duh!

It reminds me of a user called stalkervision over at YT many years ago. He was arguing the line 'they could never leave Earth's orbit radiation is bad' argument. Then is his next breath he claimed that they never left Earth's orbit because on Apollo 8 the crew saw aliens, so NASA did not want to send manned missions.  ??? :o :-\
« Last Edit: April 07, 2018, 12:20:07 PM by Luke Pemberton »
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former - Albert Einstein.

I can calculate the motion of heavenly bodies, but not the madness of people – Sir Isaac Newton.

A polar orbit would also bypass the SAA - Tim Finch