Author Topic: Radiation  (Read 635627 times)

Offline nomuse

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Re: Radiation
« Reply #1800 on: April 10, 2018, 11:20:17 PM »
Ah, of course. Because every lump would have lumps, and it's elephants, young man, all the way down.

Offline Jason Thompson

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Re: Radiation
« Reply #1801 on: April 11, 2018, 03:58:30 AM »
I eluded to this point a few posts ago....
as you elude to in you post...

Sorry to nitpick, but you allude to something. To elude means to escape from something.

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Only in the event of an SPE do the levels spike.

And this is where understanding the scale and the numbers on the axis comes into play. On the log scale the CraTer data appears to be full of big, dangerous-looking spikes. However, only four of them get above 10cGy/day (0.1Gy/day) and only two exceed 100cGy/day (1Gy/day). If big, life-threatening spikes are what you're interested in then a linear plot is actually more clear visually. To put that in context a quick Google search (not the most academic of methods but gives an idea) for radiation effects in humans suggests 0.3Gy makes you ill, 1-4gy makes you very ill but you can be saved with medical intervention, 4-8Gy makes you extremely ill and might kill you within weeks of exposure even if you do get treatment. 8-30Gy makes you acutely ill and kills you within days of exposure and over 30Gy is certain death within two days. So put like that it is clear that over the entire cycle only a very small number of occasions occurred that would present even significant threats to the health of any astronauts on a two-week flight, Only two that present threat to life during the mission, and that's only because any radiation sickness would likely impair their ability to operate the spacecraft to return safely to Earth where they could be treated for it. All of this is before you account for the different shielding properties of their spacecraft versus the detectors used to gather these data.
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Offline Luke Pemberton

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Re: Radiation
« Reply #1802 on: April 11, 2018, 06:06:36 AM »
Sorry to nitpick, but you allude to something. To elude means to escape from something.

Ha! It's one of my common mistakes. My friend caught the same mistake not so long ago on Facebook. I'll make it again, I'm sure. Pedal and peddle is one I have to think about too.

I'm OK, with your and you're, to, too and two, there, their and they're - thankfully!  ;)
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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 BazBear

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Re: Radiation
« Reply #1803 on: April 11, 2018, 07:15:08 AM »
I screw up choosing its or it's far too often.
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Offline Luke Pemberton

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Re: Radiation
« Reply #1804 on: April 11, 2018, 10:05:15 AM »
All of this is before you account for the different shielding properties of their spacecraft versus the detectors used to gather these data.

... and of course, with warning, they could turn the spacecraft around so the CSM faces the incoming proton flux and offers increased shielding; eluding some components of the SPE flux. As alluded to in many discussions on this topic at fora and accounts in the literature. There is no eluding this issue, SPEs are the main danger.

I screw up choosing its or it's far too often.

I'm sure I make that mistake often.
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 gillianren

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Re: Radiation
« Reply #1805 on: April 11, 2018, 11:13:12 AM »
I screw up choosing its or it's far too often.

If it helps, "its" parallels "yours" and "ours" and so forth.  None of them take an apostrophe, either.
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Offline nomuse

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Re: Radiation
« Reply #1806 on: April 11, 2018, 11:20:23 AM »
I just assume I've got it wrong, and will go back over every one in a quick edit pass.

(I know the rules, but the mind has the terrible ability to edit what it thinks it didn't and vice-versa.)

Offline Jason Thompson

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Re: Radiation
« Reply #1807 on: April 11, 2018, 01:19:32 PM »
... and of course, with warning,

Another bit Tim either didn't get or pretended not to get. He was quite happy to talk about SPEs but apparently still thought they travelled at light speed....
 
Quote
they could turn the spacecraft around so the CSM faces the incoming proton flux and offers increased shielding; eluding some components of the SPE flux. As alluded to in many discussions on this topic at fora and accounts in the literature. There is no eluding this issue, SPEs are the main danger.

 ;D ;D ;D ;D ;D ;D
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Offline Luke Pemberton

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Re: Radiation
« Reply #1808 on: April 11, 2018, 01:46:19 PM »
And this is where understanding the scale and the numbers on the axis comes into play. On the log scale the CraTer data appears to be full of big, dangerous-looking spikes. However, only four of them get above 10cGy/day (0.1Gy/day) and only two exceed 100cGy/day (1Gy/day). If big, life-threatening spikes are what you're interested in then a linear plot is actually more clear visually. To put that in context a quick Google search (not the most academic of methods but gives an idea) for radiation effects in humans suggests 0.3Gy makes you ill, 1-4gy makes you very ill but you can be saved with medical intervention, 4-8Gy makes you extremely ill and might kill you within weeks of exposure even if you do get treatment. 8-30Gy makes you acutely ill and kills you within days of exposure and over 30Gy is certain death within two days. So put like that it is clear that over the entire cycle only a very small number of occasions occurred that would present even significant threats to the health of any astronauts on a two-week flight, Only two that present threat to life during the mission, and that's only because any radiation sickness would likely impair their ability to operate the spacecraft to return safely to Earth where they could be treated for it. All of this is before you account for the different shielding properties of their spacecraft versus the detectors used to gather these data.

I found this link which shows the date of SPEs that took place during the Apollo missions. The graphic illustrates quite nicely that not all SPEs are equal. When one researches the literature, the solar storm of 1972 is always considered a big one, along with the Halloween storm of 2003. The Carrington event is considered the largest in recorded history if I recall, similar in magnitude to the storm of 2012 that thankfully missed the Earth.

Apollo and SPEs

On the International Space Station there is a special thick-walled room to which the astronauts have had to retreat during times of increased solar radiation.

Unless I'm incorrect, this suggests astronauts can take action in the event of a solar proton event. I understand from SOHO data that the initial proton flux rises suddenly, but the SPE occurs over hours or days, so the dose is not received in an instant. An SPE is not a spike in radiation.
« Last Edit: April 11, 2018, 02:06:13 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

Offline molesworth

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Re: Radiation
« Reply #1809 on: April 11, 2018, 04:57:57 PM »
This is what working with an exponential arithmetic scale using log data would be like.


Wow!  Now that is complex!!  ;D <pun intended>

An interesting choice of colours that brings out my synesthesia, and I can taste them all the way down  :o
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Offline inconceivable

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Re: Radiation
« Reply #1810 on: April 11, 2018, 05:00:21 PM »
But  then we have still have the issue of the glass windows in the LEM and the CM and not to mention the helmets.  Sure they can handle the heat of reentry but no Nasa documentation on radiation protection and micrometeoroids.  The space shuttle's fused silicon GLASS which was in low Earth orbit had a record average replacement of 1 window replacement every 10.8 days in orbit.  The higher the altitude the mean impact rate increased.  Shielding is required over 124.34 miles altitude and more research is needed for better shielding over 330 miles altitude.     This is basically the same fused silicon glass the Soyuz and the new Orion will be using.  Ironically there is no mention of Apollo/Gemini radiation protection of  high temp quartz GLASS.  The Boeing x-37 shuttle is doing the preliminary testing of crafts with no windows and HUD with cameras and screens and advanced electronics capable of traveling in the Van Allen Belts.  To go the moon and deep space it is known that windows have to go.   Glass is like having an open window in space to radiation.  3oh.e

Offline bknight

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Re: Radiation
« Reply #1811 on: April 11, 2018, 05:09:48 PM »
But  then we have still have the issue of the glass windows in the LEM and the CM and not to mention the helmets.  Sure they can handle the heat of reentry but no Nasa documentation on radiation protection and micrometeoroids.  The space shuttle's fused silicon GLASS which was in low Earth orbit had a record average replacement of 1 window replacement every 10.8 days in orbit.  The higher the altitude the mean impact rate increased.  Shielding is required over 124.34 miles altitude and more research is needed for better shielding over 330 miles altitude.     This is basically the same fused silicon glass the Soyuz and the new Orion will be using.  Ironically there is no mention of Apollo/Gemini radiation protection of  high temp quartz GLASS.  The Boeing x-37 shuttle is doing the preliminary testing of crafts with no windows and HUD with cameras and screens and advanced electronics capable of traveling in the Van Allen Belts.  To go the moon and deep space it is known that windows have to go.   Glass is like having an open window in space to radiation.  3oh.e

Firstly it wasn't made of glass but polycarbonate, if you would have bothered to look.

https://airandspace.si.edu/collection-objects/helmet-pressure-bubble-aldrin-apollo-11
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Offline Luke Pemberton

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Re: Radiation
« Reply #1812 on: April 11, 2018, 05:21:38 PM »
To go the moon and deep space it is known that windows have to go.   Glass is like having an open window in space to radiation.

If you have read this thread, it is agreed that the CM offered little protection to GCR. However, on a short mission to the moon and the return journey, GCR does not present a problem in terms of the dose the astronauts received.
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 Jason Thompson

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Re: Radiation
« Reply #1813 on: April 11, 2018, 05:42:26 PM »
But  then we have still have the issue of the glass windows in the LEM and the CM and not to mention the helmets.

Why is this still an issue when we have just spent hundreds of pages showing how low radiation in space actually is when it comes to serious health concerns for a two week flight?

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no Nasa documentation on radiation protection and micrometeoroids

None? Or just none you've been able to pull up from a google search? Huge difference.

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Glass is like having an open window in space to radiation.

Is it? What kind of radiation? How energetic? Come on, inconceivable, engage with the thread. My question as to your reasons for being here still stands since you steadfastly refuse to actually discuss and to respond when people reply to you.
"There's this idea that everyone's opinion is equally valid. My arse! Bloke who was a professor of dentistry for forty years does NOT have a debate with some eejit who removes his teeth with string and a door!"  - Dara O'Briain

Offline nomuse

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Re: Radiation
« Reply #1814 on: April 11, 2018, 06:00:31 PM »
I suspect strongly there are MORE impacts in LEO, not fewer. First, gravity will tend to perturb objects towards Earth, as well as entrap them in various elliptical paths. Second, LEO is where we've been. Ask any archaeologist; where people go, is garbage. LEO is where space junk is. Worse, the stuff is more-or-less already in the orbital paths you want to have your shuttle orbiter in.