Radiation

[Jason Thompson]

Well, with the usual lack of hope of a reply from inconceivable...

The one thing that gets me about the radiation question is about the space suits.  They offered layers of protection for the body.  But the most critical part of a human is the brain and the helmet provided the least protection to the astronaut.

Really? What data do you have regarding the shielding effectiveness of the polycarbonate (most definitely not glass) helmet plus the additional layers used during EVA with all the visors etc.?

Lab tests on mice have concluded that mice lost cognitive skills with an equivalent of 10 day exposure to charged particles 16O, Ti48.

1: Citation please.
2: How closely does this replicate the environment in space?
3: How many astronauts are outside the spacecraft for anything close to 10 days?
4: How does the effect on a mouse's brain compare to a human brain?

How much protection can the glass in the helmet provide other than UV protection?

It's not glass.

If Apollo missions helmets offered this much protection,

How much, against what? Your argument makes no logical sense in the absence of anyhting resembling data.

shouldn't they make spacecrafts out of glass for deep space missions?

Thank you for demonstrating once again you have little interest beyond yanking chains here. The necessity for tradeoffs based on mission requirements and the lack of an ideal material that meets all of them has been explained repeatedly on this thread.
[/quote]

[JayUtah]

And of course all those materials that list or compute the effective dose for blood-forming organs.  Aren't they going to feel silly when inconceivable tells them that was the wrong set of organs and that they should have been looking at the brain all along.

[raven]

Yeah, I may not know too much about the A7L spacesuit helmets, but I know they're not made of freaking glass. Did a wild search engine kill your parents or something, inconceivable?

[bknight]

Yeah, I may not know too much about the A7L spacesuit helmets, but I know they're not made of freaking glass. Did a wild search engine kill your parents or something, inconceivable?

Polycarbonate

https://airandspace.si.edu/collection-objects/helmet-pressure-bubble-apollo-a7-l-experimental

Would that due for a low density hydrogen compound?

[Obviousman]

The back of the helmet, apart from offering a padded surface for launch and re-entry, also provide some shielding IIRC.

[raven]

Yeah, I may not know too much about the A7L spacesuit helmets, but I know they're not made of freaking glass. Did a wild search engine kill your parents or something, inconceivable?

Polycarbonate

https://airandspace.si.edu/collection-objects/helmet-pressure-bubble-apollo-a7-l-experimental

Would that due for a low density hydrogen compound?

Heh, I'm sure some  conspiracy theorist somewhere is going bonkers about a spacesuit helmet with airholes.

[Luke Pemberton]

Aluminum is useless in shielding GCR's and in fact increase biological dosing due to secondary emissions from the high energy protons.

You're cherry picking the same research that Jarrah White cherry picked. It is indeed true that aluminum alone creates secondary radiation from GCR to fragmentation of primary GCR radiation. This is due to aluminum having Z = 13. There is a much higher cross section of interaction between the aluminum nucleus and high energy protons, which results in greater fragmentation.

The research that you cite applies to the ISS, as ISS traverses the SAA and the issue of high energy protons is pertinent. The researchers addressed the issue of using polymer materials as these have a low Z compared to aluminum shielding. The researchers found that it was best to use polythene shielding in tandem with aluminum to reduce secondary radiation from high energy protons.

At least that is my understanding.

[Luke Pemberton]

I understand he has flounced, but there are several articles written about secondary radiation several years ago. These were reported in the popular science press. One such example:

https://www.seeker.com/moon-poses-radiation-risk-to-future-travelers-1764980915.html

The line of interest

...the levels [from secondary radiation] were about what an X-ray technician or uranium miner might normally experience in a year.

Although every article refers to the lunar surface as becoming radioactive, which is slightly annoying. 

[Abaddon]

I have fulfilled my quota for entertaining pompous, self-righteous know-it-alls for this quarter.  I'll check back sometime next quarter to see if the light of epiphany has shined on you guys.  Be well and be vigilant.

As usual, you dish out insults and run away in fear that your cherish delusion may not be assaulted. Grow a pair.

[timfinch]

Well,  a new quarter has started and I have a fresh new quota for self-righteous, blow hards.  Let's do this!

I'll lead off with a few facts for your consideration.

The current solar cycle began on January 4, 2008, with minimal activity until early 2010. It is on track to have the lowest recorded sunspot activity since accurate records began in 1750. The cycle featured a "double-peaked" solar maximum. The first peak reached 99 in 2011 and the second in early 2014 at 101. It appears likely that Cycle 24 will end in mid-2018.
This is the graph of dose rate taken by the CraTer Satellite that has been monitoring lunar radiation since 2009.  It is obvious to the casual observer that the background radiation exposure was fairly flat throughout the solar cycle punctuated by SPE events.  It can be deduced by the by even the dullest of intellects that a lunar mission would have as a minimum this background radiation of approximately .3 mgy/day.  Apollo 11 had a .22 mgy/day dose rate.  This is only possible if it never left ELO.


http://crater-web.sr.unh.edu/products.php?numplots=1&durationtype=span&ProductG111=doserates&SepGcrAllType111=all&InvCombG111=doserates_combined&DaysRangeG111=Alldays&syncdate=yes&StartEndGroup111=end&doy111=085&yeargroup111=2017&screenheight=&screenwidth=

[timfinch]

I understand he has flounced, but there are several articles written about secondary radiation several years ago. These were reported in the popular science press. One such example:

https://www.seeker.com/moon-poses-radiation-risk-to-future-travelers-1764980915.html

The line of interest

...the levels [from secondary radiation] were about what an X-ray technician or uranium miner might normally experience in a year.

Although every article refers to the lunar surface as becoming radioactive, which is slightly annoying. 

Why is it you find the truth annoying?  Is it because you realize if the surface of the moon is radioactive then it becomes obvious the astronauts never landed there?  They would have been contaminated and even ingested and breathed radioactive moon dust.  Is that why it is so annoying?

[Luke Pemberton]

Why is it you find the truth annoying?  Is it because you realize if the surface of the moon is radioactive then it becomes obvious the astronauts never landed there?  They would have been contaminated and even ingested and breathed radioactive moon dust.  Is that why it is so annoying?

Explain to me the mechanism by which bombardment of soils with high energy protons makes the soil radioactive. Do you understand the difference between radiation and radioactivity?

Spence [the scientist] is clearly referring secondary radiation due to GCR influx. The article has used poetic licence and uses the much misaligned word radioactive rather than radiation when discussing the hazard of ionising radiation in space.

It's not a case of truth, it's a case of understanding nuclear physics. There's a difference between a truth that fits your narrative and scientific understanding.

[timfinch]

Aluminum is useless in shielding GCR's and in fact increase biological dosing due to secondary emissions from the high energy protons.

You're cherry picking the same research that Jarrah White cherry picked. It is indeed true that aluminum alone creates secondary radiation from GCR to fragmentation of primary GCR radiation. This is due to aluminum having Z = 13. There is a much higher cross section of interaction between the aluminum nucleus and high energy protons, which results in greater fragmentation.

The research that you cite applies to the ISS, as ISS traverses the SAA and the issue of high energy protons is pertinent. The researchers addressed the issue of using polymer materials as these have a low Z compared to aluminum shielding. The researchers found that it was best to use polythene shielding in tandem with aluminum to reduce secondary radiation from high energy protons.

At least that is my understanding.

You said a lot about nothing.  GCR is the background radiation of cislunar space and aluminum provides no shielding and the Apollo craft had no hydrogenous shielding capable of attenuating GCR's so it's mission dose should reflect as a minimum the background GCR + VAB transit + 30% to 40% greater lunar exposure.  It doesn't.

[timfinch]

Why is it you find the truth annoying?  Is it because you realize if the surface of the moon is radioactive then it becomes obvious the astronauts never landed there?  They would have been contaminated and even ingested and breathed radioactive moon dust.  Is that why it is so annoying?

Explain to me the mechanism by which bombardment of soils with high energy protons makes the soil radioactive. Do you understand the difference between radiation and radioactivity?

Spence [the scientist] is clearly referring secondary radiation due to GCR influx. The article has used poetic licence and uses the much misaligned word radioactive rather than radiation when discussing the hazard of ionising radiation in space.

It's not a case of truth, it's a case of understanding nuclear physics. There's a difference between a truth that fits your narrative and scientific understanding.

Any high energy particle with the energy to split an atom can cause the creation of a radioactive isotope that in turn gives off a neuton that can cause an additional isotope formation.  GCR constantly bombard the surface of the moon creating radioactive isotopes that create a secondary neutron flux.  It would be absolutely amazing if the moon's surface was not radioactive.  We could build spaceships out of moon dust that would be impervious to GCR.  It is not my narrative.  I did not write the article claiming the moon is radioactive.  It is your narrative that is questioned by that article.

[onebigmonkey]

I understand he has flounced, but there are several articles written about secondary radiation several years ago. These were reported in the popular science press. One such example:

https://www.seeker.com/moon-poses-radiation-risk-to-future-travelers-1764980915.html

The line of interest

...the levels [from secondary radiation] were about what an X-ray technician or uranium miner might normally experience in a year.

Although every article refers to the lunar surface as becoming radioactive, which is slightly annoying. 

Why is it you find the truth annoying?  Is it because you realize if the surface of the moon is radioactive then it becomes obvious the astronauts never landed there?  They would have been contaminated and even ingested and breathed radioactive moon dust.  Is that why it is so annoying?

And bananas are gamma emitters.