Radiation

[timfinch]

Aluminum results in a net increase in GCR radiation.

No.  Secondary radiation from GCR is not the same as GCR.  Secondary radiation necessarily occurs at significantly lower energies where aluminum shielding is somewhat effective.  If you look at a normalized graph of full-spectrum detected radiation behind a shield versus shield thickness, you see a rise in the first few millimeters (due to secondary radiation created in the outer regions of the shield) followed by a sharp, not-quite-linear drop as millimeters increase.  This is because secondary radiation created in the outer portion of the shield is then absorbed by the inner layers.  The more inner layers, the better.

Why would it be the shielding of choice?

It is the shielding of choice.  That's a fact, whether you choose to acknowledge it or not.  The reason it is so despite your belief is that your belief is wrong.  Specifically, you do not understand the complexity of the different species of radiation as they occur in space.

The fact that the apollo missions had no shielding capable of attenuating GCR is the crux of my belief.  It means mission doses must always reflect background GCR levels and they don't, which is undeniable proof that they never left LEO.

You have in no manner shown that the Apollo missions do not reflect background GCRs.  You have not accounted for ANY of the multiple significant differences between the missions, equipment and timing of Apollo vs MSL/RAD.  Also, because the Sun's magnetic field is responsible for diminishing the flux of GCR's the inverse square law comes into play.  This means the farther from the Sun (and its magnetic field) the higher the GCR flux.  How did you take this into account for your "conclusion"?

The minimum GCR background levels occurred at solar peak and were recorded at .2 mgy/hr.  now if you add the fact that the moon has a higher background radiation than cislunar space as does the trip through the VAB then it is unreasonable to believe that apollo 11's daily dose rate of .22 mgy/day reflects anything but an ELO transit.

[Jason Thompson]

I am curious.  Do you believe the apollo astronauts could have survived a major SPE event beyond the VAB if they were given a couple hours advance notice?

Based on the known situations, the belief is they had a good chance of surviving, dependent upon the precise time in the mission, the intensity of the SPE and various other factors that you are pretty well determined to ignore in favour of radiaiton blast = death in all circumstances. Was it a guarantee they'd survive? No. But the risk was accepted by everyone concerned based on the probabilities and the available data collected over the preceding years.

[Jason Thompson]

The minimum GCR background levels occurred at solar peak

All solar peaks are not created equal.

and were recorded at .2 mgy/hr.

I think you made an error in units there. mGy/day surely?

now if you add the fact that the moon has a higher background radiation than cislunar space

WHat kind of radiation? How much higher?

as does the trip through the VAB

Which part? For how long? What kind of radiation? How much higher?

then it is unreasonable to believe that apollo 11's daily dose rate of .22 mgy/day reflects anything but an ELO transit.

Then why doesn't the entire world's science community, people who are actually educated and professionally engaged to work on this stuff, agree with you?

[timfinch]

I don't want to be the one to burst your bubble but as GCR is inversely proportion to solar activity

Interesting that you should mention this little nugget of information. The sata you are using to assume your baseline GCR was taken in 2012, during solar cycle 24. As it happens, this cycle was quite a subdued one as they go. If you look it up you can see that the sunspot number peaked around 2012 at about 75. The Apollo missions happened in solar cycle 20, and if you look at the sunspot number for that maximum you can see it was significantly higher than that for the entire duration of the lunar flight phase of the Apollo program (between 100 and 150). Have you factored this into your baseline? No, you just took the MSL data and presented it as a constant GCR background level that should be present in all missions beyond LEO.

SPE's are directly proportional and the threat to personnel increases.

Yes, but they are discrete events and are detectable in the EM spectrum before the spacecraft gets hit by the particle flare. They are also directional. A massive flare from a sunspot on the limb of the sun as viewed from Earth won't send the most intense particle radiation anywhere near the spacecraft. So, the ground control team had time to detect a flare, decide if it was going to impact the spacecraft, and arrange some degree of protective action (which basically meant turning the spacecraft so the bulk of it was between the astronauts and the sun to provide maximum shielding).

So you believe the structure of the space craft is adequate shielding for the high energy proton flux of a large SPE?  Can you corroborate that with something other than your opinion?

[gillianren]

Point A, which is a minor point--not everyone here is a gentleman.

Point B, can you please answer why you believe "Apollo was faked" is a more logical answer than "there's something I don't understand"?

[JayUtah]

I am curious.  Do you believe the apollo astronauts could have survived a major SPE event beyond the VAB if they were given a couple hours advance notice?

You haven't nailed down enough of the variables to warrant a discrete yes-or-no answer.  Factors to consider would include the class and type of the event ("major" is too ambiguous), the solar longitude of the eruption, the phase of the mission they were in, and how long survivability is to be reckoned.  The baseline for survivability in a radiation exposure context is designated LD 50/30 -- it is the amount of absorbed radiation that will kill fifty percent of the affected population within 30 days.  There are scenarios in your question, for example, in which the astronauts survive long enough to return to Earth, but expire within a few days or weeks.

[JayUtah]

Can you corroborate that with something other than your opinion?

Whereas your opinion requires no such corroboration?  Do you realize Jason is a professional scientist?  His opinion would be considered evidence in a court of law.

[timfinch]

The minimum GCR background levels occurred at solar peak

All solar peaks are not created equal.

and were recorded at .2 mgy/hr.

I think you made an error in units there. mGy/day surely?

now if you add the fact that the moon has a higher background radiation than cislunar space

WHat kind of radiation? How much higher?

as does the trip through the VAB

Which part? For how long? What kind of radiation? How much higher?

then it is unreasonable to believe that apollo 11's daily dose rate of .22 mgy/day reflects anything but an ELO transit.

Then why doesn't the entire world's science community, people who are actually educated and professionally engaged to work on this stuff, agree with you?

Measurements taken by NASA's Lunar Reconnaissance Orbiter show that the number of high energy particles streaming in from space did not tail off closer to the moon's surface, as would be expected with the body of the moon blocking half the sky.

Rather, the cosmic rays created a secondary — and potentially more dangerous -- shower by blasting particles in the lunar soil which then become radioactive.

"The moon is a source of radiation," said Boston University researcher Harlan Spence, the lead scientist for LRO's cosmic ray telescope. "This was a bit unexpected."

While the moon blocks galactic cosmic rays to some extent, the hazards posed by the secondary radiation showers counter the shielding effects, Spence said at a press conference at the American Geophysical Union meeting in San Francisco this week.

Overall, future lunar travelers face a radiation dose 30 percent to 40 percent higher than originally expected, Spence said.

[JayUtah]

Measurements taken...

Asked and answered.

[MBDK]

Aluminum results in a net increase in GCR radiation.

No.  Secondary radiation from GCR is not the same as GCR.  Secondary radiation necessarily occurs at significantly lower energies where aluminum shielding is somewhat effective.  If you look at a normalized graph of full-spectrum detected radiation behind a shield versus shield thickness, you see a rise in the first few millimeters (due to secondary radiation created in the outer regions of the shield) followed by a sharp, not-quite-linear drop as millimeters increase.  This is because secondary radiation created in the outer portion of the shield is then absorbed by the inner layers.  The more inner layers, the better.

Why would it be the shielding of choice?

It is the shielding of choice.  That's a fact, whether you choose to acknowledge it or not.  The reason it is so despite your belief is that your belief is wrong.  Specifically, you do not understand the complexity of the different species of radiation as they occur in space.

The fact that the apollo missions had no shielding capable of attenuating GCR is the crux of my belief.  It means mission doses must always reflect background GCR levels and they don't, which is undeniable proof that they never left LEO.

You have in no manner shown that the Apollo missions do not reflect background GCRs.  You have not accounted for ANY of the multiple significant differences between the missions, equipment and timing of Apollo vs MSL/RAD.  Also, because the Sun's magnetic field is responsible for diminishing the flux of GCR's the inverse square law comes into play.  This means the farther from the Sun (and its magnetic field) the higher the GCR flux.  How did you take this into account for your "conclusion"?

The minimum GCR background levels occurred at solar peak and were recorded at .2 mgy/hr.  now if you add the fact that the moon has a higher background radiation than cislunar space as does the trip through the VAB then it is unreasonable to believe that apollo 11's daily dose rate of .22 mgy/day reflects anything but an ELO transit.

Once again, you ignore the difference factors I mentioned.  Why?  Also, since some of their trip was in LEO, those days would naturally be lower for their daily dose rate, thereby lowering the overall average for the entire mission.  You have failed to account for that.  Just another empty car in your logic train.

[timfinch]

Point A, which is a minor point--not everyone here is a gentleman.

Point B, can you please answer why you believe "Apollo was faked" is a more logical answer than "there's something I don't understand"?

If the data is to be trusted then Apollo 11's mission dosage doe not reflect that it left LEO.  If in fact it didn't then the mission had to be faked.  The only explanation that I can deduce for such a low mission dosage is either it was faked or the equipment was archaic and incapable of measuring accurately exposure in the VAB and cislunar space.

[Jason Thompson]

So you believe the structure of the space craft is adequate shielding for the high energy proton flux of a large SPE?

It isn't a matter of what I believe, it is a matter of what I know the contingency plans were, and that in any event putting the entire bulk of the spacecraft between the crew and the Sun offers the best option for shielding against a highly directional proton flux. Several layers of metals, plastics, fuel, oxygen and hydrogen tanks and their contents, the phenolic resin of the heat shield, all the equipment and stowage containers on the interior, and so on.

Can you corroborate that with something other than your opinion?

Not my burden of proof. I am telling you what is known about SPEs, the spacecraft and the plans for mitigating the effects of any SPE that happened to fall in the two-week flight window of any given Apollo lunar mission. This is documented, and I'd provide a link except I read it in a book or two, not by trawling online sources. You want to argue it was inadequate, it is your burden of proof to show this is the case.

[timfinch]

Aluminum results in a net increase in GCR radiation.

No.  Secondary radiation from GCR is not the same as GCR.  Secondary radiation necessarily occurs at significantly lower energies where aluminum shielding is somewhat effective.  If you look at a normalized graph of full-spectrum detected radiation behind a shield versus shield thickness, you see a rise in the first few millimeters (due to secondary radiation created in the outer regions of the shield) followed by a sharp, not-quite-linear drop as millimeters increase.  This is because secondary radiation created in the outer portion of the shield is then absorbed by the inner layers.  The more inner layers, the better.

Why would it be the shielding of choice?

It is the shielding of choice.  That's a fact, whether you choose to acknowledge it or not.  The reason it is so despite your belief is that your belief is wrong.  Specifically, you do not understand the complexity of the different species of radiation as they occur in space.

The fact that the apollo missions had no shielding capable of attenuating GCR is the crux of my belief.  It means mission doses must always reflect background GCR levels and they don't, which is undeniable proof that they never left LEO.

You have in no manner shown that the Apollo missions do not reflect background GCRs.  You have not accounted for ANY of the multiple significant differences between the missions, equipment and timing of Apollo vs MSL/RAD.  Also, because the Sun's magnetic field is responsible for diminishing the flux of GCR's the inverse square law comes into play.  This means the farther from the Sun (and its magnetic field) the higher the GCR flux.  How did you take this into account for your "conclusion"?

The minimum GCR background levels occurred at solar peak and were recorded at .2 mgy/hr.  now if you add the fact that the moon has a higher background radiation than cislunar space as does the trip through the VAB then it is unreasonable to believe that apollo 11's daily dose rate of .22 mgy/day reflects anything but an ELO transit.

Once again, you ignore the difference factors I mentioned.  Why?  Also, since some of their trip was in LEO, those days would naturally be lower for their daily dose rate, thereby lowering the overall average for the entire mission.  You have failed to account for that.  Just another empty car in your logic train.

[Jason Thompson]

The only explanation that I can deduce for such a low mission dosage is either it was faked or the equipment was archaic and incapable of measuring accurately exposure in the VAB and cislunar space.

Now explain why 'or I am wrong' is not one of your possible explanations that deserves examination.

[jfb]

I don't want to be the one to burst your bubble but as GCR is inversely proportion to solar activity

Interesting that you should mention this little nugget of information. The sata you are using to assume your baseline GCR was taken in 2012, during solar cycle 24. As it happens, this cycle was quite a subdued one as they go. If you look it up you can see that the sunspot number peaked around 2012 at about 75. The Apollo missions happened in solar cycle 20, and if you look at the sunspot number for that maximum you can see it was significantly higher than that for the entire duration of the lunar flight phase of the Apollo program (between 100 and 150). Have you factored this into your baseline? No, you just took the MSL data and presented it as a constant GCR background level that should be present in all missions beyond LEO.

SPE's are directly proportional and the threat to personnel increases.

Yes, but they are discrete events and are detectable in the EM spectrum before the spacecraft gets hit by the particle flare. They are also directional. A massive flare from a sunspot on the limb of the sun as viewed from Earth won't send the most intense particle radiation anywhere near the spacecraft. So, the ground control team had time to detect a flare, decide if it was going to impact the spacecraft, and arrange some degree of protective action (which basically meant turning the spacecraft so the bulk of it was between the astronauts and the sun to provide maximum shielding).

So you believe the structure of the space craft is adequate shielding for the high energy proton flux of a large SPE?  Can you corroborate that with something other than your opinion?

Given that no such event occurred during any of the Apollo missions, the point's kind of moot, isn't it?

The cis-lunar radiation environment is not static.  It varies in ways that are largely predictable, and the Apollo missions were planned to fly when the odds of such an event were low.  Had a CME occurred during a mission, and if it were aimed in the direction of the Earth-Moon system, then no, the spacecraft mass likely would not have been adequate shielding. 

Do you cross the street when traffic's at its heaviest, or do you wait for a lull?