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overrated
2003-Dec-05, 01:33 AM
I can scarcely remember the last time I posted on this board.

So I'm curious: Have any new lunar hoax theories been advanced lately? The few mentions I HAVE seen floating around on the Internet in the past few months have just been of the garden-variety, the-flag-shouldn't-wave species.

AstroSmurf
2003-Dec-05, 08:36 AM
So I'm curious: Have any new lunar hoax theories been advanced lately? The few mentions I HAVE seen floating around on the Internet in the past few months have just been of the garden-variety, the-flag-shouldn't-wave species.
New theories? Nah, same old, same old.

There are a few new arguments around now, though. Here are two from GLP:

The first is that Dr. Van Allen is on the payroll, and that the radiation levels are actually higher outside the Van Allen belts. For whatever reason, the guy who proposed this trusts SOHO to deliver reliable measurements, but I don't know enough to convert the figures from the detectors there to a "rem/day" figure.

http://umtof.umd.edu/pm

The second one is somewhat stranger (and harder to debunk), and claims that humans can't function normally without a surrounding magnetic field of a certain level. So far, he's provided absolutely no references, so it can be ignored as fluff for now.

And then there are of course the normal arguments that only require high-school physics to debunk, but those are of far less interest.

jrkeller
2003-Dec-05, 02:46 PM
There were a couple of interesting threads discussing this guy named Der Voron. My personal favorite was,

Moon hoax article 3/27/2003 (http://www.badastronomy.com/phpBB/viewtopic.php?t=5825)

especially BigJim's response to the alien engineered elephants


and the smokestack on the moon (non-Der Voron)

Weird object in NASA video (http://www.badastronomy.com/phpBB/viewtopic.php?t=7865)

JayUtah
2003-Dec-05, 03:19 PM
If I recall the SOHO argument correctly, the conspiracists take the yearly cumulatives and divide them by 365 to get some sort of average daily dosage. Then that dosage is multiplied by 12 or 13 or however many days some specific Apollo mission lasted in order to get an estimate of how much radiation the Apollo astronauts would have endured.

First and most obviously, the argument ignores the effect of spacecraft shielding.

Second and less obviously, the argument has a completely bogus statistical basis. The SOHO cumulatives include dosages from solar particle events, which are irrelevant to all Apollo missions except Apollo 16. These SPEs are discrete events that add to the cumulative, but don't affect the radiation environment in the long term, or for a sample of a small number of days.

The analogy I drew was this:

Imagine you sit on your front lawn every day for six months. During those six months it is sure to rain every so often and drench you. Now let's say you have a cumulative rain gauge that tells you how many inches of rain fell during those six months. You could take the total inches of rain and divide them by 180 days and arrive at an "average daily rainfall". So if you had 45 inches of rain, your "average" would be 0.25 inch per day.

If your nephew visits for a week, you could multiply seven days by the average and get 1.75 inches. But is this the same as saying your nephew was subjected to 1.75 inches of rain during his stay? What if it didn't rain at all during that week?

We have to keep in mind that most people -- conspiracists especially -- don't have a working knowledge of the types and sources of radiation in space, and how they behave qualitatively and quantitatively. This leads to all manner of misunderstanding and misinterpretation of data. The conspiracists generally aren't amenable to suggestions that their interpretation is invalid and offer protests to the effect, "How can you say this is wrong? This data comes straight from NASA!"

As for Der Voron, the guy is simply a maroon. I wish I knew a better way of saying it, but Bugs Bunny just has it all in hand. Voron has no technical background of any consequence, and he has an obsession with self-promotion. The only reason he's so widely published is that he hussles his stuff to every editor on the planet under multiple names. He even impersonated his own reviewer.

AstroSmurf
2003-Dec-05, 03:46 PM
Jay or whoever.

I agree about the interpretation, which is why I was looking for a technique to take the proton meter measurements for a suitable time period and derive some sort of useful dosage figure.

My guess is that you'd have to do something like ths:
Get the numeric detection data, basically the measured velocity of every single proton during a certain time period. Calculate the energy for those protons, and generate a histogram of # of protons vs energy for this time period. Check what kind of hull material the CSM had, and its absorbtion characteristics; Get an estimate of how much X-ray bremsstrahlung the protons generate, for the energy levels in question. Estimate how much of the X-ray radiation would be directed inside the crew compartment Finally, sum up the radiation for all of these protons to get a final dosage figure.
Looking at the list, getting an exact figure seems like a huge undertaking, but at least I might get a reasonable estimate. Seems I'd have to be lucky to end up within the same order of magnitude though.

Since this is a huge amount of work, are the original estimates available somewhere? I know they made measurements beforehand - which probes carried these detectors?

R.A.F.
2003-Dec-05, 03:51 PM
The SOHO cumulatives include dosages from solar particle events, which are irrelevant to all Apollo missions except Apollo 16.

OK, once again I'm forced to show my ignorance concerning Apollo. So why was Apollo 16 different? (I assume there must have been a "Solar event" during the mission.)


As for Der Voron, the guy is simply a maroon. I wish I knew a better way of saying it, but Bugs Bunny just has it all in hand.

I, too, have used maroon as a form of "insult". It sounds so much better than "idiot" and the way Bugs says it...just says it all.

BTW, Jay, your "rainfall" analogy is perfect.

JayUtah
2003-Dec-05, 05:13 PM
So why was Apollo 16 different? (I assume there must have been a "Solar event" during the mission.)

Yep, a medium-sized one as far as events during those few years go. Had the crew been on the lunar surface at the time, the exposure would have been about 3 rem. As it was they were in the command module with a skin dose of about 200 millirem -- say, a hefty chest x-ray.

I, too, have used maroon as a form of "insult".

Well, insults are forbidden here, and for good reason. I think of a "maroon" as somone comically "in over his head". Der Voron and Wile E. Coyote have a lot in common. Each thinks he has it all figured out, but the plan never survives contact with the opponent.

Beginning with Apollo 7 and ending with Apollo 17 there were about 22 solar events of significant magnitude, and only one of them (August 1972) had a fatal potential. All the rest would have produced in-suit skin dosages of less than 100 rem -- worrying but not fatal. When the conspiracists try to tell you figures of 1,400 flares or 15 flares per day or scary numbers like that, they're counting every flicker, burp, and hiccup that registered on our instruments.

BTW, Jay, your "rainfall" analogy is perfect.

A lot of radiation exposure concepts lend themselves well to analogies that involve getting wet.

R.A.F.
2003-Dec-05, 05:22 PM
I think of a "maroon" as somone comically "in over his head".

I concede to your interpretation.

JayUtah
2003-Dec-05, 05:56 PM
I agree about the interpretation, which is why I was looking for a technique...

You're on the right track, but the execution of the method quickly gets ugly.

For every point in your environment you have two dimensions of data: flux and energy. Particle energy is measured in electron volts and can be equated, for each type of particle, to penetration depth in various common materials. This is the information most useful to engineers. Flux is simply the number particles passing through a unit area per second. We typically divide energies into categories, say orders of magnitude of energy. Then we can create 3D flux maps of the environment for each source category. The particles in each energy category are assumed to have similar biological and engineering effects even though that's a linear approximation to a continuous effect.

Check what kind of hull material the CSM had, and its absorbtion characteristics

In theory, simple. In practice, difficult. Most real-world designs incorporate materials and structures that have different radiation characteristics depending on the exposure aspect. Radiation is directional. That means the orientation of the structure with respect to the source affects the measured dosage inside the structure. And the measured dosage will not be the same at every point.

Get an estimate of how much X-ray bremsstrahlung the protons generate, for the energy levels in question. etc.,

Simple in theory, but nigh unto impossible in practice.

In theory, for zero-aspect irradiation and plate material, the secondary radiation measured at some wavelength at some fixed distance inside the structure follows a complex functional behavior that depends on the atomic weight and thickness of the material.

Imagine material so thin that it has no practical effect on incoming particles. There are no collisions, therefore no secondary radiation. Now increase the thickness gradually. More particles will be absorbed as thickness increases, and therefore the amount of secondary radiation increases. But this is true only up to a point. As you further increase the material thickness, all the incoming particles are absorbed. And what's more, they are absorbed in the outer portion of the shield material. The secondary radiation thus produced is absorbed by the inner layers of shielding, so as thickness increases the secondary radiation measured inside the structure decreases after an initial increase.

If you graph total radiation (both primary and secondary) as a function of shield thickness, the graph rises, reaches a maximum, and then falls off to zero, all in quadratic fashion.

But of course the CM skin thickness varied because its primary role was structural and thermal. The skin is thinner near the apex and thicker near the base. And the crew compartment was nearer to the base than to the apex.

Materials such as the fibrous insulation (i.e., felt) between the two skins will serve to absorb particles without producing secondary radiation. This is why materials such as water and polyethylene -- dense materials with lots of light elements in them -- are frequently used to shield against this type of radiation.

Looking at the list, getting an exact figure seems like a huge undertaking

Huge enough that nobody does it this way. You do a first-order approximation in the design phase and then test empirically.

Since this is a huge amount of work, are the original estimates available somewhere?

I could probably dig up enough raw data to facilitate a first-order approximation. I don't have any references to any that were done at the time.

I know they made measurements beforehand - which probes carried these detectors?

Everything from Explorer I to Apollo 8, plus sounding rockets launched by many non-NASA and non-American groups.

AstroSmurf
2003-Dec-05, 11:07 PM
For every point in your environment you have two dimensions of data: flux and energy. (etc) I know; I tried to make that clear in my post, though my terminology may be a bit off. I don't work with this stuff, plus that English is my second language, so I might have come off as slightly naive about this. I knew it would be a tall order, but didn't realise before I wrote the last post just how tall it would be. It seems some serious finite element analysis would be required, at the very minimum.

Ahem. Anyway, thanks for the essay. Some of the stuff I knew, but some was news to me (mostly the Apollo-specific stuff).

My idea was to get a first-order approximation; I would be very happy to end up within an order of magnitude of the correct answer.

Put simply, when I see someone state a figure like "0.2 rem/day", I would like to know how this figure was arrived at. Is it even possible to determine this from direct proton energy measurements, or do you have to send up a dosimeter first?


I could probably dig up enough raw data to facilitate a first-order approximation. I don't have any references to any that were done at the time.
Don't put down a big effort on this unless you feel like it; it would be nice for me to know, and it might be helpful to have on hand if I find a HB to debate with (I know of only one in my city, and I don't know him personally).