J. White calculates why Apollo craft could not have survived passage through the VABs

originally posted by: FoosM

originally posted by: Rob48

originally posted by: FoosM

originally posted by: Rob48
So, just how much radiation did skirting the edge of the high radiation zone deliver?

Now that you had some practice, do it for the flight where it goes through the heart of the belt.
Because that's on record, and you cant "skirt" around it.

OK I'll indulge you Foos, as I have some time to kill on a long journey.

Let's assume an absolute worst case scenario and pretend that Apollo 14 was launched straight along the geomagnetic equator, at the same speed as Apollo 11. That would take it right through the very strongest part of the inner belt. (And only the inner belt: this is important!)

If you refer back to that chart and imagine flattening the curved trajectory down to a straight line across the middle, you will see that it would take something between 20 and 30 minutes to cross the belt.

Again I will round up and call it 30 minutes.

Of this, the first half (15 mins) will be in the 1000 particle / cm² / sec zone. The remaining 15 minutes will be evenly split between the 100, 10 and 1 particle / cm² / sec zones (5 mins in each).

So let's work out the particle flux:

1000 zone:

1000 particles / cm² / sec x 15 min x 60 sec / min = 900,000 particles / cm².

100 zone:

100 particles / cm² / sec x 5 min x 60 sec / min = 30,000 particles / cm².

10 zone:

10 particles / cm² / sec x 5 min x 60 sec / min = 3,000 particles / cm².

1 zone:

1 particle / cm² / sec x 5 min x 60 sec / min = 300 particles / cm².

Total = 933,300 particles / cm².

Again assuming average of 200 MeV / particle:

Total energy flux = 933,300 particles / cm² x 200 MeV / particle = 186,660,000 MeV / cm².

Multiply up by astronaut body surface area:

186,660,000 MeV / cm² x 0.85 m² x 10,000 cm² / m² = 1.59 x 10^12 MeV.

Now, as we are passing through the centre of the belt we need to take into account the higher energy particles there. Here is a plot of the flux of >400 MeV particles. Note that it shows a smaller area than the plot before.

As this is a smaller area (only out to just over 2 Earth radii), the spacecraft would cross it in about 20 minutes. We can divide this as follows:

4 minutes at 100 particles / cm² / sec = 24,000 particles / cm²
4 minutes at 500 particles / cm² / sec = 120,000 particles / cm²
Another 4 minutes at 100 particles / cm² / sec = 24,000 particles / cm²
4 minutes at 10 particles / cm² / sec = 2,400 particles / cm²
4 minutes at 1 particle / cm² / sec = 240 particles / cm²

Total = 170,640 particles / cm².

Now remember, these will already have been included in the count of >100 MeV particles before, so I am actually double counting here making the worst-case scenario even worse!

Now let's go mad and take the energy of each particle as 1 GeV (1,000 MeV) here.

Total energy flux = 170,640 particles / cm² x 1,000 MeV / particle = 170,640,000 MeV / cm².

Multiply up by astronaut body surface area:

85,320,000 MeV / cm² x 0.85 m² x 10,000 cm² / m² = 1.45 x 10^12 MeV.

Add to the total from the >100 MeV particles before:

1.59 x 10^12 MeV + 1.45 x 10^12 MeV = 3.04 x 10^12 MeV

Convert to joules:

3.04 x 10^12 MeV x 1.6 x 10^-13 J / MeV = 0.486 J.

Convert to grays for a 75 kg man:

0.486 J / 75 kg = 0.0065 Gy.

Convert to rads:

0.0034 Gy x 100 rad / Gy = 0.65 rad.

Now multiply by two for a two-way trip.

Total = a whopping 1.3 rad, and that was with me overestimating the dose at almost every step!

For reference, the actual dose received by the Apollo 14 crew (including skirting the outer belt and traversing cis-lunar space) was 1.14 rad.

Obviously, A14 didn't go straight through the centre of the belt. It just went through more of it. The radiation was higher than expected because, as you mentioned, solar activity was higher.

Great, thank you for the effort you put into that.
But why stop there, why don't you go ahead and do the Electron belt too?

Two reasons:

1) I've spent enough time already and I need some sleep. Why don't you get your calculator out?

2) As you will know if you read Jarrah's source material, the beta radiation in the outer belt pales into insignificance compared to the protons of the inner belt:

beta radiation lacked the energy necessary to penetrate the spacecraft shielding. It was the highest energy protons of the inner radiation belt that posed the only real concern in trajectory planning and, as we have seen, Apollo was beyond this region in as little as ten minutes.

As you will see from your graphic, the outer electron belt is far less direction dependent.

I already calculated (when correcting Jarrah's original maths) for electron fluxes up to 2 x 10^6.

Look at the scale on your chart. It doesn't even go up to 10^7, so you are looking at, at most, a fivefold increase in electron flux even if you went straight along the equatorial plane.

Basically, electrons are not a big worry.

originally posted by: FoosM

originally posted by: Rob48
1000 zone:
1000 particles / cm² / sec x 15 min x 60 sec / min = 900,000 particles / cm².
100 zone:
100 particles / cm² / sec x 5 min x 60 sec / min = 30,000 particles / cm².
10 zone:
10 particles / cm² / sec x 5 min x 60 sec / min = 3,000 particles / cm².
1 zone:
1 particle / cm² / sec x 5 min x 60 sec / min = 300 particles / cm².
Total = 933,300 particles / cm².

By the way, where is the 10,000 particles per second zone?
I believe what many would call that the heart of the inner belt?

Check the energy level on that chart, Foos.

That begs the question, why didn't you use the AP8MAX chart?
Apollo's missions were during the Solar Max period.
So you should take that into account.

Well perhaps you could share your wisdom with the class: when do you find the highest level of trapped protons in the belts? At solar maximum or at solar minimum?

the radiation is likely the reason the apollo astronauts had a significantly higher rate of cataracts/glaucoma then the rest of us. the type of radiation you don't get in LEO. Thanks for bringing it up, it's one of the best cases for arguing that the apollo nauts did go to the moon.

originally posted by: Rob48

originally posted by: FoosM

originally posted by: Rob48
1000 zone:
1000 particles / cm² / sec x 15 min x 60 sec / min = 900,000 particles / cm².
100 zone:
100 particles / cm² / sec x 5 min x 60 sec / min = 30,000 particles / cm².
10 zone:
10 particles / cm² / sec x 5 min x 60 sec / min = 3,000 particles / cm².
1 zone:
1 particle / cm² / sec x 5 min x 60 sec / min = 300 particles / cm².
Total = 933,300 particles / cm².

By the way, where is the 10,000 particles per second zone?
I believe what many would call that the heart of the inner belt?

Check the energy level on that chart, Foos.

That begs the question, why didn't you use the AP8MAX chart?
Apollo's missions were during the Solar Max period.
So you should take that into account.

Well perhaps you could share your wisdom with the class: when do you find the highest level of trapped protons in the belts? At solar maximum or at solar minimum?

So, why didn't you use 10,000 particles per second?

originally posted by: syrinx high priest
the radiation is likely the reason the apollo astronauts had a significantly higher rate of cataracts/glaucoma then the rest of us. the type of radiation you don't get in LEO. Thanks for bringing it up, it's one of the best cases for arguing that the apollo nauts did go to the moon.

Ummm... OK.

In summary, astronauts on Apollo (5) and subsequent Skylab (37), space shuttle,2 and Mir (38) missions have observed light flashes that raise a concern for adverse tissue effects from single heavy-ion tracks (6). We report here preliminary results that indicate that low doses of space radiation increase the risk for cataracts,

emmrem.unh.edu...

high altitude and high inclination LEO missions can also see higher dose rates due to interaction with trapped particulate radiation within the Van Allen belts).

ntrs.nasa.gov...

originally posted by: FoosM

originally posted by: Rob48

originally posted by: FoosM

originally posted by: Rob48
1000 zone:
1000 particles / cm² / sec x 15 min x 60 sec / min = 900,000 particles / cm².
100 zone:
100 particles / cm² / sec x 5 min x 60 sec / min = 30,000 particles / cm².
10 zone:
10 particles / cm² / sec x 5 min x 60 sec / min = 3,000 particles / cm².
1 zone:
1 particle / cm² / sec x 5 min x 60 sec / min = 300 particles / cm².
Total = 933,300 particles / cm².

By the way, where is the 10,000 particles per second zone?
I believe what many would call that the heart of the inner belt?

Check the energy level on that chart, Foos.

That begs the question, why didn't you use the AP8MAX chart?
Apollo's missions were during the Solar Max period.
So you should take that into account.

Well perhaps you could share your wisdom with the class: when do you find the highest level of trapped protons in the belts? At solar maximum or at solar minimum?

So, why didn't you use 10,000 particles per second?

Did you read my reply? Check the energy level. Your chart shows the proton flux for >10 MeV. The one I used was for >100 MeV. Of course there will be more particles at lower energies, but we are only interested in high energy protons, because those below 100 MeV will be stopped by the shielding.

Do you know how far a 10 MeV proton will penetrate in aluminium? Answer: about 0.7 millimetres. For a 125 MeV proton this figure is 6.3 centimetres.

You were asking where NASA get their numbers for dose rates in the belts. Well, start here:

That dates from 1964, and so informed much of the Apollo programme. You may find some of the maths a bit chewy, but space flight does require quite a bit of that, I'm afraid.


PS Remind me: when do you find more protons in the inner belt? Under solar maximum or solar minimum conditions?
Still stumped? Here's a hint:

Another reason Jarrah is way off target on this video. He is focusing on electrons. Electrons are not even a major factor in plotting a course through the radiation belts, as the very source that he quoted from says.

I have now found the hard figures to show why this is so.

Remember, Jarrah took the electron flux figures for particles with energies greater than 0.5 MeV. These are in the range of about 10^6 - 10^7 (i.e. one to ten million) particles per cm² per second.

His first big blunder was to pluck a number out of thin air and claim that these electrons had a typical energy of 10 MeV.

Fortunately for me (and unfortunately for Jarrah) the data for the actual electron flux is available online. Like the AP-8 model which deals with proton flux, there is a model for electron flux, called (wait for it) AE-8.

You can enter the parameters you want and get a readout of the electron flux here: ccmc.gsfc.nasa.gov...



Across the top are the electron energies: 0.5, 2, 4, 5, 6 and 7 MeV (you can only do six values at a time so I skipped 1 and 3 MeV here).

Down the left are the distances in Earth radii across the outer belt.

As you can see, the flux of 0.5 MeV electrons varies from about 3 x 10^6 to 1 x 10^7 particles per cm² per second. (This is at solar maximum: unlike protons, electrons are at their peak under solar maximum.)

However, if you look at 2 MeV electrons, that drops to a peak of about 7 x 10^5, or 700,000.

For 4 MeV electrons, the peak flux is about 1.2 x 10^4, or about 12,000.

For 5 MeV, it is about 1,500. For 6 MeV, it is down to about 200.

And by the time we reach 7 MeV, there are just 3 particles per cm² per second at 3 Earth radii, and ZERO elsewhere.

So how on Earth does Jarrah justify using a flux of 1 to 2 million particles per cm² per second of 10 MeV electrons? Quite apart from his original calculations putting him out by a factor of several thousand, he is overestimating the electron flux by more than a million!

The flux drops off so rapidly at higher energies that the AE-8 model doesn't even bother going above 7 MeV.: there are so few particles that energetic that they are simply not worth bothering with.

And remember, these are the radiation belt models that are used when planning and operating satellite launches. They have been proven time and time again to work.

a reply to: Rob48

Could you translate that into a form of English that I actually understand?

originally posted by: seagull
a reply to: Rob48

Could you translate that into a form of English that I actually understand?

Basically Rob48 just proved, using math and correct sources about the belt, that in the video of the OP where Jarrah states that there is 1 to 2 million particles per centimeter squared is a bald face LIE.

The lower the MeV, the higher the particle flux density, the higher the MeV the lower it is.

Jarrah was claiming 1 to 2 million per cm^2 at 10 MeV were in reality by the time you get up to 7 MeV it's down to only 3 per cm^2.....going high drops it down to almost 0. Not millions like the video is claiming.

That was for electrons.

For the protons, Rob48 showed how far a proton can penetrate into aluminum (because of what the Apollo command modules were made of).

At an energy of 10 MeV, a proton can only penetrate aluminum up to 0.7 millimeters. However at higher energy levels, the proton can penetrate thicker aluminum, the example he gave is 125 MeV can get through 6.3 centimeter thick aluminum.

a reply to: seagull

Yes: Jarrah is talking out of the wrong orifice.

Closest analogy i can think of quickly:

Imagine you measured the speed of cars passing along your street. You find that there are 100 cars a day going more than 20mph.

What Jarrah is doing is basically taking that figure of 100 cars a day and then saying "Let's say all of those 100 cars are going at 100mph", and then doing lots of calculations to show how deadly your street is.


Or, to go back to the subject of radiation, in as close to laymans terms as I can get:

The energy level of the radiation is measured in units called MeV (mega electron volts).

Higher energy levels are (as you would expect) more harmful. Anything below about 5 or 6 MeV will be totally stopped by the shielding.

Jarrah took a figure for all particles with energies above 0.5 MeV and then said that each of those would have an average energy of 10 MeV.

In fact, there are virtually no particles with that energy.

originally posted by: Rob48

So how on Earth does Jarrah justify using a flux of 1 to 2 million particles per cm² per second of 10 MeV electrons? Quite apart from his original calculations putting him out by a factor of several thousand, he is overestimating the electron flux by more than a million!

i believe he uses 55MeV to come up with his mythical 500rads which foosm was harking on about earlier.. presumably because he found out that 10 MeV came back with survivable rads even with his faulty use of numbers.

and also doubling the rads/grays for leaving earth orbit and returning is also misleading..
considering they are out of the VAB for more than 7days the effects to any cells, if any, accumulated leaving the VAB would have recovered by the time they prepared for re-entry.

originally posted by: seagull
a reply to: Rob48

Could you translate that into a form of English that I actually understand?

basically when one number is high, the other number is low..

ie. if the energy (MeV) is high, the count (flux) is low.. and vice versa if the energy (MeV) is low, the count (flux) is high.. when i say count i mean the number of particles in a certain area in a certain amount of time.

and what Jarrah is doing is using high energy (MeV) and high count (flux) which is against nature.

originally posted by: Rob48

And remember, these are the radiation belt models that are used when planning and operating satellite launches. They have been proven time and time again to work.

Actually no, as I have posted before,
the Models are old, and outdated.

I wish that he would have produced that video about 70 years ago (ok, maybe on 16mm). He could have saved the American taxpayer many billions on false advertising.

originally posted by: FoosM

originally posted by: Rob48

And remember, these are the radiation belt models that are used when planning and operating satellite launches. They have been proven time and time again to work.

Actually no, as I have posted before,
the Models are old, and outdated.

Were they old and outdated when Apollo flew? Were they based on long term measurements from satellite data?

Try some reading if you want more of that data you don't think is out there:

ccmc.gsfc.nasa.gov...

ntrs.nasa.gov...

originally posted by: onebigmonkey

originally posted by: FoosM

originally posted by: Rob48

And remember, these are the radiation belt models that are used when planning and operating satellite launches. They have been proven time and time again to work.

Actually no, as I have posted before,
the Models are old, and outdated.

Were they old and outdated when Apollo flew? Were they based on long term measurements from satellite data?

Try some reading if you want more of that data you don't think is out there:

ccmc.gsfc.nasa.gov...

ntrs.nasa.gov...

Yes they were old and outdated.
They couldn't even measure the full extent of the VABs.
They didn't even know about CME's.

originally posted by: FoosM

originally posted by: Rob48

And remember, these are the radiation belt models that are used when planning and operating satellite launches. They have been proven time and time again to work.

Actually no, as I have posted before,
the Models are old, and outdated.

Funnily enough, the AE8 model actually overstated the high energy electron flux in the outer belt and has since been updated:

This study indicates that AE8 has excessive fluxes above 1 MeV beyond L=5.5, with the discrepancy being an order of magnitude at geosynchronous orbit. The high energy electrons peak in L about 0.5 L lower than indicated by AE8

So there are even fewer high energy electrons than the NASA model implied!

The IGE-2006 model which is quite a new one (for geostationary orbits) agrees pretty well with the revised AE-8 in the energy range we are looking at:



As you can see, both models have the flux going down to virtually zero before you hit 10 MeV (10,000 keV).

Is "the models are outdated" really the best response you can come up with?

Remember, the models are the exact same models that Jarrah was basing his fiasco of a video on. You didn't complain that he was using outdated models when you trumpeted it on here.

Or are they suddenly only so outdated now that you know they don't say Apollo was impossible?

Thanks, guys.

Where this sort of thing is concerned? I'm less than well versed.

originally posted by: Rob48


Is "the models are outdated" really the best response you can come up with?

Remember, the models are the exact same models that Jarrah was basing his fiasco of a video on. You didn't complain that he was using outdated models when you trumpeted it on here.

Why would I complain that JW was using those models? I don't think he or anyone else have been championing
those models, and if you watch the video, JW makes a point stating that different sources give different information. Those models are all we have had for a long time. And I have been pointing for quite a while they were outdated.

And yes, they are outdated. There is a reason why they have been working on AE9 and AP9.
I even read a report from a medical institution complaining that NASA does not share all their findings:

The Earth's Radiation Belts
The Earth's radiation belts (the Van Allen belts, discovered in 1958) consist of the inner and outer ion belts and the inner and outer electron belts. In general, the belts roughly conform to the geomagnetic field, peaking in altitude over the magnetic equator and projecting downward at high latitudes. Thus, at the magnetic poles, the belts are at their thinnest. Of interest, the belts come closest to Earth over a region known as the South Atlantic Anomaly (SAA); it is estimated that satellites and astronauts in LEO can accumulate 2% to 5% of their total radiation exposure from passage through this area. Indeed, trapped ions from the inner belt and electrons in the outer belt pose the greatest hazard to satellites and astronauts in LEO because these particles can obtain energies capable of penetrating matter to significant depths. Finally, it is important to note that the outer electron belt can vary in intensity over time as a function of the solar wind, with electron energies increasing by several orders of magnitude during an intense flux of electrons called a "highly relativistic electron (HRE) event." Highly relativistic electrons are, unfortunately, transient and difficult to predict. These are of concern to space travelers because electron energies during such events can exceed the energy threshold that is necessary to penetrate a space-suited astronaut during an extravehicular activity (EVA). Despite repeated requests, the study authors have been unable to confirm a specific number from NASA for the level of radiation protection in grams per cubic centimeter (the standard unit for radiation shielding) provided by their current space suit. (However, several experts associated with NASA have said that, for all practical purposes, the space suit provides no radiation shielding protection whatsoever.)

What Is Our Current State of Knowledge in Regard to Space Radiation Risks?
Despite over 45 years of manned spaceflight experience, detailed knowledge of the hazards of radiation exposure is severely lacking. Even the recommendations from the National Council on Radiation Protection & Measurements (NCRP) for an acceptable level of radiation exposure, which would increase NASA astronaut risk for cancer death by no more than 3% over the baseline risk, are extrapolated from observations of Hiroshima atomic bomb survivors and from those who have undergone radiation therapy for cancer or for medical diagnosis. It is important to note that these historical populations received acute radiation exposures that may be different from the predominance of chronic, low-level radiation exposure (interspersed with potential acute exposures) that would occur in space. Furthermore, other than the manned lunar landings, from which radiation exposure beyond LEO was also relatively short-term given the flight plans, we have little definitive data to base long-term human radiation exposure projections beyond LEO.

www.medscape.org...

See that, we don't know jack crap about the radiation environment. Unfortunately, because of the fakery surrounding Apollo, the reality of space travel has been obscured. As long as the lie is supported, we won't be able to travel to the moon, mars or anywhere else.

a reply to: FoosM

These are of concern to space travelers because electron energies during such events can exceed the energy threshold that is necessary to penetrate a space-suited astronaut during an extravehicular activity (EVA).

So, even these electrons are not hazardous so long as the astronauts don't forget to take a spaceship along with them.

You and reality will forever remain distant strangers, won't you?