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Post by LunarOrbit on Nov 15, 2009 22:52:39 GMT -4
fm, imagine it this way...
You're standing in front of a wall and on the other side is a prize worth $10 million. If you can get to the prize in under 5 minutes it's yours. The wall extends 10km to either side of you, it's half a meter thick, and 1 meter high. There are no doors or windows in the wall.
How will you get to the prize? Walk 20km around the wall, or maybe tunnel through it? Those are the only options if you only think in two dimensions... but what about the third? A-ha! You can climb OVER the wall! Now the length and thickness of the wall don't matter, only the height does and an average sized adult can surely climb a 1 meter high wall.
My point is that the span of the Van Allen Belt isn't an issue if you think in three dimensions. True, the spacecraft couldn't avoid the belt entirely, but it was (in combination with the shielding) enough to significantly reduce the astronauts' radiation exposure.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Nov 16, 2009 4:23:07 GMT -4
I'm making good progress on my Apollo 11 trajectory project. I've got the orbital elements figured out and a method for calculating the coordinates. Now I just have to set up all the equations in a spreadsheet and plot some views of what it looks like. I'm putting it all in an web page on my site, so I'll post a link to it here when I'm finished.
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Post by drewid on Nov 16, 2009 4:46:38 GMT -4
fm. Are you aware of the different composition of the inner and outer belts?
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Post by Jason Thompson on Nov 16, 2009 5:05:16 GMT -4
your VABs also seem rather small in comparison to the Earth. What did you exactly base your scale on? I based them on the particle intensity maps provided on Wikipedia, which are scanned from original texts on the belts. They were measured out to between 7 and ten Earth radii. Measure the drawing on the screen if you want. The shading is a rough representation of the intensity as shown on those contour maps, one of which you even provided in an earlier post.
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Post by JayUtah on Nov 16, 2009 9:56:11 GMT -4
Its quite simple actually.No, it isn't. You just keep trying to simplify it because that's the only way you can appear to make headway. There are no sharp boundaries to the Van Allen belts; they just fade away gradually into nothing. When one establishes a boundary for a certain purpose, one selects the degree of intensity one considered significant. The "boundary" then corresponds to the isosurfaces for that given intensity. You've been asked to tell us what intensity you believe to be significant and why. You've consistently ignored that request. The Van Allen belts change shape in response to solar influx and to natural variations and interactions in Earth's magnetic field. The standard models capture this behavior, which transcends static sketches. When one understands the complex nature of the trapped radiation environment, one understands that "it isn't simple," and that your question really has no meaning. Maybe you do, because when I look at your sketch, your VABs also seem rather small in comparison to the Earth.Make your own 3D model then. In case it's not clear, we're all rather tired of your tedious nit-picking that skips your gigantic lapses in understanding. Put up or shut up.
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Post by JayUtah on Nov 16, 2009 10:30:14 GMT -4
Your drawings revealed that the VABs where not bypassed.You are the one demanding the drawings. Real space scientists don't use them or need them. Drawings must incorporate some degree of simplification in order to make them comprehensible. You stubbornly resist any other form of explanation. Whether one uses a pencil, a donut, or a computer model, the shape of the Van Allen belts cannot be represented in full accuracy because the trapped radiation environment does not have static or well-defined boundaries. NASA says they weren't bypassed.False. You cite one anonymous page that's riddled with this and other errors. You stubbornly resist being directed to more official, accurate sources. You cling desperately to the one item you believe supports your view while ignoring reams of evidence to the contrary. And I define bypass as not going through them at all.You can make up whatever you want. But you can't force NASA or the rest of the world to accept your redefinitions. So what did you mean by bypass?As it has been explained at length, the intensity of the Van Allen belts varies by several orders of magnitude depending on latitude, longitude, and geodetic altitude. As it has been explained at length, the spacecraft did not avoid the Van Allen belts entirely, but rather skirted the edge of the belts where the exposure was minimal. The spacecraft shielding was able to to withstand this intensity. No one has ever claimed that the spacecraft avoided the Van Allen belts entirely -- i.e., so that there was no increase in exposure over the nominal orbital or cislunar baseline.
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Post by JayUtah on Nov 16, 2009 11:17:54 GMT -4
But before we do, here is your basic Geiger Counter:No. That is one cheaply made Geiger counter. www.quicktest.co.uk/geiger_counter.htmPlease note where the author of this page clearly disclaims his description as "non-technical." There is much more to operating a Geiger counter than this page implies. Have you, fm, ever personally operated a Geiger counter and interpreted the results? "- 700: Geiger counter overloads and gives continuous alarm - extreme caution!"Yes, that's where this one counter overloads. Real commercial ones typically register 10,000 cpm or more. And counts per minute is not by itself a useful measure of radiological or biological effect. Once again you've Googled up something highly oversimplified and are trying to pretend that means you understand radiation and how to measure it. Your article doesn't cover counter calibration, which is probably the most important step. And it completely ignores the first rule of radiation measurement, which is to know what kind of radiation you're measuring.So at this point, he doesn't even know about the OUTER BELT.Wrong. Van Allen's landmark paper in Nature clearly describes and illustrates both Van Allen belts. Wow.... 35.000 cps. And 700 is already extreme caution?No. Your non-technical paper is leading you to draw erroneous conclusions. Counts per minute is valid only for a specific model of counter, and only when properly calibrated. No number of counts per minute is automatically dangerous, especially when the source of the radiation is not exactly known. How do you suppose they would label 35.000 cps on a Geiger CounterTypically by setting the multiplier to X1000 and reading 35 off the needle. Van Allen figured that the radiation level inside the satellite might reach about 0.06 roentgens per hour.But you leave out the part where this estimation was based on (1) assumptions of the shield values of the spacecraft and (2) assumptions of the nature of the source of radiation he was measuring. Neither of those assumptions holds for Apollo nor stood the test of time. They were his best guesses decades ago. Now we know better. He didnt say add aluminum shielding. He states LEAD.So what? Lead does work, but it's certainly not the best material to use. Van Allen is not a subject-matter expert in spacecraft design. Van Allen didn't mention HDPE, but that's the material we use now. He didn't mention water, but that has been the most common shield material since the 1940s. He didn't mention aluminum, but ESA's tabular figures for shielding use aluminum as the reference material. 1. One beltNo, that's you putting words into Van Allen's mouth. 2. Lead shieldingLead will work. Other materials work better. Van Allen isn't a spacecraft designer, so his speculation on shielding is not necessarily the best knowledge the world has. 3. Radiation types unknown ( lead is not effective against all types of radiation )True. James Van Allen did not have the means to determine the composition of the trapped radiation when he published his initial paper. That does not mean we don't now understand them. You don't seem to understand that our knowledge -- and that includes Van Allen's personal knowledge -- increased over the decades. It became more sophisticated and more accurate. Why you keep citing decades-old research is beyond me. 4. 5 hours max doseGiven one set of assumptions. 5. 20 minute trip in the beltGiven one set of assumptions. "All manned space flight attempts must steer clear of these two belts of radiation until adequate means of safeguarding the astronauts has been developed"
So what happened here?What happened here is that Apollo steered clear of the Van Allen belts, just as James Van Allen suggested they do, and just as James Van Allen helped them do. Lead not good enough?Nope, aluminum is superior. Trip not fast enough?Your claim is that the trip wasn't fast enough. But you won't give any evidence of that, so we ignore your claim. Roentgen's too high?No. Between Van Allen's initial research and Apollo's first flights, much research was done on the Van Allen belts, including the effectiveness of shielding. Other dangerous radiation types discovered?Nope. In fact, it was discovered that particle energies were far lower than feared except in certain narrow "cores" through the belts. "The strongest radiation particles of all are gamma particles."Nope. "This is the most common type of radiation in space."Nope. Dense like.... lead?Yes, lead, water, and concrete are typically shielding materials for gamma rays. Unfortunately contrary to your article, gamma rays are not the most prevalent form of radiation in space, and certainly not in cislunar space where charged particles dominate. Aluminum is far superior than the equivalent mass of lead because the secondary radiation that is produced is of a longer and less hazardous wavelength. Further, aluminum has structural properties that let the spacecraft's structure also be its principal shielding. Really, fm, spacecraft design is today a commercial activity. Textbooks on the subject are not hard to find, as are examples of working spacecraft. Do you really think you can Google up a few facts and spread your ignorance over them liberally and pretend that this qualifies you to question the validity of a mission that all the relevant experts accept as authentic? Gamma particles! LOL! Just how much ignorance are you prepared to display before giving up this charade?
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Post by dwight on Nov 16, 2009 12:18:15 GMT -4
I always thought the radiation belts resembled out of focus metallic cloth which also made noises like analog tape echo whenever a spacraft flew through them. At least that is what the on board cameras of the jupiter 2 lead me to believe.
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Post by JayUtah on Nov 16, 2009 13:19:26 GMT -4
Scientists classify solar flares into 3 categories.No, scientists use those categories for electromagnetic events. "Solar flare" is an inexact term used in popular literature, and covers many kinds of solar phenomena. Conspiracy theorists habitually confuse them all. Real space scientists do not. Solar flares produce electromagnetic radiation. This radiation can reach the earth within 8 minutes.Electromagnetic radiation travels at the speed of light, yes. By definition. Not all flares are significant x-ray flares. Most that we record emit in the visible or radio wavelengths. The hydrogen-alpha band is a popular wavelength for observation and solar weather forecasting. Both soft and hard x-rays interact with the upper atmosphere to produce effects such as blackouts or radio interference. That doesn't mean they also have a biological effect. The main rays that are most harmful are x-rays and gamma-rays since they have the most energy.The most energy of what? Of the wavelengths represented in the flare, and of normal solar emission. "High-energy" does not automatically mean biologically significant. Please interpret for us the following spectral and intensity analysis. hesperia.gsfc.nasa.gov/hessi/images/comp_spec.gifPlease also explain how the ISS astronauts cope, since the Van Allen belts offer absolutely no protection against these solar electromagnetic effects. I know how they cope, and so does NASA, and so do most of the regular posters here. But the fact that you bring it up suggests you do not know. And that's what I expect from someone who talks about gamma "particles." Solar flares also have coronal mass ejections (CME's)...No. Some electromagnetic events are accompanied by a particle event. Most are not. Biologically significant particle events (ca. energies of 1 MeV and flux of 10,000 per square centimeter) occur on average about 6 times per year. Currently, Solar Flares are impossible to predict...That depends on how you define prediction. 1. they cant predict when they come. 2. It takes 8 minutes to reach the Earth.No. No one can say when the next CME will occur. But based on solar observation we can determine the likelihood that one will occur in the next few days. And when one does occur, the electromagnetic components arrive at the speed of light and signal us perhaps to prepare for any particles, which may arrive generally hours or days hence. How in the world can you say that there is time to react?Because we understand the true nature of the phenomenon, not the cartoon version gleaned from frantic Googling. Another thing, why do I get the impression that some people on this forum do not want these questions to be solved?Why do you think your repeated displays of colossal ignorance constitute any effort to solve a problem, or the legitimate expression of a problem? The only ones who seem to have difficulty with these concepts are conspiracy theorists, who display an obvious bias and none of whom seems to have stayed awake in science class. Apollo engineering and trajectory design are required reading in colleges today. You once suggested that all scientists believe as you do. But you backpedaled away from that as soon as you were asked to name actual names. Yes, you sense reluctance from people here. We are reluctant to jump through your contrived hoops that derive largely from your inability or unwillingness to understand the relevant phenomena. Given your track record, it is unlikely that any effort undertaken here will actually change your mind. You have made outrageous claims for which you have provided no proof whatsoever, beyond your inability to to understand how other people achieved great things. I think both sides, hoaxers and non-hoaxers might be benefiting... dare I say - financially - by keeping these debates going.If you think you can prove that I get paid to do this, go right ahead. The web site that I maintain at my own expense and in my spare time costs me about $300 per year. Bart Sibrel, on the other hand, owns a company AFTH LLC that boasts six-figure revenues from selling his Apollo hoax hogwash. Ralph Rene's reprint is currently selling for $50 for just under 200 pages. David Percy still sells his book and video at substantial cost. So please, if you're going to follow the money, pay attention to the evidence for who's really grubbing for it.
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Post by drewid on Nov 16, 2009 17:52:14 GMT -4
I have some questions for you fm
Why are the different compositions of the inner and outer belts important when considering shielding?
What are the thickness penetrations of electrons or protons through aluminium, and at what energy levels?
It's pretty easy to find these figures.
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Post by fm on Nov 17, 2009 12:47:21 GMT -4
I have some questions for you fm Why are the different compositions of the inner and outer belts important when considering shielding? What are the thickness penetrations of electrons or protons through aluminium, and at what energy levels? It's pretty easy to find these figures. So why are you asking me? Do these questions have anything to do with with finding out how long it took Apollo missions to go through the VABs? Because thats all I have been trying to get answered. All these other questions are not relevant to me until I know how fast those spaceships went through the belts. Because there is a difference if it took them minutes to go through vrs hours. So Im really curious to see what Bob B. will have for us when he is finished. Or maybe you might finish yours?
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Post by JayUtah on Nov 17, 2009 13:03:41 GMT -4
So why are you asking me?Because the validity of your questions depends upon your understanding of the physical phenomena at work. You pretend to style yourself as a watchdog, making sure all the facts about Apollo line up. But in most cases the premises to your questions are purely ignorant. You ask questions that presume your understanding of the physical world is correct. In most cases it is not. Therefore it is appropriate to determine your level of understanding. Do these questions have anything to do with with finding out how long it took Apollo missions to go through the VABs?Yes. They are relevant because they address the intensity of the environment, which in turn addresses the potential duration of a manned spacecraft inside that environment. As has been repeatedly explained to you, the only meaningful concept of "boundary" in the Van Allen belts is subjective and highly variable and depends on your answer to those questions. Because thats all I have been trying to get answered.False. You have asserted that Apollo took too long to pass through the trapped radiation than was safe. But you have provided absolutely no evidence to support that claim. Instead you have, in troll fashion, established a bunch of meaningless hoops for others to jump through while accepting absolutely no responsibility of any kind to support your claims or even to answer questions about them. All these other questions are not relevant to me...Evasion noted. You whine about not having your questions answered. You completely ignore the repeated explanations about why your questions cannot be answered until you provide more information. So Im really curious to see what Bob B. will have for us when he is finished. Or maybe you might finish yours?Or maybe you will finally answer a question.
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Post by Jason Thompson on Nov 17, 2009 13:18:40 GMT -4
So why are you asking me? Because your ability or willingness to answer is important to this whole discussion. You have demonstrated NO understanding whatsoever as yet, apart from some quick googling that has not turned up the best sources for your arguments. Yes, they do, because defining how long it took to go through them depends on defining a boundary. Since there is no hard boundary to the belts and they are in constant flux due to solar activity anyway, the answers to these questions will assist in defining a boundary. It matters because you can define a boundary in terms of the regions of most intense radiaiton, in which case Apollo missed them entirely, or in terms of a less intense level of radiation, in which case Apollo might just skim the very edge, or an even lower level, in which case Apollo could have spent a long time inside. And that's all we have been trying to answer, but you stubbornly refuse to accept that reality is not conforming to your limited understanding and doesn't work the way you insist we define it. All those questions are crucial. The spacecraft was coasting, which means its speed was constantly changing due to gravity. How fast it went through depends on where you draw the line of the belt boundary. A belt 200 km wide would be passed through much quicker at 2 Earth radii than it would be at 8 Earth radii, for example. Answer one question: Do you now grasp the idea that the inclination of orbits is important and can mean that altitude is not the sole factor in determining whether or not a spacecraft is within the belts, or how intense the radiation at that altitude is?
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Post by fm on Nov 17, 2009 13:44:02 GMT -4
fm, imagine it this way... You're standing in front of a wall and on the other side is a prize worth $10 million. If you can get to the prize in under 5 minutes it's yours. The wall extends 10km to either side of you, it's half a meter thick, and 1 meter high. There are no doors or windows in the wall. How will you get to the prize? Walk 20km around the wall, or maybe tunnel through it? Those are the only options if you only think in two dimensions... but what about the third? A-ha! You can climb OVER the wall! Now the length and thickness of the wall don't matter, only the height does and an average sized adult can surely climb a 1 meter high wall. My point is that the span of the Van Allen Belt isn't an issue if you think in three dimensions. True, the spacecraft couldn't avoid the belt entirely, but it was (in combination with the shielding) enough to significantly reduce the astronauts' radiation exposure. What if the wall is electrified, and it completely surrounds you. Except you can climb over it or but its 2 meters high and 10 meters thick.... but thats not all. Your the size of an ant. You think that makes a difference whether or not you could think in three dimensions?
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Post by JayUtah on Nov 17, 2009 13:58:47 GMT -4
What if the wall is electrified, and it completely surrounds you. Except you can climb over it or but its 2 meters high and 10 meters thick.... but thats not all. Your the size of an ant.Please explain why your answer is relevant to your questions regarding the Van Allen belts.
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