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Post by zvezdichko on Nov 14, 2009 8:47:36 GMT -4
Oh... a question about radiation? Sorry. As a biologist I simply cannot be convinced that the nature of radiation in Van Allen belts could kill astronauts in an Apollo capsule - given the specifics of trajectory, time of exposure, etc, etc...
Solar flares are really dangerous, but there is time to react.
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Post by Jason Thompson on Nov 14, 2009 11:22:42 GMT -4
the point where Apollo was on the correct plane of the moon for orbit. You're still not getting it, and this is a meaningless statement. Apollo never had to be on the same plane as the Moon' orbit. The TLI orbit plane was the correct plane to intersect the plane of the moon's orbit. Not required, since the planes are apparent from the visuals. The orbit is a plane, the belts are in a plane. You don't need a line through a plane to represent it in a 3D image. The image is better than the plane drawing I made. Because NASA has provided all the information about the mission it needs to. It is not NASA's responsibility to spoon-feed people who don't understand orbits and radiation and so on.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Nov 14, 2009 12:29:01 GMT -4
I take it the curve of the ellispse in that diagram is seen from the normal, perpendicular to the plane of the orbit? Correct. It'd be great to get the first four hours of teh curve filled in a bit more. I don't want to spend much more time on that particular simulation because I think it is too limited. I intend to take a new approach to the problem, which, if successful, I'll make a presentation later. Nonetheless, I can probably provide a table of data for the first four hours using a smaller time increment. You can then use that information in whatever way you want. I'm going to have to resurrect my old data, so I need a little time to get it together. What are the differences on trajectory in the later missions. I know 17 didn't use a FRT for instance, would the TLI stage have looked substantially different, or would it have only become apparent later in the curve? The free-return trajectory shown is just a sample that doesn't represent any particular mission. In fact, several simplifications were made, such as making the spacecraft and lunar orbits coplanar. You might also be interested in taking a look at my simulation of a Lunar Hybrid Profile.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Nov 14, 2009 16:27:28 GMT -4
Below is the first four hours of the "Free Return" simulation in 10-minute increments. X and Y are the coordinates of the spacecraft. The origin is the center of Earth and the X axis is the major axis of the orbit ellipse. The Y axis is at a right angle to the X axis and lies in the plane of the orbit. The Z axis is normal to the plane of the orbit, therefore Z=0 at all times. R is the length of the radius vector, i.e. the line connecting the center of Earth to the spacecraft. Vx and Vy is the spacecraft velocity in the X and Y directions, and V is the total velocity. T (min) | X (m) | Y (m) | R (m) | Vx (m/s) | Vy (m/s) | V (m/s) | 0 | -6,563,140 | 0 | 6,563,140 | 0.0 | -10943.2 | 10943.2 | 10 | -5,114,802 | -6,114,763 | 7,971,921 | 4256.4 | -8955.3 | 9915.4 | 20 | -2,105,177 | -10,692,936 | 10,898,195 | 5445.2 | -6467.1 | 8454.2 | 30 | 1,210,902 | -14,070,071 | 14,122,082 | 5529.4 | -4919.5 | 7401.1 | 40 | 4,482,875 | -16,712,293 | 17,303,089 | 5360.5 | -3957.8 | 6663.2 | 50 | 7,635,036 | -18,882,486 | 20,367,672 | 5145.4 | -3315.4 | 6121.0 | 60 | 10,658,641 | -20,727,391 | 23,307,325 | 4935.8 | -2858.0 | 5703.5 | 70 | 13,561,666 | -22,334,889 | 26,129,793 | 4744.2 | -2515.6 | 5369.9 | 80 | 16,355,577 | -23,761,295 | 28,846,213 | 4572.0 | -2249.4 | 5095.4 | 90 | 19,051,610 | -25,044,761 | 31,467,505 | 4417.6 | -2036.2 | 4864.3 | 100 | 21,659,801 | -26,212,316 | 34,003,419 | 4278.8 | -1861.1 | 4666.0 | 110 | 24,188,844 | -27,283,816 | 36,462,402 | 4153.4 | -1714.7 | 4493.4 | 120 | 26,646,208 | -28,274,287 | 38,851,714 | 4039.6 | -1590.1 | 4341.3 | 130 | 29,038,307 | -29,195,387 | 41,177,590 | 3935.6 | -1482.8 | 4205.7 | 140 | 31,370,675 | -30,056,348 | 43,445,406 | 3840.3 | -1389.2 | 4083.8 | 150 | 33,648,107 | -30,864,614 | 45,659,824 | 3752.3 | -1306.7 | 3973.4 | 160 | 35,874,784 | -31,626,278 | 47,824,906 | 3670.9 | -1233.5 | 3872.6 | 170 | 38,054,373 | -32,346,399 | 49,944,218 | 3595.3 | -1168.0 | 3780.2 | 180 | 40,190,110 | -33,029,222 | 52,020,904 | 3524.7 | -1109.0 | 3695.0 | 190 | 42,284,866 | -33,678,346 | 54,057,755 | 3458.6 | -1055.6 | 3616.1 | 200 | 44,341,199 | -34,296,854 | 56,057,258 | 3396.5 | -1006.9 | 3542.6 | 210 | 46,361,403 | -34,887,408 | 58,021,642 | 3338.1 | -962.3 | 3474.0 | 220 | 48,347,542 | -35,452,322 | 59,952,914 | 3282.9 | -921.3 | 3409.7 | 230 | 50,301,483 | -35,993,620 | 61,852,889 | 3230.7 | -883.5 | 3349.3 | 240 | 52,224,919 | -36,513,087 | 63,723,212 | 3181.2 | -848.5 | 3292.4 |
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Post by drewid on Nov 14, 2009 18:22:50 GMT -4
Nice one, I'll get onto that.
Has anyone got a near C ship hiding in the garage? I could do with a couple more days this week.
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Post by randombloke on Nov 14, 2009 19:54:49 GMT -4
I did, but it was lost during testing. And when I say "lost" I mean "we can't find it" - see, it was set to cut drive 2 minutes into the test flight, but unfortunately the timer was on-board. Best we figure it's our past Centauri and still accelerating...
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Post by fm on Nov 14, 2009 20:11:42 GMT -4
1) Here's from the wiki viewpoint. 2) add the hotter bits of the belts OMG LOOKIT RADIATION (that was sarcasm by the way). 3) And the extent of the belts, the less dangerous bits. So lets look at that from another angle 1) Misses the hot section completely. 2) Just skims through the edges of the less dangerous bits. 3) Cut away and materials changed to make it clearer. Now I have to ask drewid.... your sketch of the VAB is that only the inner belt that you drew in there? Or both VABs? Because the size only looks to be about 2 Earth radii Which is about the size of the Inner Belt: The inner Van Allen Belt extends from an altitude of 700–10,000 km (0.1 to 1.5 Earth radii)Lets not forget: The large outer radiation belt extends from an altitude of about three to ten Earth radii. and its greatest intensity is usually around 4-5 RESo the VABs compared to the Earth should look something like A scale drawing, showing the World from above the North Pole, in conventional, Western teaching. Here is another... with inclination Here is one that shows how tall and wide it is. about 3.5 to 4 radii tall and 9 to 10 wide. I think those pictures are a good representation, right? zvezdichko : Oh... a question about radiation? Sorry. As a biologist I simply cannot be convinced that the nature of radiation in Van Allen belts could kill astronauts in an Apollo capsule - given the specifics of trajectory, time of exposure, etc, etc... Solar flares are really dangerous, but there is time to react. Really? How? Scientists classify solar flares into 3 categories. There can be X-Class, M-Class and C-Class flares. X-Class flares - These flares are very large. They are major events that can set off long-lasting radiation storms and planet-wide radio blackouts. M-Class Flares - They flares are medium sized. These cause brief radio blackouts, which affect the polar regions of the earth. C-Class Flares - These flares are the smallest of the three classes and have few noticeable consequences here on earth.Solar flares produce electromagnetic radiation. This radiation can reach the earth within 8 minutes. The main rays that are most harmful are x-rays and gamma-rays since they have the most energy. Solar flares also have coronal mass ejections (CME's) that result in the ejection of highly energetic ions, electrons and protons. Solar Flares can cause a lot of serious problems for airline pilots due to these kinds of radiation. Currently, Solar Flares are impossible to predict and the most number that can occur in any given year would only be a few.So, 1. they cant predict when they come. 2. It takes 8 minutes to reach the Earth. How in the world can you say that there is time to react? Another thing, why do I get the impression that some people on this forum do not want these questions to be solved? I think both sides, hoaxers and non-hoaxers might be benefiting... dare I say - financially - by keeping these debates going.
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Post by homobibiens on Nov 14, 2009 20:52:43 GMT -4
it was set to cut drive 2 minutes into the test flight, but unfortunately the timer was on-board. Relativity jokes ;D
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Post by randombloke on Nov 14, 2009 22:02:19 GMT -4
fm: "Blah blah blah "flares can't be predicted" blah blah" citation? Date of citation? As I recall, flares were at least somewhat predictable, with a range of a couple of days, back when Apollo was flying. "A few days" being plenty sufficient for a three day mission. It is of course wildly insufficient for an extended duration mission to Mars for instance, which is why a new set of radiation studies is being done on the interplanetary environment. Also, "unpredictable" is not the same as "unobservable" - flare maxima are preceded by visible surface activity on the Sun, from which approximate intensity and primary vectors can be derived. On such a warning, astronauts can be ordered into their radiation shelter. Of course, this is a misdirection on your part as flares have very little to do with VAB radiation, which is particulate in nature and derived primarily from the solar wind, a separate phenomenon. @ Homo bibiens: thankyou, thankyou, I'll be here all week; try the fish! And tip your servers!
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Post by JayUtah on Nov 14, 2009 22:26:35 GMT -4
Well, fm, you clearly don't understand the difference among the various inclinations we've discussed. Your diagram gives inclination relative to the geomagnetic axis. Now I bet you wish you hadn't ignored Jason's diagram. He understands; you do not. The current models are AP-8 and AE-8. Not some simplified moldy diagram.
You have still provided zero evidence for the claim that the Apollo spacecraft spent more time in the Van Allen belts than generally believed. And you clearly lack the means to do so.
Naturally you're trying to change the subject to solar activity. And I can see that you're the latest in a long line of people who think they can Google their way to erudition but who can't keep straight basic facts like the difference between x-ray events and particle events. "Solar flare" is overused in the popular literature but not in the technical literature.
And so once again, fm, you're trying to parley your ignorant interpretations and simplifications and misunderstandings into the vague notion that there's something wrong. You can't make facts fit your simpleton understanding so you attack the facts.
Why do you think these problems haven't already been solved? They've been solved. The issue here is trying to express those solutions such that your stubborn mind accepts them in whatever capricious form you've selected for today. I'm sure you're under the delusion that you're being some kind of watchdog, keeping everyone honest. But in fact this is just a painful exercise in correcting your copious ignorance and your determination to retain possession of it.
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Post by echard on Nov 14, 2009 23:00:31 GMT -4
In a 1958 Time Magazine article, Van Allen himself said he didn't think the belts would be much of an issue for lunar-bound astronauts: www.time.com/time/magazine/article/0,9171,863443-2,00.html To cherry-pick a few sentences from the article: "The radiation zone is by no means a "death belt" that will keep humans from reaching space, but it might do some damage to men who live for a long time in a satellite" and "The crew of an outbound spaceship need not worry about the radiation belt." I guess Time was in on the hoax then too right? BTW, thanks from at least this, and I'm sure many more, lurkers who now understand orbital mechanics a bit better.
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Post by LunarOrbit on Nov 14, 2009 23:23:19 GMT -4
Except your questions have been solved, you just don't seem to realize it.
And for the record, I make no money from this forum. Since I have to pay for the web hosting and domain registration the hoax theory is actually costing me money. The only advertising revenue (from the Google Ads) goes to Proboards not to me.
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Post by fiveonit on Nov 15, 2009 0:52:19 GMT -4
Except your questions have been solved, you just don't seem to realize it. Furthermore, I would like to add that they were solved over 40 years ago!!! FM, your argument seems to be this.. "You are explaining things in a way that I don't understand so therefore you are against me!"If you don't understand the concepts that are being explained in this forum, here's a suggestion; go to school and get an eduction on the subject. Admittedly, I don't completely understand all of what Jay and many others discuss on this board, but then again, I don't blame them for my ignorance either!
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Post by fm on Nov 15, 2009 6:17:38 GMT -4
In a 1958 Time Magazine article, Van Allen himself said he didn't think the belts would be much of an issue for lunar-bound astronauts: www.time.com/time/magazine/article/0,9171,863443-2,00.html To cherry-pick a few sentences from the article: "The radiation zone is by no means a "death belt" that will keep humans from reaching space, but it might do some damage to men who live for a long time in a satellite" and "The crew of an outbound spaceship need not worry about the radiation belt." I guess Time was in on the hoax then too right? BTW, thanks from at least this, and I'm sure many more, lurkers who now understand orbital mechanics a bit better. Hey thank you for the article. Something I was wondering about actually. I understood that the Geiger counters could not measure what kind of radiation it was reading, only that there was radiation. But I was wondering, how bad was it for it to stop registering. So lets go cherry picking through that article you sent! But before we do, here is your basic Geiger Counter: RADIOACTIVITY - THE READINGS AND THE HAZARDS The following numbers are c.p.s. (counts per second), as a measurement of 'health hazard' they represent relative risk, if you are of the opinion that there is no 'safe' level of radioactivity it would be best to avoid anything with a reading above 2 c.p.s.
1 to 2: natural background level (good reading - shows Geiger counter is working properly) 3 or 4: slightly above background level 5 to 10: even at these low levels an item (e.g. watch) should not be kept next to skin for prolonged periods 10 to 100: do not carry the item next to the skin at all 100 to 200: do not to carry item close to your body, just handle it very occasionally 200 to 500: best not to handle the item at all - 700: Geiger counter overloads and gives continuous alarm - extreme caution!Ok so... Both Explorer I and Explorer III, said Van Allen, ran into a belt of intense radiation at about 600 miles elevation. At 1,100 kilometers (684 miles) the tubes registered as high as 140 counts per second. Then a strange thing happened. As the satellites climbed even higher, the transmitters reported no rays at all. During orbit after orbit the counter of Explorer III was silent for 15 minutes.Van Allen says The belt may extend outward for two earth radii (8,000) miles before it disappears.
So at this point, he doesn't even know about the OUTER BELT. Ok, so: he subjected a spare tube to X-ray bombardment in the laboratory. After studying its behavior, he decided that the tubes carried by the satellites must have passed through radiation equivalent to 35,000 counts per second, but were so choked up that they could not report their experience.Wow.... 35.000 cps. And 700 is already extreme caution? How do you suppose they would label 35.000 cps on a Geiger Counter ;D Back to the article: Van Allen figured that the radiation level inside the satellite might reach about 0.06 roentgens per hour. At this rate a man would receive in five hours his maximum weekly permissible dose of 0.3 roentgens.and... here is the kicker Echard. To protect a man from .06 roentgens per hour... A small amount of lead shielding would reduce the dose to a supportable level.
He didnt say add aluminum shielding. He states LEAD. And he goes on further to say: The crew of an outbound spaceship need not worry about the radiation belt. If moving fast enough to leave the earth, they would pass through it in about 20 minutes.So lets tally that one up. 1. One belt 2. Lead shielding 3. Radiation types unknown ( lead is not effective against all types of radiation ) 4. 5 hours max dose 5. 20 minute trip in the belt Is the basis for why he made that statement you quoted. So now why do you suppose Van Allen states later in 1959: "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? Lead not good enough? Trip not fast enough? Roentgen's too high? Other dangerous radiation types discovered? All of the above?? If you remember from your elementary or high school science class, radiation comes in varying strengths. The three types are alpha, beta, and gamma radiation. The energy particles associated with each have different energy levels. The best illustration is what materials they can penetrate. Alpha particle are the weakest. They can be easily blocked by a piece of paper or skin. Beta particles are stronger and can penetrate the skin. This is where we see the effects of radiation. It can strike DNA causing spontaneous mutations. However aluminum and other substances of similar density can deflect these particles. The strongest radiation particles of all are gamma particles. This is the most common type of radiation in space. Only the most dense substances can stop them and even then they are absorbed upon contact.Dense like.... lead? Because they sure didnt say use Aluminum as shielding for the most common type of radiation found in space. Strange how they would then use Aluminum for Apollo Here is something about roentgens: However, the roentgen has limitations. By definition it is limited to x- and gamma-rays, and medium of air, and does not include other types of radiation. Further, the definition of the roentgen holds only for lower energy radiations (up to 3 MeV)And here is something about lead: it is effective at stopping alpha rays, gamma rays, and x-rays. However, lead is not effective against all types of radiation. High energy electrons (including beta radiation) incident on lead may create bremsstrahlung radiation, which is potentially more dangerous to tissue than the original radiation. Furthermore, lead is not a particularly effective absorber of neutron radiation.
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Post by fm on Nov 15, 2009 6:59:07 GMT -4
fm: "Blah blah blah "flares can't be predicted" blah blah" citation? Date of citation? As I recall, flares were at least somewhat predictable, with a range of a couple of days, back when Apollo was flying. "A few days" being plenty sufficient for a three day mission. It is of course wildly insufficient for an extended duration mission to Mars for instance, which is why a new set of radiation studies is being done on the interplanetary environment. Also, "unpredictable" is not the same as "unobservable" - flare maxima are preceded by visible surface activity on the Sun, from which approximate intensity and primary vectors can be derived. On such a warning, astronauts can be ordered into their radiation shelter. Of course, this is a misdirection on your part as flares have very little to do with VAB radiation, which is particulate in nature and derived primarily from the solar wind, a separate phenomenon. You want to challenge the 8 minute claim? Go ahead, or should I in the future cite you as and expert in this area? Yeah ummm... according to a randombloke "As I recall, flares were at least somewhat predictable, with a range of a couple of days, back when Apollo was flying. "A few days" being plenty sufficient for a three day mission." and furthermore on a forum a randombloke says that " flares have very little to do with VAB radiation" I dont know what he thinks he means by this... but, if your going to trust someone, trust some randombloke. So by all means refute what I posted.
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