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Thread: Moon Landing Question

  1. #241
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    I think if you tabulated the dosage received as crafts past through the South Atlantic Anomaly and used it as the basis to calculate the VAB transit you could approximate the actual dosage pretty close.I think it might not reflect the high end but it should be fairly representative of the low end.

  2. #242
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    Quote Originally Posted by VQkr View Post
    Bold added. Please show the calculation underlying this claim.
    This position is based on the fact that the VAB filters out 99% of Cosmic and Solar radiation. If you take the levels found in LEO then outside of the VAB you should expect levels to be 100 times as high.

  3. #243
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    Quote Originally Posted by grant hutchison View Post
    It's a large dataset, not a graph. AE9/AP9/SPM is the most current - you'll find an evaluation of its use in mission planning for a cislunar trajectory here, though I can't find a version that isn't behind a paywall or institutional login.
    AE8/AP8 is freely available for query here - you just specify your model and particle energies, type in a couple of magnetocentric coordinates, and you get a little table. Tedious.
    If you sign up for SPENVIS, you can create a spacecraft trajectory using geographical coordinates and then pull data for trapped electron and proton fluxes along that trajectory. Steep learning curve.

    Grant Hutchison
    We can make this work since you have the credentials go ahead and secure the transit dosage for the path the Apollo missions took and provide that number. I will do the rest.

  4. #244
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    It is interesting to note. that The extensive radiation mapping we rely on today did not exist in the late sixties. Things that make you go Hmmm?

  5. #245
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    Quote Originally Posted by bknight View Post
    And this means what in reference to the radiation VARB? Do you think the radiation in the VARB is the same as radiation from a reactor? If this is the case I begin to see your issues.
    There are four basic types of radiation and all of them are found in a nuclear reactor. So yes i believe radiation in a nuclear reactor translates to space.

  6. #246
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    Quote Originally Posted by pzkpfw View Post
    That puts even more context on your earlier claim:



    In a later post you wrote:



    Do you still assert the "any" in "lacked any radiation shielding" in the second quote above?

    (Of course being in the VAB isn't the same as being on the Moon; the point is the fact of different types of radiation and the shielding requirements thereof.)
    The Apollo craft utilized no dedicated shielding. Any shielding was a function of the construction material and the heat shields. The space suits had no other radiation shielding besides the reflective linen use to make them.
    Last edited by TimFinch; 2017-Oct-18 at 07:42 AM.

  7. #247
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    Quote Originally Posted by TimFinch View Post
    This position is based on the fact that the VAB filters out 99% of Cosmic and Solar radiation. If you take the levels found in LEO then outside of the VAB you should expect levels to be 100 times as high.
    But since that "fact" is inaccurate, why would you expect the conclusion to be correct?

  8. #248
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    Quote Originally Posted by VQkr View Post
    But since that "fact" is inaccurate, why would you expect the conclusion to be correct?
    What leads you to believe the VAB does not block 99% of solar and cosmic radiation? If it does not then what is the correct number?

  9. #249
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    Quote Originally Posted by TimFinch View Post
    What leads you to believe the VAB does not block 99% of solar and cosmic radiation? If it does not then what is the correct number?

    No, TimFinch, that is not how things works here. You are the one bringing the CT claim, so it is up to YOU to defend it. Shifting the burden of proof is not acceptable. So, either support your 99% claim with evidence, or retract it. You will do so immediately, or will be infracted for repeatedly evading this question throughout this thread.
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  10. #250
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    Gentleman here is the info on the reduction of Cosmic radiation. https://en.wikipedia.org/wiki/Health...om_cosmic_rays Click image for larger version. 

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  11. #251
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    Quote Originally Posted by TimFinch View Post
    Gentleman here is the info on the reduction of Cosmic radiation. https://en.wikipedia.org/wiki/Health...om_cosmic_rays Click image for larger version. 

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    I don't see any reference in that article to the 99% figure you've been repeatedly asserting. Please point it out or provide a reference that does support your claim. If you cannot we can dismiss your claim, as well as the others on which it depends.

  12. #252
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    Quote Originally Posted by TimFinch View Post
    Gentleman here is the info on the reduction of Cosmic radiation. https://en.wikipedia.org/wiki/Health...om_cosmic_rays Click image for larger version. 

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    That doesn't support your claim at all. You claimed 99% of all charged particle radiation was stopped. That says that the flux of galactic cosmic rays adds to our atmosphere about a billionth of the amount of energy that the Sun does.

  13. #253
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    Quote Originally Posted by Geo Kaplan View Post
    I don't see any reference in that article to the 99% figure you've been repeatedly asserting. Please point it out or provide a reference that does support your claim. If you cannot we can dismiss your claim, as well as the others on which it depends.
    I'm sorry. I thought enclosing it in yellow would make it obvious but I will spell it out for you. It states the input of GCR's is .000000001 of solar radiation, that is to say 99.99999999%.

  14. #254
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    Just for the sake of argument, Galactic and Solar cosmic rays are generally thought of as heavy particle radiation and not photons and electrons. It is the Cosmic particles that the earths magnetic field shields against. If it was photons then light would not reach earth.

  15. #255
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    Providing a quickly found wikipedia quote detailing how much less radiation from cosmic rather than solar origin reaches the atmosphere does not even come close to providing evidence that “the VAB blocks 99% of solar and cosmic radiaton”. Infraction issued for evading questions.

    The thread will remain closed to prevent a pile-up of questions, and can be reopened on return.

    Thread reopened.
    Last edited by slang; 2017-Oct-21 at 02:34 PM. Reason: reopened
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  16. #256
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    The relevant feature here is in any case not what proportion of particles are deflected by the magnetosphere, but by how much the radiation dose differs, above and below the Van Allen belts. And while the low energy particles of the solar wind may flow happily around the magnetopause, they’re not really a problem in terms of dose, because they’re mainly shielded out by the Apollo capsule. Whereas the very high energy protons from cosmic rays are minimally deflected by the Earth’s magnetic field, and end up striking the atmosphere. And they’re difficult to shield out, so contributing disproportionately to the absorbed dose inside a space capsule. So it seems that the magnetosphere is good at deflecting particles that aren’t a problem, but not at deflecting particles that are a problem. Which suggests another explanation of why LEO doesn’t seem much safer than interplanetary space.
    I suspect LEO and Low Lunar Orbit have lower measured doses than interplanetary space largely because they’re shadowed - they only receive a particle flux from half the sky.

    Grant Hutchison

  17. #257
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    Quote Originally Posted by TimFinch View Post
    I would accept anything that made sense and nothing that doesn't. Why do you think extrapolating the chart out would preclude approximating accurate results?
    Extrapolation is pretty much never a good idea. And in this case you’d be uselessly extrapolating data that do not contain the information you need, while a dataset exists that does contain the information you need.

    Quote Originally Posted by TimFinch View Post
    I think if you tabulated the dosage received as crafts past through the South Atlantic Anomaly and used it as the basis to calculate the VAB transit you could approximate the actual dosage pretty close.
    No, you couldn’t. The particle population of the SAA reflects the inner belt but not the outer belt.

    Quote Originally Posted by TimFinch View Post
    We can make this work since you have the credentials go ahead and secure the transit dosage for the path the Apollo missions took and provide that number. I will do the rest.
    It’s not clear to me what would actually be left for you to do. This is all stuff that you should have done before you ever turned up here with an unsupported argument. I’ve providing you with information and references concerning the relevant orbital dynamics, appropriate datasets and necessary calculations. You now have a complete plan for what you need to do, and access to the necessary resources. So it’s over to you.

    Quote Originally Posted by TimFinch View Post
    It is interesting to note. that The extensive radiation mapping we rely on today did not exist in the late sixties. Things that make you go Hmmm?
    Things that make me go ho-hum. The AE/AP series of trapped radiation models is an old series. We’re currently in transition between versions 8 and 9. AP7 and AE6 were both current in 1969. The version numbers tell the story.

    Quote Originally Posted by TimFinch View Post
    The Apollo craft utilized no dedicated shielding. Any shielding was a function of the construction material and the heat shields. The space suits had no other radiation shielding besides the reflective linen use to make them.
    Linen, not so much. Neoprene, nylon, Kapton, glass fibre, Mylar, beta cloth. Stuff can be both structural and shielding - that’s the sort of design decisions that engineers are employed to make. Turns out the construction materials used for the Apollo capsule and spacesuit are relevant to two of your four types of radiation.

    Grant Hutchison

  18. #258
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    The Apollo craft utilized no dedicated shielding. Any shielding was a function of the construction material and the heat shields. The space suits had no other radiation shielding besides the reflective linen use to make them.
    Quote Originally Posted by grant hutchison View Post
    Extrapolation is pretty much never a good idea. And in this case you’d be uselessly extrapolating data that do not contain the information you need, while a dataset exists that does contain the information you need.

    No, you couldn’t. The particle population of the SAA reflects the inner belt but not the outer belt.

    It’s not clear to me what would actually be left for you to do. This is all stuff that you should have done before you ever turned up here with an unsupported argument. I’ve providing you with information and references concerning the relevant orbital dynamics, appropriate datasets and necessary calculations. You now have a complete plan for what you need to do, and access to the necessary resources. So it’s over to you.

    Things that make me go ho-hum. The AE/AP series of trapped radiation models is an old series. We’re currently in transition between versions 8 and 9. AP7 and AE6 were both current in 1969. The version numbers tell the story.

    Linen, not so much. Neoprene, nylon, Kapton, glass fibre, Mylar, beta cloth. Stuff can be both structural and shielding - that’s the sort of design decisions that engineers are employed to make. Turns out the construction materials used for the Apollo capsule and spacesuit are relevant to two of your four types of radiation.

    Grant Hutchison
    Those high energy particles have a low flux, making effects small except on long term mission not the 14 day missions of Apollo.

    Indeed the construction material quite effectively shielded the astronauts with a layering of those materials you noted.

    I doubt that Tim will be convinced of his errors, but we can be hopeful.

    Quote Originally Posted by TimFinch View Post
    There are four basic types of radiation and all of them are found in a nuclear reactor. So yes i believe radiation in a nuclear reactor translates to space.
    Unfortunately it does not translate directly into space nor does this job experience necessarily translate to knowledge of shielding requirements.

    BTW: Time I have asked you a question that you have ignored or can't. I will ask again:

    I asked you a question earlier, which you have not answered, but may have overlooked with all the crowd postings.
    Please cite where the trajectory for Apollo missions was similar to Orion.

  19. #259
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    Quote Originally Posted by bknight View Post
    Those high energy particles have a low flux, making effects small except on long term mission not the 14 day missions of Apollo.
    Given that protons with energies > 100MeV penetrate the Apollo CM shielding, that means most of the galactic cosmic ray flux got into the Apollo capsule. It's certainly a relatively low dose rate (that's what we're discussing here, really!) but galactic cosmic rays account for most of the continuous background radiation dose for astronauts in interplanetary or cislunar space (ie, excluding Solar Particle Events).

    Grant Hutchison

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    Quote Originally Posted by TimFinch View Post
    I am a former Nuclear Plant supervisor and a radiation worker and you?
    I'm a current radiation worker and physical science technician; trained by the USN and served on several subs and shore facilities.

    Quote Originally Posted by TimFinch View Post
    The Apollo craft utilized no dedicated shielding. Any shielding was a function of the construction material and the heat shields. The space suits had no other radiation shielding besides the reflective linen use to make them.
    As said above shielding doesn't need to be "dedicated" to function or work effectively as shielding. As example would be the pressure hull of a submarine. Its primary purpose is to withstand sea pressure, it is also an effective gamma shield. All radiation workers also understand time/distance/shielding when it comes to reducing radiation exposure. Radiation energy also matters. How does the radiation you encountered at your facility compare to that the astronauts were exposed to? It's not really enough to say that it's alpha, beta, gamma or neutron.

    So we have the command module pressure vessel and other layers of material for protection (shielding), the path the spacecraft took through the VAB (distance) and the speed at which they passed through as well as the short duration mission (time). Was it worth the risk to land men on the moon? NASA thought so. In my opinion the radiation risk was rather low on the list of things to worry about.

    Ranb
    Last edited by ranb; 2017-Oct-21 at 10:03 PM.

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    Quote Originally Posted by ranb View Post
    Radiation energy also matters. How does the radiation you encountered at your facility compare to that the astronauts were exposed to? It's not really enough to say that it's alpha, beta, gamma or neutron.
    And most of the radiation in space comes from fusion reactions (sun, supernovae), not fission. So the particle population is distinctly different - very rich in protons, for example.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Given that protons with energies > 100MeV penetrate the Apollo CM shielding, that means most of the galactic cosmic ray flux got into the Apollo capsule. It's certainly a relatively low dose rate (that's what we're discussing here, really!) but galactic cosmic rays account for most of the continuous background radiation dose for astronauts in interplanetary or cislunar space (ie, excluding Solar Particle Events).

    Grant Hutchison
    You said it more eloquently than I but that is the general idea.

  23. #263
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    Quote Originally Posted by bknight View Post
    Those high energy particles have a low flux, making effects small except on long term mission not the 14 day missions of Apollo.

    Indeed the construction material quite effectively shielded the astronauts with a layering of those materials you noted.

    I doubt that Tim will be convinced of his errors, but we can be hopeful.



    Unfortunately it does not translate directly into space nor does this job experience necessarily translate to knowledge of shielding requirements.

    BTW: Time I have asked you a question that you have ignored or can't. I will ask again:

    I asked you a question earlier, which you have not answered, but may have overlooked with all the crowd postings.
    Please cite where the trajectory for Apollo missions was similar to Orion.
    https://ston.jsc.nasa.gov/collection...015-218575.pdf
    https://airandspace.si.edu/multimedia-gallery/5317hjpg
    Click image for larger version. 

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  24. #264
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    What was the apogee of Orion EFT1's highest orbit, in km and earth radii? How does this compare with the dimensions of the Van Allen belts and the Apollo transfer trajectories?

  25. #265
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    I think we've reached the point where the question that matters most is "What would make you change your mind?"
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    Quote Originally Posted by Gillianren View Post
    I think we've reached the point where the question that matters most is "What would make you change your mind?"
    And I for one already know what the response will be.

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    Yes, that's a nice diagram of the Apollo TLI trajectory, which missed the most intense part of the Van Allen belts and spent as little time in them as possible. Here's the Apollo 11 TLI trajectory rendered in Spenvis:
    http://h.dropcanvas.com/dew9d/apolloTLItrajectory.jpg
    Here's a top down view:
    http://h.dropcanvas.com/dew9d/apollo...trajectory.jpg
    And here is the expected dose predicted by Spenvis for the first 24 hours of that trajectory assuming stormy geomagnetic conditions and peak fluxes as a sort of worst case scenario:
    http://h.dropcanvas.com/dew9d/apolloTLIradiation.jpg
    Hardly what I would call dangerous. Now for comparison here is the Orion EFT-1 trajectory in Spenvis. I had to approximate the first orbit as space-track.org doesn't seem to have data for the first orbit, but they do have data on the much higher and more important second orbit and I used that to generate this plot:
    http://h.dropcanvas.com/dew9d/orioneft1trajectory.jpg
    A top down view:
    http://h.dropcanvas.com/dew9d/orione...trajectory.jpg
    And here is the expected dose for the Orion EFT-1 mission including both the initial parking and higher second orbit:
    http://h.dropcanvas.com/dew9d/orioneft1dose.jpg
    Given an Apollo spacecraft shielding of about 7~8 g/cm^2 you would receive several times more radiation from the much shorter Orion EFT-1 mission than traveling all the way through the Van Allen belts on an Apollo trans-lunar injection and even spending many more hours beyond the Van Allen belt after that.

  28. #268
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    Quote Originally Posted by NGCHunter View Post
    Yes, that's a nice diagram of the Apollo TLI trajectory, which missed the most intense part of the Van Allen belts and spent as little time in them as possible. Here's the Apollo 11 TLI trajectory rendered in Spenvis:
    http://h.dropcanvas.com/dew9d/apolloTLItrajectory.jpg
    Here's a top down view:
    http://h.dropcanvas.com/dew9d/apollo...trajectory.jpg
    And here is the expected dose predicted by Spenvis for the first 24 hours of that trajectory assuming stormy geomagnetic conditions and peak fluxes as a sort of worst case scenario:
    http://h.dropcanvas.com/dew9d/apolloTLIradiation.jpg
    Hardly what I would call dangerous. Now for comparison here is the Orion EFT-1 trajectory in Spenvis. I had to approximate the first orbit as space-track.org doesn't seem to have data for the first orbit, but they do have data on the much higher and more important second orbit and I used that to generate this plot:
    http://h.dropcanvas.com/dew9d/orioneft1trajectory.jpg
    A top down view:
    http://h.dropcanvas.com/dew9d/orione...trajectory.jpg
    And here is the expected dose for the Orion EFT-1 mission including both the initial parking and higher second orbit:
    http://h.dropcanvas.com/dew9d/orioneft1dose.jpg
    Given an Apollo spacecraft shielding of about 7~8 g/cm^2 you would receive several times more radiation from the much shorter Orion EFT-1 mission than traveling all the way through the Van Allen belts on an Apollo trans-lunar injection and even spending many more hours beyond the Van Allen belt after that.
    You are confusing me. Do you think you could travel 10000 km into the van allen belt with hardly any exposure? You do realize that NASA sent the Space shuttle to 345 miles and had to turn back because of radiation alarms and has never ventured that far in space since? I am not sure what your point is as there was no actual radiation levels on your diagram.

  29. #269
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    Quote Originally Posted by NGCHunter View Post
    Yes, that's a nice diagram of the Apollo TLI trajectory, which missed the most intense part of the Van Allen belts and spent as little time in them as possible. Here's the Apollo 11 TLI trajectory rendered in Spenvis:
    http://h.dropcanvas.com/dew9d/apolloTLItrajectory.jpg
    Here's a top down view:
    http://h.dropcanvas.com/dew9d/apollo...trajectory.jpg
    And here is the expected dose predicted by Spenvis for the first 24 hours of that trajectory assuming stormy geomagnetic conditions and peak fluxes as a sort of worst case scenario:
    http://h.dropcanvas.com/dew9d/apolloTLIradiation.jpg
    Hardly what I would call dangerous. Now for comparison here is the Orion EFT-1 trajectory in Spenvis. I had to approximate the first orbit as space-track.org doesn't seem to have data for the first orbit, but they do have data on the much higher and more important second orbit and I used that to generate this plot:
    http://h.dropcanvas.com/dew9d/orioneft1trajectory.jpg
    A top down view:
    http://h.dropcanvas.com/dew9d/orione...trajectory.jpg
    And here is the expected dose for the Orion EFT-1 mission including both the initial parking and higher second orbit:
    http://h.dropcanvas.com/dew9d/orioneft1dose.jpg
    Given an Apollo spacecraft shielding of about 7~8 g/cm^2 you would receive several times more radiation from the much shorter Orion EFT-1 mission than traveling all the way through the Van Allen belts on an Apollo trans-lunar injection and even spending many more hours beyond the Van Allen belt after that.
    Are you implying that the Apollo with shielding at or about 7.5 grams/cm^2 had greater shielding than the Orion?

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