5 ms·

Artemis II and the invisible hazard on the way to the Moon

87 points by zeristor 6mo ago

Terr_ 6mo ago
> Dose rate matters. Particle type matters. Direction matters. Shielding matters. There's an old story where a professor quizzes his physics class about how to most-safely distribute different kinds of radiation sources. A common variation involves three baked cookies, emitting alpha particles, beta, and gamma respectively. One must be eaten, one must be held in your hand, and one must be placed in a pocket. A hint, and what I think is the interesting part of the answer, involves the idea that a victim is a lot like shielding. Things which are difficult to block are also things that are less-likely to stop and ruin your day.
- voidUpdate 6mo ago
  Are we protecting the person with the cookies, or everyone else? I'm struggling to think of the best answer Alpha: In the hand held away from the body would be reasonably safe. In a pocket of a lab coat might provide a little more shielding from the body with the coat material, but it is physically closer. Eaten would be very bad for the user, but protect the outside world the best Beta: Medium penetration, would likely not be safe in any of these three situations Gamma: High penetration, definitely not safe in any of these situations, best would be to get it as far away from you as possible, so held at arms length would mean you might only get high radiation exposure in your hand. Hospital visit is probably needed in any of these three situations
  - Terr_ 6mo ago
    IIRC: * Alpha in hand. Eaten, the "shielding" that blocks it will actually be very active living cells, leading to severe health outcomes. Your external layers of dead skin cells will be be fine, putting it in your pocket would be excessive. * Gamma in hand, because whether it's in your hand or in your pocket, it's roughly the same risk, and most of it is actually going through you without stopping to have an effect. (Compared to other two.) * Beta in pocket, where the additional clothing layer(s) offer some meaningful protection compared to your hand. The "twist" behind the exercise involves how people often assume penetrative power is proportional to danger, when in some ways it's really the opposite. (Consider the danger profile of neutrinos.)
    - voidUpdate 6mo ago
      Oh, I thought you have to choose one of the options for each cookie, no repeats
      - bennettnate5 6mo ago
        I guess in that case it would be to eat gamma? Assuming you're keeping all three long-term, the gamma particles will be washing over you whether they're inside you or out.
      - Terr_ 6mo ago
        You're quite correct, the light of the morning and flu-medicine what I should've written is: * Gamma is [eaten], because whether [wherever it is], it's roughly the same risk, and most of it is actually going through you without stopping to have an effect. (Compared to other two.) Naturally there's a whole bunch of unstated "all else being equal" going on, where no cookie's' elements are extra-likely to be permanently incorporated into your bones versus excreted, etc.
    - K0balt 6mo ago
      Same with x-rays. People tend to think “soft” X-rays are safer because they are quickly absorbed by tissue without passing through. The radiation that passes through is not the problem.
  - SiempreViernes 6mo ago
    Sure, using the ambiguous wording to assume the cookies all have such a large activity they are unsafe no matter how they are stored is technically a solution. But it's equally possible the teacher is imagining the cookies as only slightly radioactive such that it is indeed possibly to safely store them according to the alternatives given if you choose the correct pairs.
  - Eddy_Viscosity2 6mo ago
    Can these cookies be weaponized? Are there secret cookie enrichment factories? Would weapons-grade cookies still be good with milk?
    - mwigdahl 6mo ago
      Only weapons-grade milk.
      - BuyMyBitcoins 6mo ago
        Heavy milk (whole) is required for cookie enrichment. But depleted milk (skim) still has value.
        dgacmu 6mo ago
        Commonly used as a projectile
  - tyho 6mo ago
    Eat the gamma cookie, it's the worst option for any, but with gamma it won't matter much whether it's in your hand, pocket or gut. Pocket the beta emitter, a little bit of shielding will make a big difference. Hold the alpha emitter, if you hold it with just a pair of fingers you will be able to reduce you dosage a lot compared to holding it tightly.
    - PunchyHamster 6mo ago
      wouldn't alpha be mostly stopped just in pocket ? I'd hold beta emitter, less area of body affected by the radiation if you hold it at distance
- mazokum 6mo ago
  I heard about this question in the MIT Ionising Radiation course. You can find it here, around minute 47:30 (wont spoil the answer). https://ocw.mit.edu/courses/22-01-introduction-to-nuclear-engineering-and-ionizing-radiation-fall-2016/resources/radioactive-decay2014modes-energetics-and-trends/ https://ocw.mit.edu/courses/22-01-introduction-to-nuclear-en...
  - j33pers 6mo ago
    Thanks, I watched it. There are 4 cookies - a gamma, alpha, beta and neutrino emitter. You must eat one, pocket one, hold one and give one away.
- throwanem 6mo ago
  Eat the gamma, pocket the beta, hold the alpha. Nothing in the picture here stops gamma rays so it doesn't matter what you do with those; skin will stop alpha particles, but so will mucosa (and you die of that); in your pocket, the beta source will spall X-rays off your trousers at least some of the time so the beta burns will be mitigated.
- 1970-01-01 6mo ago
  Take with iodine.
zeristor 6mo ago
I thought one of the things with New Space is that Commercial off the Shelf parts were being used more and more. I’m assuming if that’s a case there have been more mishaps. How does SpaceX tackle this with both the rockets, and the thousand of Starlinks.
- ksaj 6mo ago
  Something they say in music: Repetition Legitimizes.
- spacedoutman 6mo ago
  The threat of radiation is severely overblown. NASA is overpaying for underperforming "hardened" hardware that performs no better than non-hardened. You can see this yourself with the mars helicopter ingenuity. If you are desperate for extra safety then just include multiple computers, literally what spacex does.
  - adrian_b 6mo ago
    The threat of radiation is not overblown at all. The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space. However that does not necessarily require hardware measures. It may be more efficient if instead of a slow antique CPU with hardware redundancy you use a fast modern CPU, even if it is more sensitive to radiation and even when it lacks hardware redundancy, but you do each computation several times, verifying that every time you get the same result, and if possible you use different algorithms or verification methods, to be able to detect some permanent errors. This is what the Mars helicopter did. If it had used standard smartphone software, the helicopter would have failed instantly.
    - gambiting 6mo ago
      >>The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space. I asked this in another thread but I will repeat it here - how come that their bog standard iPhones that they use for taking pictures with are still operating fine then? If like you said, "anything will fail immediately" - doesn't sound like that's the case? They have electronic watches with no radiation hardening, they have regular laptops with no radiation hardening.....I'm not saying that it's not a problem, but it definitely doesn't seem to be in the area of "immediately failing in space" if you don't have that.
voidUpdate 6mo ago
I enjoy how moon-landing deniers will use the van Allen belts as a reason for why the astronauts could not have made it to the moon because of radiation exposure. Like, you don't believe NASA that they went to the moon, but you believe NASA that the van Allen belts exist?
- joeslide 6mo ago
  [flagged]
- arowthway 6mo ago
  I'm not disputing that conspiracy theorists tend to lack rigor but there is a full spectrum of positions between "space is fake" and "one specific extraordinary achievement with high incentive to fake it is fake".
  - glimshe 6mo ago
    There's indeed a full spectrum of positions in this case, but they are all worthless in the sense that they add nothing to someone's understanding of reality.
    - zurfer 6mo ago
      You know some people grow up in untrustworthy environments and auto didact their way to something like first principles thinking and depending on things shaking out you might only believe what you've personally seen with your own eyes. And well, earth looks pretty flat in daily life.
- JumpCrisscross 6mo ago
  Any entertaining “Artemis II is a hoax” takes?
  - hydrogen7800 6mo ago
    I haven't been actively looking for them, but a friend sent me something about the launch tower escape zipline/gondolas and how that somehow indicated something fraudulent. He is not a denier, but works with one and is always asking me to refute that person's claims.
baggachipz 6mo ago
> Artemis II and the invisible hazard Decent Harry Potter book title

87 points by zeristor 6mo ago

Terr_ 6mo ago

> Dose rate matters. Particle type matters. Direction matters. Shielding matters. There's an old story where a professor quizzes his physics class about how to most-safely distribute different kinds of radiation sources. A common variation involves three baked cookies, emitting alpha particles, beta, and gamma respectively. One must be eaten, one must be held in your hand, and one must be placed in a pocket. A hint, and what I think is the interesting part of the answer, involves the idea that a victim is a lot like shielding. Things which are difficult to block are also things that are less-likely to stop and ruin your day.

voidUpdate 6mo ago
Are we protecting the person with the cookies, or everyone else? I'm struggling to think of the best answer Alpha: In the hand held away from the body would be reasonably safe. In a pocket of a lab coat might provide a little more shielding from the body with the coat material, but it is physically closer. Eaten would be very bad for the user, but protect the outside world the best Beta: Medium penetration, would likely not be safe in any of these three situations Gamma: High penetration, definitely not safe in any of these situations, best would be to get it as far away from you as possible, so held at arms length would mean you might only get high radiation exposure in your hand. Hospital visit is probably needed in any of these three situations
- Terr_ 6mo ago
  IIRC: * Alpha in hand. Eaten, the "shielding" that blocks it will actually be very active living cells, leading to severe health outcomes. Your external layers of dead skin cells will be be fine, putting it in your pocket would be excessive. * Gamma in hand, because whether it's in your hand or in your pocket, it's roughly the same risk, and most of it is actually going through you without stopping to have an effect. (Compared to other two.) * Beta in pocket, where the additional clothing layer(s) offer some meaningful protection compared to your hand. The "twist" behind the exercise involves how people often assume penetrative power is proportional to danger, when in some ways it's really the opposite. (Consider the danger profile of neutrinos.)
  - voidUpdate 6mo ago
    Oh, I thought you have to choose one of the options for each cookie, no repeats
    - bennettnate5 6mo ago
      I guess in that case it would be to eat gamma? Assuming you're keeping all three long-term, the gamma particles will be washing over you whether they're inside you or out.
    - Terr_ 6mo ago
      You're quite correct, the light of the morning and flu-medicine what I should've written is: * Gamma is [eaten], because whether [wherever it is], it's roughly the same risk, and most of it is actually going through you without stopping to have an effect. (Compared to other two.) Naturally there's a whole bunch of unstated "all else being equal" going on, where no cookie's' elements are extra-likely to be permanently incorporated into your bones versus excreted, etc.
  - K0balt 6mo ago
    Same with x-rays. People tend to think “soft” X-rays are safer because they are quickly absorbed by tissue without passing through. The radiation that passes through is not the problem.
- SiempreViernes 6mo ago
  Sure, using the ambiguous wording to assume the cookies all have such a large activity they are unsafe no matter how they are stored is technically a solution. But it's equally possible the teacher is imagining the cookies as only slightly radioactive such that it is indeed possibly to safely store them according to the alternatives given if you choose the correct pairs.
- Eddy_Viscosity2 6mo ago
  Can these cookies be weaponized? Are there secret cookie enrichment factories? Would weapons-grade cookies still be good with milk?
  - mwigdahl 6mo ago
    Only weapons-grade milk.
    - BuyMyBitcoins 6mo ago
      Heavy milk (whole) is required for cookie enrichment. But depleted milk (skim) still has value.
      - dgacmu 6mo ago
        Commonly used as a projectile
- tyho 6mo ago
  Eat the gamma cookie, it's the worst option for any, but with gamma it won't matter much whether it's in your hand, pocket or gut. Pocket the beta emitter, a little bit of shielding will make a big difference. Hold the alpha emitter, if you hold it with just a pair of fingers you will be able to reduce you dosage a lot compared to holding it tightly.
  - PunchyHamster 6mo ago
    wouldn't alpha be mostly stopped just in pocket ? I'd hold beta emitter, less area of body affected by the radiation if you hold it at distance
mazokum 6mo ago
I heard about this question in the MIT Ionising Radiation course. You can find it here, around minute 47:30 (wont spoil the answer). https://ocw.mit.edu/courses/22-01-introduction-to-nuclear-engineering-and-ionizing-radiation-fall-2016/resources/radioactive-decay2014modes-energetics-and-trends/ https://ocw.mit.edu/courses/22-01-introduction-to-nuclear-en...
- j33pers 6mo ago
  Thanks, I watched it. There are 4 cookies - a gamma, alpha, beta and neutrino emitter. You must eat one, pocket one, hold one and give one away.
throwanem 6mo ago
Eat the gamma, pocket the beta, hold the alpha. Nothing in the picture here stops gamma rays so it doesn't matter what you do with those; skin will stop alpha particles, but so will mucosa (and you die of that); in your pocket, the beta source will spall X-rays off your trousers at least some of the time so the beta burns will be mitigated.
1970-01-01 6mo ago
Take with iodine.

zeristor 6mo ago

I thought one of the things with New Space is that Commercial off the Shelf parts were being used more and more. I’m assuming if that’s a case there have been more mishaps. How does SpaceX tackle this with both the rockets, and the thousand of Starlinks.

ksaj 6mo ago
Something they say in music: Repetition Legitimizes.
spacedoutman 6mo ago
The threat of radiation is severely overblown. NASA is overpaying for underperforming "hardened" hardware that performs no better than non-hardened. You can see this yourself with the mars helicopter ingenuity. If you are desperate for extra safety then just include multiple computers, literally what spacex does.
- adrian_b 6mo ago
  The threat of radiation is not overblown at all. The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space. However that does not necessarily require hardware measures. It may be more efficient if instead of a slow antique CPU with hardware redundancy you use a fast modern CPU, even if it is more sensitive to radiation and even when it lacks hardware redundancy, but you do each computation several times, verifying that every time you get the same result, and if possible you use different algorithms or verification methods, to be able to detect some permanent errors. This is what the Mars helicopter did. If it had used standard smartphone software, the helicopter would have failed instantly.
  - gambiting 6mo ago
    >>The errors caused by radiation are extremely frequent and you definitely must guard against them, otherwise anything will fail immediately in space. I asked this in another thread but I will repeat it here - how come that their bog standard iPhones that they use for taking pictures with are still operating fine then? If like you said, "anything will fail immediately" - doesn't sound like that's the case? They have electronic watches with no radiation hardening, they have regular laptops with no radiation hardening.....I'm not saying that it's not a problem, but it definitely doesn't seem to be in the area of "immediately failing in space" if you don't have that.

voidUpdate 6mo ago

I enjoy how moon-landing deniers will use the van Allen belts as a reason for why the astronauts could not have made it to the moon because of radiation exposure. Like, you don't believe NASA that they went to the moon, but you believe NASA that the van Allen belts exist?

joeslide 6mo ago
[flagged]
arowthway 6mo ago
I'm not disputing that conspiracy theorists tend to lack rigor but there is a full spectrum of positions between "space is fake" and "one specific extraordinary achievement with high incentive to fake it is fake".
- glimshe 6mo ago
  There's indeed a full spectrum of positions in this case, but they are all worthless in the sense that they add nothing to someone's understanding of reality.
  - zurfer 6mo ago
    You know some people grow up in untrustworthy environments and auto didact their way to something like first principles thinking and depending on things shaking out you might only believe what you've personally seen with your own eyes. And well, earth looks pretty flat in daily life.
JumpCrisscross 6mo ago
Any entertaining “Artemis II is a hoax” takes?
- hydrogen7800 6mo ago
  I haven't been actively looking for them, but a friend sent me something about the launch tower escape zipline/gondolas and how that somehow indicated something fraudulent. He is not a denier, but works with one and is always asking me to refute that person's claims.

baggachipz 6mo ago

> Artemis II and the invisible hazard Decent Harry Potter book title