jsisidore

EVA, IVA, IEVA suit gamma rad resistance

48 posts in this topic

I'm doing a research for a story/novel depends how far I will go, and I'm thinking which suit would be more protective of gamma radiation. Year is not important, but I would like to see the actual suit, it could be one of those first shiny suits made by nasa or soviets, or the modern ones, whichever is more effective. So far I have found out that lead is not the best element but cheapest and elements like gold, tungsten, mercury are better against gamma radiation.

The suit should be practical too. I mean a lead suit which is two inches thick would be too heavy to even imagine.

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Typically, you don't shield against gamma rays and x-rays. Shielding produces secondary radiation, it's safer to just let it all go through.

An interplanetary spaceship might use water, and lots of equipment and cargo stashed in the walls, as radiation shielding, along with a magnetic field against particle radiation.

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Posted (edited)

Also, gamma rays are so highly penetrating (you need tens of centimetres of lead to reduce their intensity to effectively zero, and then (as @SargeRho mentions above) you get potential for secondary radiation) that regardless of whether you make your spacesuit of thin layers of lead, gold, tungsten or spit-n-duct tape, you you don't reduce their intensity by much at all.

For some context, the following table is compiled from [1]

Shielding required for a 50% attenuation of 1200 keV* gamma rays.
Material Thickness / cm
Lead 1.0
Iron 1.8
Water 10.8

*1200 keV (or 1.2 MeV) is not particularly high energy, some radioactive decays can produce gamma rays up to about 10 MeV, cosmic rays can be in the GeV or, in extreme cases, TeV range.

[1] D. R. McAlister, Gamma Ray Attenuation Properties of Common Shielding Materials, Report for Postgraduate Research Foundation, 2013. Retrieved from http://www.eichrom.com/PDF/gamma-ray-attenuation-white-paper-by-d.m.-rev-4.pdf

Edited by Steel
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So in theory there can be no technology that can make a space suit protect you from gamma and x rays...

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2 hours ago, jsisidore said:

So in theory there can be no technology that can make a space suit protect you from gamma and x rays...

Well, no. You could make a reasonably radiation-proof suit. But it'd be less of a suit and more of a giant mech :P

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Posted (edited)

The suit that currently probably offers the most protection is the Newtsuit or its successor the Exosuit.
13_03a.jpg
However both those suits are deep water hardsuits capable of going down to close to a kilometre below the surface. A similar suit could very well be developed for space operations resulting in the 'giant mech' @SargeRho already mentioned.

Edited by Tex_NL
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@jsisidore, a "suit" capable of reliably shielding against lethal amounts of gamma rays would look something like this, which they used to handle the ejected reactor fuel in Chernobyl:

9418d02s-960.jpg

We're talking significant amounts of high-density armour plating all around. It's easier to do with a reactor because it's immobile and you can mix distance and directional shielding to further mitigate the thickness required.

I know the Chernobyl liquidators also used lead breastplates, but these were widely considered utterly ineffective.

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I see. What if humans would have a weekly cell cycle like cockroaches, I mean I have no idea if that is possible but what if we could, would we then need substantially less protection? Hmm evolved cockroaches, this reminds me of District 9... Would we willingly mutate to better adapt to our environment?

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3 hours ago, jsisidore said:

I see. What if humans would have a weekly cell cycle like cockroaches, I mean I have no idea if that is possible but what if we could, would we then need substantially less protection? Hmm evolved cockroaches, this reminds me of District 9... Would we willingly mutate to better adapt to our environment?

You simply need better cancer protection. And you don't mutate that takes forever, you change your genes.
Gama radiation is not the real danger its particles. best options is to use an remote-operated robot, it would also let you do stuff like repairing an nuclear engine. taking radiation like the armored vehicle above. 

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Which prompts an interesting alternate universe....

What if humans and other animals had no (none, zilch, 0%) susceptibility to radiation?

Where would we be now?

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3 hours ago, sevenperforce said:

Which prompts an interesting alternate universe....

What if humans and other animals had no (none, zilch, 0%) susceptibility to radiation?

Where would we be now?

Possibly still somewhere in the muds of tidal zones, gasping for breath.

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Posted (edited)

6 hours ago, sevenperforce said:

Which prompts an interesting alternate universe....

What if humans and other animals had no (none, zilch, 0%) susceptibility to radiation?

Where would we be now?

A fair question. Some suggest nowhere because radiation encourages mutation, bootstrapping evolution.

10 hours ago, jsisidore said:

I see. What if humans would have a weekly cell cycle like cockroaches, I mean I have no idea if that is possible but what if we could, would we then need substantially less protection? Hmm evolved cockroaches, this reminds me of District 9... Would we willingly mutate to better adapt to our environment?

Protection against radiation is two-fold. In the long term, radiation causes cancer; high cell replacement tempo would only make the tumors grow faster, we need more enhanced DNA repair mechanisms instead. Refer to Deinococcus radiodurans ("Conan the Bacterium") and Thermococcus gammatolerans. Short-term acute exposure (Acute Radiation Syndrome) is much simpler and boils down to, indeed, quick replacement of dead cells, especially white blood cells, and handling the various free radicals produced by radiolysis; there's a reason it's billed under "toxicology". We're already seeing the first radiation protection meds, such as Ex-Rad (keep your Fallout jokes about you).

Ultimately, pantropia, and radical adaptation of humans to whatever environment they are going to face, is just one solution to the problem of truly Earth-like planets not existing.

Edited by DDE
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7 hours ago, Shpaget said:

Possibly still somewhere in the muds of tidal zones, gasping for breath.

@DDE

I was thinking more of the immediate health impact, as discovered in the early 20th century. If Curie had not died of cancer, if no one ever got radiation poisoning, etc. 

Nuclear weapons would still be powerful, but there would be no deadly fallout. Nuclear energy would be completely benign. There would be no need for shielding.

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Posted (edited)

Physics is physics. If e.g. fast neutrons wouldn't damage atoms and molecules then matter/energy as we know it wouldn't exist. Also transmission of energy by radiation is real. We can't switch it off for x-rays and keep it intact for complex biological organisms.

Edit: so one could as well say, nuclear weapons / energy wouldn't exist, even an open fire might be problem because of lack of energy transport through radiation.

Sorry :-)

Edited by Green Baron

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13 minutes ago, Green Baron said:

Physics is physics. If e.g. fast neutrons wouldn't damage atoms and molecules then matter/energy as we know it wouldn't exist. Also transmission of energy by radiation is real. We can't switch it off for x-rays and keep it intact for complex biological organisms.

Edit: so one could as well say, nuclear weapons / energy wouldn't exist, even an open fire might be problem because of lack of energy transport through radiation.

Obviously.

Just a what-if, though. One could suppose that humans evolved faster cell repair mechanisms, or any other defense mechanism.

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1 hour ago, sevenperforce said:

@DDE

I was thinking more of the immediate health impact, as discovered in the early 20th century. If Curie had not died of cancer, if no one ever got radiation poisoning, etc. 

Nuclear weapons would still be powerful, but there would be no deadly fallout. Nuclear energy would be completely benign. There would be no need for shielding.

We would probably nuke ourselves into extinction long time ago. Destroying cities? Killing tens of thousands people in one go? Pffft. We've done it multiple times without nuclear weaponry - and it didn't deter us in the slightest. "We can always rebuild". On the other hand - the prospect of turning the Earth into inhospitable, irradiated Deathworld? Now that's a deterrent. Wars are waged to gain something. Turning everything into useless, deadly threat for generations to come... there is no gain in that. Not that we didn't try anyway... https://en.wikipedia.org/wiki/Neutron_bomb

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1 hour ago, sevenperforce said:

Obviously.

Just a what-if, though. One could suppose that humans evolved faster cell repair mechanisms, or any other defense mechanism.

You can't isolate a single feature out of a complex organism and say "now the organism is adapted to a new condition". Some archaea developed these repair mechanisms because they helped survive near hot geysers were life is harsh and chemistry runs fast.

A more complex organism like a vertebrate always has to trade between a lot of features that make it function and "fit" for given conditions as a whole. Changing a single feature (adding a "repair mechanism") might as well lead to a being that is "unfit" in other areas, like can't grow to a larger age, looses vital body functions, can't have a brain, looses ability to procreate, whatever.

I exaggerate: you can't take a tardigrade's temperature resistance, a human's brain and a bacteria's radiation tolerance and make a chimaera out if it. If such a thing was possible it would probably exist, or at least nature's tries in that direction would be somehow visible in the geological records. All these organisms work in their respective configuration for a given organism and a limited time only.

So, one could rather suppose that humans would not exist.

OT:

This is, btw., a thing palaeontologists are more aware of than geneticists. A single event does not lead to a resistant fully functional organism. Maybe one far day one can make a radiation resistant individual that even survives some time, but intermixture with the natural gene pool (i.e. humans) will sort the "faulty trait" out at once. That's why artificially bread organisms must not mix with the natural populations. The only solution would be to get rid of the "natural" ones, but that touches politics.

 

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2 hours ago, Green Baron said:

You can't isolate a single feature out of a complex organism and say "now the organism is adapted to a new condition". Some archaea developed these repair mechanisms because they helped survive near hot geysers were life is harsh and chemistry runs fast.

A more complex organism like a vertebrate always has to trade between a lot of features that make it function and "fit" for given conditions as a whole. Changing a single feature (adding a "repair mechanism") might as well lead to a being that is "unfit" in other areas, like can't grow to a larger age, looses vital body functions, can't have a brain, looses ability to procreate, whatever.

I exaggerate: you can't take a tardigrade's temperature resistance, a human's brain and a bacteria's radiation tolerance and make a chimaera out if it. If such a thing was possible it would probably exist, or at least nature's tries in that direction would be somehow visible in the geological records. All these organisms work in their respective configuration for a given organism and a limited time only.

So, one could rather suppose that humans would not exist.

OT:

This is, btw., a thing palaeontologists are more aware of than geneticists. A single event does not lead to a resistant fully functional organism. Maybe one far day one can make a radiation resistant individual that even survives some time, but intermixture with the natural gene pool (i.e. humans) will sort the "faulty trait" out at once. That's why artificially bread organisms must not mix with the natural populations. The only solution would be to get rid of the "natural" ones, but that touches politics.

 

More an issue, radiation resistance is not an survival trait, the chance of an animal dying of radiation is very small compared to other cases. 
Chernobyl became an wildlife preserve very fast. 
Few humans wanted to go there and government know hunters would sell meat so they banned hunting. 

Humans has safety requirements some order of magnitude higher than nature who don't care about individual survival. 
Much the same with cancer, an much larger issue but still nothing who create an selection pressure. One theory is that humans live so long is that grandparents are useful in an stone age tribe, they take care of kids and teach them skills while parents is out getting food and resources. 
If you want to live forever you have to earn it, luckily it lots of investment in the area, its the pill everybody want. 

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There are no (widespread) radiation-resistant organisms on Earth, because pretty much there never was an evolutionary pressure to develop such thing. We have organisms adapted to extreme temperatures, changes in water availability, acidity, salinity, lack of sunlight and whatnot. Because such conditions exist in biosphere, being niches living organisms can colonise. Until we started splitting the atom, there was no "irradiated niche" to encounter (well, except Oklo natural reactor - but it was extremely rare and localised event). But now we created such areas, and life is finding its way there - like the famous black mold growing on the walls of Chernobyl hotspot.

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15 minutes ago, magnemoe said:

More an issue, radiation resistance is not an survival trait, the chance of an animal dying of radiation is very small compared to other cases. 
 

I partly agree and i will not get into a political discussion :-)

Radiation sterilises and kicks the human males out of the reproduction game. If you had several unshielded x-rays at young age you have a good chance of not having a chance. So, yes, it could be a fitness criteria if selection pressure went in that direction (sorting out the more receptive ones).

Let's go on with this borderless guessing: very early such a pressure existed apparently, that is why some basic organisms actually developed such an ability, but it wasn't traded over to more complex organisms. I am referring to the rather young fashion of setting the first life forms on earth near submarine extreme environments (but nobody exclude other possibilities).

The reason might be that such an ability might not be in favour of building a complex organism because it has other, more grave disadvantages. And / or that it is, as you say, not a fitness criteria. I cannot exclude that and it even seems probable to me.

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This is a bit too sciency for me but I'll try.

In relation with radiation and evolution are we talking about free radicals? A bit of chaos to spice things up?

Wiki says ex-rad works with damaged dna as it is more effective than "scavenging" for free radicals. That is a very interesting plot device.

I am a believer that we're still evolving. We can only look back and when we compare ourselves with primates we get a feeling that this is it, we made it, buuut I'm not so sure. In anyway, we have evolved to be resistant to some forms of radiation, but with some help from bio-engineering I think we can accelerate and tweak this process if the need will arise...

Mechas are fun but I'm looking at global disasters and not so much local ones.

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3 hours ago, Scotius said:

There are no (widespread) radiation-resistant organisms on Earth, because pretty much there never was an evolutionary pressure to develop such thing. We have organisms adapted to extreme temperatures, changes in water availability, acidity, salinity, lack of sunlight and whatnot. Because such conditions exist in biosphere, being niches living organisms can colonise. Until we started splitting the atom, there was no "irradiated niche" to encounter (well, except Oklo natural reactor - but it was extremely rare and localised event). But now we created such areas, and life is finding its way there - like the famous black mold growing on the walls of Chernobyl hotspot.

Fascinating. That black mold could be our legacy if we won't make it for some reason.

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Posted (edited)

@jsisidore For the purposes of a story, a drug similar ex-rad and a healthy dose of genetic engineering would be enough to achieve whatever radiation related plot point it is that you want. Whether or not it is entirely scientifically accurate is another question, but it would be accurate enough that very few people could say for certain whether or not you are wrong.

What you say about evolution is true as well. Evolution never stops, but because it is a process that manifests over thousands of generations it's impossible to perceive it happening (and oddly enough, there are many who believe that one of the contributing factors to the genetic mutations that cause evolution over time is DNA damaged by radiation)

Edited by Steel
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Posted (edited)

12 minutes ago, Steel said:

@jsisidore For the purposes of a story, a drug similar ex-rad and a healthy dose of genetic engineering would be enough to achieve whatever radiation related plot point it is that you want. Whether or not it is entirely scientifically accurate is another question, but it would be accurate enough that very few people could say for certain whether or not you are wrong.

What you say about evolution is true as well. Evolution never stops, but because it is a process that manifests over thousands of generations it's impossible to perceive it happening (and oddly enough, there are many who believe that one of the contributing factors to the genetic mutations that cause evolution over time is DNA damaged by radiation)

Seems like dna is naturally lazy and needs a kick in form of radiation. You could say it is life on the most basic level and we are here only to spread dna.

Edited by jsisidore

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The thing is, radiation damages and alter the DNA structure that might cause a mutation. However, in order to "evolve"  or "adapt" it means the same alteration of the entire DNA in your body on the level of every cell. Humans cannot evolve by simply living near nuclear / radiation source long enough. The alteration to the DNA would be too random across all cells in the body that the probability to gain a resistance against it is very low (unless you use a genetically modified human as a plot device. But that's another story)

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