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Post by EshaNas on Aug 5, 2019 3:51:08 GMT
We all know that the Jovian moons are basically rad-cooked hot-rocks. Io, Europa, and Ganymede are too rad-hot for cursory visits or long-term habitation due to Jupiter's immense magnetic field. (This is partly why I hate Europa report so much). Callisto is 'okay'. Of course, altered, post, neo, or divergent humans or lifeforms might not mind, but let's say we're throwing out HOPE missions by the 2040-2060s and aren't throwing up rad-armored supercruisers or genetically altered supermen.  But what about the Saturnine system? Uranian system? Neptunian system? I can't find any numbers for them. Titan might be a rad-cooked rock, or not. Or maybe Titania or Miranda. I can't find any numbers. |
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Post by AtomHeartDragon on Aug 5, 2019 9:59:03 GMT
Titan is in the outer part of Saturn's (much weaker) magnetosphere AND has thick atmosphere. I would be worried about cold, not the radiation.
Outer giants have tilted magnetospheres, alleviating the issue.
Once you're on Callisto, there is nothing preventing you from taking as much water ice as you need and making rad shield out of it. Ganymede has its own magnetosphere around equatorial regions, shielding much of its surface, so once you can make it to the surface colonization should be possible.
Also ample ice everywhere.
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Post by airc777 on Aug 5, 2019 18:23:02 GMT
What's your source, and your numbers for the Jovian system being too radioactive to settle? How are you defining too radioactive to shield against?
Is this a not possible thing or a not a good idea thing? In theory are aren't many actually not possible things as long as you aren't violating causality or thermodynamics. In practice almost the entirety of space travel could be lumped in with not a good idea for any number of reasons, but engineers like solving problems and entrepreneurs like not having an upper bounds on how much they can expand, so humanity tends to ignore that and do it anyway.
The Jovian system being to radioactive to colonize would require some significant revisions to CoaDE's lore, yes?
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Post by AtomHeartDragon on Aug 5, 2019 20:55:27 GMT
Well, Jupiter's Van Allen's belts are some serious stuff.
OTOH you can have as much ice as you want once you reach Callisto (and that's with 126 milligee surface gravity) and charged particles can be kept out with active magnetic shielding too.
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Post by EshaNas on Aug 6, 2019 1:18:39 GMT
What's your source, and your numbers for the Jovian system being too radioactive to settle? How are you defining too radioactive to shield against? Is this a not possible thing or a not a good idea thing? In theory are aren't many actually not possible things as long as you aren't violating causality or thermodynamics. In practice almost the entirety of space travel could be lumped in with not a good idea for any number of reasons, but engineers like solving problems and entrepreneurs like not having an upper bounds on how much they can expand, so humanity tends to ignore that and do it anyway. The Jovian system being to radioactive to colonize would require some significant revisions to CoaDE's lore, yes? The inner three moons and the ring system is baked by the magnetosphere. My first numbers came from Zubrin's book Entering Space, Chapter 8, pg 167: "A radiation dose of 75 rem or more, if delivered during a short time compared to the cell repair and replacement cycles of the human body, say, 30 days, will generally cause radiation sickness, while doses over 500 rem will result in death.Moon - distance from Jupiter - radius (KM) - radiation dose (Rem per day)Metis - 127,960 - 20 - 18,000Adrastea - 128,980 - 10 -18,000Amalthea - 181,300 - 105 - 18,000Thebe - 221,900 - 50 - 18,000Io - 421,600 - 1,815 - 3,600Europa - 670,900 - 1,569 - 540Ganymede - 1,070,000 - 2631 - 8Callisto - 1,883,000 - 2,400 - 0.01 Leda - 1,1094,000 - 8 - 0Himalia - 1,1480,000 - 90 - 0Lysithea - 11,720,000 - 20 - 0Elara - 11,737,000 - 40 - 0Anake - 21,200,000 - 15 - 0Caeme - 22,600,000 - 22 - 0Pasiphae - 23,500,000 -35 - 0Sinope - 23,7000,000 - 20 - 0It can be seen that on Europa and all moons farther in, such fatal doses would be administered to unshielded humans within a single day. On Ganymede, the dose rate is not too bad, provided that people generally stayed in shielded quarters and only came out on he surface for a few hours now and then to perform essential tasks. On Callisto and those moons farther out, Jupiter's radiation belt are not an issue, except during the time of magneto tail pass-through...."While of course we won't be doing anything unshielded, our shielding capability is nothing to much goad about? We basically either zoom past it, or are planning to just go fast, and deal with minute exposure or basically give our electronics years to a decade of life and throw them out there to do their job. While looking for more concrete sources, I found this post: From what I gather from the Wikipedia article on Saturn's magnetosphere, the radiation environment is much less severe than Jupiter, and even than Earth... Two zones are to be avoided however: 1) There is a main radiation belt between the outer large visible A-ring at 2.3 Rs (Saturn radii, or 138 000 km) out to Enceladus, at 3 Rs (180 000 km)... 2) Another "hazardous" zone is a plasma sheet limited to the equatorial plane (0 degree inclination orbits) from 6 Rs (360 000 km) out to 14 Rs (840 000 km). Though again it seems numbers from Cassini aren't that...published? For some reason? |
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Post by AtomHeartDragon on Aug 6, 2019 9:04:32 GMT
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Post by airc777 on Aug 7, 2019 1:40:57 GMT
This seems like major concerns but not unsolvable problems. If nothing else Io is definitely still viable for autonomous mining with it's rocky composition and non existent atmosphere and 0.183g gravity and plenty of geothermal power. It's probably still viable for subterranean colonization.
Europa is much the same story with the added benefit of plenty of water.
Taking the idea of autonomous mining to it's most extreme destination then anywhere with enough of a heat gradient for power and enough resources is colonizable for post biological civilizations. Computers are less fragile.
Alternatively if you just wanted to colonize and exploit the Jovian system and you didn't actually care about landing you could build your habitation infrastructure as a space station in whatever orbit is the most reasonable and then operate semi autonomous surface mining operations from there.
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Post by dragon on Aug 7, 2019 21:20:51 GMT
Computers are actually much more fragile than living beings. It's an easy mistake to make, because we are complex beings that did not evolve in a high-radiation environment, but electronics die pretty quickly if exposed to extreme radiation. Their rad resistance is better because they're less complex than humans, not because of materials they're made of. Indeed, lack of self repair works against them, big time. Consider the story with the "elephant's foot" photographs from Chernobyl. A robotic vehicle they sent in fried because of heavy radiation (old Soviet gear, remember, not nanoscale ICs of today). Then they sent in an old guy with a mirror. And then he found mold growing in there. Feeding on gamma radiation, no less. I would say, if anything, a post-computer civilization would be needed to set up mining on Io.
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Post by airc777 on Aug 8, 2019 1:12:06 GMT
Is that not fixable with just Faraday cages and ecc memory and raid redundancy? You can build a computer to be whatever specifications you need it to be, the human body plan has restrictive design constraints.
You could put whatever environmental suit on the human, but if that's what you're defining as more durable then you can put whatever shielding on the computer and it will be smaller.
Treating humans as semi expendable via giving them a dosage allowance and then only getting a few man hours per year out of them doesn't sound more durable to me then just building a robot with the tolerances to do it continuously.
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Post by AtomHeartDragon on Aug 8, 2019 9:30:03 GMT
Faraday cage only helps with low frequency EM and static. It doesn't do anything with energetic particles.
And while you can try to make your computers redundant, biological systems are effectively built out of redundancy on lower levels.
Even if someone's DNA and much of their cellular machinery is shot to pieces by particle radiation, they will still stay a walking and talking (and puking, but nothing is ideal) person for quite while before dying horribly.
You really need huge radiation doses to fuck up central nervous system enough to immediately incapacitate and kill someone.
What skews our perception here is that we generally consider computers to be disposable, but not people.
Another factor is that a computer generally needs much smaller volume to shield.
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Post by dragon on Aug 8, 2019 22:53:25 GMT
The really big deal is that biological systems are self-regenerating. If you modified a human with a means of rapid, accurate DNA repair, radiation tolerance would go through the roof. Anything beyond an immediate CNS shutdown is, in theory, fixable, it's just a matter of being able to fix it fast enough without cancer-inducing errors. A computer will just accumulate damage until it inevitably breaks, and no amount of redundancy would save it, only delay the inevitable.
I was actually thinking of something more along the lines of genetically engineered radiotrophic fungi. Basically, grow a biological mat powered by radiation, that would eat Io's soil and excrete refined minerals to be scooped up by a heavily shielded spacecraft. Just make sure it's vulnerable to something we can easily spray it with, just in case it gets out of hand.
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Post by bigbombr on Aug 9, 2019 7:01:06 GMT
The really big deal is that biological systems are self-regenerating. If you modified a human with a means of rapid, accurate DNA repair, radiation tolerance would go through the roof. Anything beyond an immediate CNS shutdown is, in theory, fixable, it's just a matter of being able to fix it fast enough without cancer-inducing errors. A computer will just accumulate damage until it inevitably breaks, and no amount of redundancy would save it, only delay the inevitable. I was actually thinking of something more along the lines of genetically engineered radiotrophic fungi. Basically, grow a biological mat powered by radiation, that would eat Io's soil and excrete refined minerals to be scooped up by a heavily shielded spacecraft. Just make sure it's vulnerable to something we can easily spray it with, just in case it gets out of hand. Heat would work. Just microwave the fungi to kill it. |
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Post by dragon on Aug 9, 2019 9:51:34 GMT
If it's to be adapted to live on Io, then it would have to be engineered to be resistant to such things. The radiation belts have far more than just X-rays. However, the basic idea is sound, considering that Io is pretty cold on average. If they were optimized to live on Io, then simply warming them up to RT would most likely overheat them.
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Post by airc777 on Aug 10, 2019 8:04:10 GMT
I propose a fleet of dozen-kiloton bucket wheel excavators. Powered via orbital laser beamed power into a target thermal mass attached to Stirling engines with hundred-ton flywheels instead of Seebeck generators and then mechanically or hydraulically driving almost everything instead of electrically. Then we have the control computer inside a meter or more of shielding operating the craft with linear actuators and push/pull rods through pencil sized tubes in the bottom of the shielding. We then have it receive commands from the orbital station via whatever would be the most hardened and least noisy method, the station could send radar topography data for navigation. We then have similarly hardened autonomous dump trucks transporting material from the excavators to subterranean refineries and factories and launch silos. We try to engineer the excavators to have an operational life of ten Earth years or more and when they reach that to return to the factories to be refurbished or if they fail before then you would send your refinery workers on a salvage mission with hardend recovery vehicles transporting them to and from and eva at the salvage site.
If there's enough radiation that it physically breaks a hundred-ton flywheel on a simple Stirling engine then I vote we conceed defeat and file this under not possible instead of not a good idea. We come back later with the energy to break the entire moon and mine it as a ring.
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Post by EshaNas on Aug 13, 2019 0:25:33 GMT
I propose a fleet of dozen-kiloton bucket wheel excavators. Powered via orbital laser beamed power into a target thermal mass attached to Stirling engines with hundred-ton flywheels instead of Seebeck generators and then mechanically or hydraulically driving almost everything instead of electrically. Then we have the control computer inside a meter or more of shielding operating the craft with linear actuators and push/pull rods through pencil sized tubes in the bottom of the shielding. We then have it receive commands from the orbital station via whatever would be the most hardened and least noisy method, the station could send radar topography data for navigation. We then have similarly hardened autonomous dump trucks transporting material from the excavators to subterranean refineries and factories and launch silos. We try to engineer the excavators to have an operational life of ten Earth years or more and when they reach that to return to the factories to be refurbished or if they fail before then you would send your refinery workers on a salvage mission with hardend recovery vehicles transporting them to and from and eva at the salvage site. If there's enough radiation that it physically breaks a hundred-ton flywheel on a simple Stirling engine then I vote we conceed defeat and file this under not possible instead of not a good idea. We come back later with the energy to break the entire moon and mine it as a ring. I mean, it's not like we'll be gunning to colonise the rad-moons anyway. Callisto is fine. Titan is apparently fine. MAUTO - of Uranus - are fine. Triton and Probeus and the like - fine. There's a lot of real estate going around for now out there. |
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