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Post by newageofpower on Apr 28, 2017 7:17:20 GMT
SevenOfCarinaHmm. Why would anyone build laserstars during a time of relative peace?
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Post by SevenOfCarina on Apr 28, 2017 8:21:42 GMT
I wasn't being literal. They could just be building solar power stations and laserboost systems for all we know. Or they could be attempting to go laserstar diplomacy on everyone. In the midst of a crisis, I doubt people would notice certain unscrupulous individuals with enough funds building themselves a hundred meter radius collector at say, 0.1 AU. Or even Mercury orbit, at 0.39 AU. Solar irradiance would fluctuate between 6.4 and 14 kW/m^2, so that's 200 GW - 440 GW. Is a hundred meter array fairly large? But, as such, there would be little use for laserboost systems. Very early in, merely getting material off the planet is going to be a huge headache, with no mass drivers or laser launch systems. Plus, demand would drop crazy fast once Earth's market goes offline. But, if there were sufficient warning, would there be a sharp rise in demand for orbital construction and materials as people sought to leave? It could be a trigger for a strong space economy.
Regarding the impactor, how plausible is it for a ~40 km rock hurtling in at >50 km/s to remain unnoticed till a few years before impact? It would definitely be an ELE, but I doubt at least some (~100 million - 1 billion) people wouldn't survive, at least, initially. Also, what would be our prospects of deflecting a multi-trillion ton rock? How feasable would such an impactor even be? It'll likely be more ice than rock, at its velocity, so would an iceball/comet complicate matters? Can nuclear weapons ablate enough ice fast enough to deflect it? Chemical drives are out, since there's no way they'll be able to match velocity - can nuclear/nuclear-electric drives make it there fast enough? Can a few puny ground-based GW laser-launch systems ablate the ice/rock fast enough? Can laserstations be built around Mercury fast enough, with almost no existing infrastructure? Lastly, how bad will such an impactor be, considering its fairly high impact velocity and energy (~160 YJ / 38.4 Petatons of TNT / 6.6 times the maximum postulated energy of the Chixculub impactor)?
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Post by The Astronomer on Apr 28, 2017 8:52:21 GMT
I wasn't being literal. They could just be building solar power stations and laserboost systems for all we know. Or they could be attempting to go laserstar diplomacy on everyone. In the midst of a crisis, I doubt people would notice certain unscrupulous individuals with enough funds building themselves a hundred meter radius collector at say, 0.1 AU. Or even Mercury orbit, at 0.39 AU. Solar irradiance would fluctuate between 6.4 and 14 kW/m^2, so that's 200 GW - 440 GW. Is a hundred meter array fairly large? But, as such, there would be little use for laserboost systems. Very early in, merely getting material off the planet is going to be a huge headache, with no mass drivers or laser launch systems. Plus, demand would drop crazy fast once Earth's market goes offline. But, if there were sufficient warning, would there be a sharp rise in demand for orbital construction and materials as people sought to leave? It could be a trigger for a strong space economy. Regarding the impactor, how plausible is it for a ~40 km rock hurtling in at >50 km/s to remain unnoticed till a few years before impact? It would definitely be an ELE, but I doubt at least some (~100 million - 1 billion) people wouldn't survive, at least, initially. Also, what would be our prospects of deflecting a multi-trillion ton rock? How feasable would such an impactor even be? It'll likely be more ice than rock, at its velocity, so would an iceball/comet complicate matters? Can nuclear weapons ablate enough ice fast enough to deflect it? Chemical drives are out, since there's no way they'll be able to match velocity - can nuclear/nuclear-electric drives make it there fast enough? Can a few puny ground-based GW laser-launch systems ablate the ice/rock fast enough? Can laserstations be built around Mercury fast enough, with almost no existing infrastructure? Lastly, how bad will such an impactor be, considering its fairly high impact velocity and energy (~160 YJ / 38.4 Petatons of TNT / 6.6 times the maximum postulated energy of the Chixculub impactor)? Diverted asteroids? Call in casaba howitzers!
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Post by SevenOfCarina on Apr 28, 2017 8:58:53 GMT
Diverting asteroids with nuclear shotguns? With no pre-existing prototypes? How effective would Casaba-Howitzers be in compaison to laser ablation? Could the tech be devoped fast enough from a near-standing start?
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Post by The Astronomer on Apr 28, 2017 9:04:30 GMT
Diverting asteroids with nuclear shotguns? With no pre-existing prototypes? How effective would Casaba-Howitzers be in compaison to laser ablation? Could the tech be devoped fast enough from a near-standing start? Wait a minute. I am wondering why the technology in your world progress so slowly.
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Post by newageofpower on Apr 28, 2017 9:11:47 GMT
The AstronomerCasaba Howitzers and other standoff nuclear weapons would be far less effective than a simple shaped nuclear charges at asteroid deflection. Casabas and bomb-pumped lasers utilize a few % of a warhead's total energy, while a shaped nuclear device could give you double digit efficiencies in energy transfer. Unless you have a very large stockpile of nukes, though, I think the high efficiency giant lasers are superior for asteroid deflection purposes. SevenOfCarinaAs for how bad the impact would be, it depends. Where is it hitting?
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Post by SevenOfCarina on Apr 28, 2017 9:25:04 GMT
Wait a minute. Backtrack a bit, and you'll notice that I changed the setting timeline to prevent post-scarcity killing any potential for conflict. Plus, if I scrap fusion and go with nuclear thermal tech, I can simply used CoaDE for modelling vessels. An earlier setting will also allow for more accurate predictions of technology - enough advances will take place on ~50 year timescales anyway. Fusion would be out, I can see something crazy like an NSWR being attempted out of desperation, but the average person would likely be limited to good old NTRs and chemical rockets. Earth can retain control over any Martian colony owing to an early settlement's dependance on imported metals and organics, especially fertilizer. Venus should be slightly better-off, at least in regards to nitrogen, and water can be extracted from the atmospheric H2SO4 by simply descending.
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Post by SevenOfCarina on Apr 28, 2017 9:35:10 GMT
Water would cushion the impact, so I'm thinking of a hit on solid ground at the mid-latitudes in the Eastern hemisphere. Somewhere around 30-40 degrees North and 80-100 degrees East, smack bang in the middle of the Tibetan plateau.
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Post by The Astronomer on Apr 28, 2017 9:37:43 GMT
The Astronomer Casaba Howitzers and other standoff nuclear weapons would be far less effective than a simple shaped nuclear charges at asteroid deflection. Casabas and bomb-pumped lasers utilize a few % of a warhead's total energy, while a shaped nuclear device could give you double digit efficiencies in energy transfer... What are the difference between Casaba Howitzer and Shaped Nuclear Charges? I thought they were the same? Water would cushion the impact, so I'm thinking of a hit on solid ground at the mid-latitudes in the Eastern hemisphere. Somewhere around 30-40 degrees North and 80-100 degrees East, smack bang in the middle of the Tibatan plateau. Make sure to read any asteroid impact articles you came across. The effects are very complex, but from one report, wind and shockwave is the most devastating for a normal asteroid, together accounting 60% of the total death toll (though the wind is far more destructive).
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Post by newageofpower on Apr 28, 2017 9:59:11 GMT
Casabas are tuned for long range engagements; fractions of a light second for higher-end devices. They sacrifice total energy efficiency for a more focused jet for effectiveness. Meanwhile, the stereotypical Orion Pulse unit is designed to detonate within a few hundred meters of the target. Much more of the energy reaches the target, but obviously you have little standoff. SevenOfCarinaHm. With such limited industrial tech, and assuming hab tech is likewise hamstrung, I would forsee most pre-collapse colonization occur around Mars or the Jovians. Venus is easy to live on, but extracting industrial resources from it is going to be hard, thus crippling any attempts at industrial expansion. Unless you have a giant megacorp based on Venus that coerces Belter clans to make shipments of industrial metals towards Venus, aerobraking into Low Venusian Orbit to save dV... Better yet, Venusian megacorp diverts entire asteroids - electric drive plus nuclear power. No aerobreaking for this kind of stuff though, the risk of catastrophe is simply too high.
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Post by bigbombr on Apr 28, 2017 10:09:00 GMT
I wasn't being literal. They could just be building solar power stations and laserboost systems for all we know. Or they could be attempting to go laserstar diplomacy on everyone. In the midst of a crisis, I doubt people would notice certain unscrupulous individuals with enough funds building themselves a hundred meter radius collector at say, 0.1 AU. Or even Mercury orbit, at 0.39 AU. Solar irradiance would fluctuate between 6.4 and 14 kW/m^2, so that's 200 GW - 440 GW. Is a hundred meter array fairly large? But, as such, there would be little use for laserboost systems. Very early in, merely getting material off the planet is going to be a huge headache, with no mass drivers or laser launch systems. Plus, demand would drop crazy fast once Earth's market goes offline. But, if there were sufficient warning, would there be a sharp rise in demand for orbital construction and materials as people sought to leave? It could be a trigger for a strong space economy. Regarding the impactor, how plausible is it for a ~40 km rock hurtling in at >50 km/s to remain unnoticed till a few years before impact? It would definitely be an ELE, but I doubt at least some (~100 million - 1 billion) people wouldn't survive, at least, initially. Also, what would be our prospects of deflecting a multi-trillion ton rock? How feasable would such an impactor even be? It'll likely be more ice than rock, at its velocity, so would an iceball/comet complicate matters? Can nuclear weapons ablate enough ice fast enough to deflect it? Chemical drives are out, since there's no way they'll be able to match velocity - can nuclear/nuclear-electric drives make it there fast enough? Can a few puny ground-based GW laser-launch systems ablate the ice/rock fast enough? Can laserstations be built around Mercury fast enough, with almost no existing infrastructure? Lastly, how bad will such an impactor be, considering its fairly high impact velocity and energy (~160 YJ / 38.4 Petatons of TNT / 6.6 times the maximum postulated energy of the Chixculub impactor)? The Russians actually have a program for anti-asteroid nucleair missiles. The basic idea is you deflect large asteroids (the larger they are, the earlier you have to hit them for sufficient deflection, but the earlier you can detect them) and shatter smaller asteroids and have the fragments burn up in the atmosphere. Hitting and deflecting the asteroid is not the issue. We currently have those capabilities. The main question is whether we can detect an asteroid early enough.
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Post by The Astronomer on Apr 28, 2017 10:21:57 GMT
Casabas are tuned for long range engagements; fractions of a light second for higher-end devices. They sacrifice total energy efficiency for a more focused jet for effectiveness. Meanwhile, the stereotypical Orion Pulse unit is designed to detonate within a few hundred meters of the target. Much more of the energy reaches the target, but obviously you have little standoff. SevenOfCarina Hm. With such limited industrial tech, and assuming hab tech is likewise hamstrung, I would forsee most pre-collapse colonization occur around Mars or the Jovians. Venus is easy to live on, but extracting industrial resources from it is going to be hard, thus crippling any attempts at industrial expansion. Unless you have a giant megacorp based on Venus that coerces Belter clans to make shipments of industrial metals towards Venus, aerobraking into Low Venusian Orbit to save dV... Better yet, Venusian megacorp diverts entire asteroids - electric drive plus nuclear power. No aerobreaking for this kind of stuff though, the risk of catastrophe is simply too high. You can probably use simple nuclear shaped charge for asteroid redirection/destruction. This is, except if lasers are installed on this rock, then 1) casaba, 2) NSC
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Post by SevenOfCarina on Apr 28, 2017 11:02:36 GMT
I think there's a misunderstanding here. I'm not proposing that someone diverts an asteroid to hit Earth. I'm proposing that some fairly large comet Earth-crossing comet, on its foray into the inner system, just happens to intersect Earth's orbit when Earth happens to be there as well. Asteroid-diversion, if it were feasable on a massive scale, would mean that a move like diverting an asteroid would be instantly detected, not accounting for light-lag. And there would be safety nets. This impactor is natural, and any diversion attempt would be to stop it hitting Earth.
As such, belt mining is fine. But asteroid diversion should either require a lot of time, or a lot of resources and effort.
Regarding Venus, there isn't much full-scale colonization - more a bunch of idealists in floating habs who are barely eking out a living. No significant population here. But is it really that hard for automated mines to exist on Venus? If there is no significant active volcanism, the surface is likely a treasure trove of metals.
With lower-end drive tech, the Jovian system is years away, assuming Hohmann minimum-energy transfers. Would colonization be still feasable?
And regarding drive tech, I'm imagining that interplanetary propulsion would be done mostly through the use of NTRs, and, to an extent, chemical rockets. Aluminum-Oxygen rockets would be the go to on Luna, Methalox on Mars, and probably Hydrolox on Venus and elsewhere. Orbit to orbit should be dominated by methane/hydrogen NTRs, likely pebble-bed designs.
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Post by The Astronomer on Apr 28, 2017 11:05:51 GMT
I think there's a misunderstanding here. I'm not proposing that someone diverts an asteroid to hit Earth. I'm proposing that some fairly large comet Earth-crossing comet, on its foray into the inner system, just happens to intersect Earth's orbit when Earth happens to be there as well. Asteroid-diversion, if it were feasable on a massive scale, would mean that a move like diverting an asteroid would be instantly detected, not accounting for light-lag. And there would be safety nets. This impactor is natural, and any diversion attempt would be to stop it hitting Earth. Natural asteroid velocity is around 5-10 km/s, in case if you're wondering.What are the dimensions and mass of this asteroid?
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Post by bigbombr on Apr 28, 2017 11:11:47 GMT
I think there's a misunderstanding here. I'm not proposing that someone diverts an asteroid to hit Earth. I'm proposing that some fairly large comet Earth-crossing comet, on its foray into the inner system, just happens to intersect Earth's orbit when Earth happens to be there as well. Asteroid-diversion, if it were feasable on a massive scale, would mean that a move like diverting an asteroid would be instantly detected, not accounting for light-lag. And there would be safety nets. This impactor is natural, and any diversion attempt would be to stop it hitting Earth. As such, belt mining is fine. But asteroid diversion should either require a lot of time, or a lot of resources and effort. Regarding Venus, there isn't much full-scale colonization - more a bunch of idealists in floating habs who are barely eking out a living. No significant population here. But is it really that hard for automated mines to exist on Venus? If there is no significant active volcanism, the surface is likely a treasure trove of metals. With lower-end drive tech, the Jovian system is years away, assuming Hohmann minimum-energy transfers. Would colonization be still feasable? And regarding drive tech, I'm imagining that interplanetary propulsion would be done mostly through the use of NTRs, and, to an extent, chemical rockets. Aluminum-Oxygen rockets would be the go to on Luna, Methalox on Mars, and probably Hydrolox on Venus and elsewhere. Orbit to orbit should be dominated by methane/hydrogen NTRs, likely pebble-bed designs. I was pointing out the asteroid deflection capabilities in a purely defensive role: deflecting an asteroid already headed for Earth seems feasable. This means that a cataclysmic impact is only probable if we detect the asteroid too late.
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