Geschosskopf

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  1. Orbital solar collectors can't avoid the dark. If you put them in geostationary orbit so they can connect to the same ground station, then they'll be in the dark a some amount of the time. If you put them in any other orbit, they'll not only be in Earth's shadow some of the time, but you'll also need long chains of ground stations all around the world under their paths. Ignoring the diplomacy needed to allow such sharing, each such ground station is a discrete target requiring a pretty tight beam and the ability to switch it rapidly from 1 station to the next without scorching the space in between. Hmm. I just cooked my supper with microwaves running on 110V and less than the 20A the associated breaker trips at. And that's fairly weak even by household standards, which includes HVAC, clothes dryers, etc., but is still enough to burn animal and plant matter in seconds to minutes. So basically, it doesn't take much microwave energy for very long to be quite harmful to stuff on the ground. And therein lies the problem. If you widen the beam coming down, lowering its intensity to a less-than-popcorn setting, you need a vast forest of rectennae, each of which is only absorbing a less-than-popcorn amount of power to the grid. And each is a discrete entity so all the photons that pass between them are wasted, doing nothing but cooking whatever's there. This doesn't seem worth the bother for a number of reasons---cost, complexity, resistance loss, waste of most of the wide beam you paid to put in orbit, etc. Not to mention the EMP-like effect and RFI this would create all over the target area. To avoid these problems, you have to concentrate the beam, which creates other problems. Because the country with the big lasers obviously wouldn't allow foreign powers to position conventional artillery within its borders close to said lasers. We already have. If's called "we ain't doing that". Anybody who takes a step in that direction MUST be viewed by everybody else as potentially making a world-dominating weapon, because it could easily be used as such. This is why we don't have bases on the Moon. It's better not to go there than to give us something else to fight over. I mean, look at all the hassle currently going on over Iran's nuclear program.
  2. It'll be interesting to see how being based at Woomeranga influences things. Good luck!
  3. And particle beams don't work that well through the atmosphere, so the beam originates somewhere in vacuum. Which means it can at least obliterate every satellite its owners don't like. But, you've still got to concentrate the energy into a beam (to prevent most of the power from being wasted) and aim it at a relatively small spot on the ground (where this beam can be put to use). And it has to be considerably more intense than sunlight or ground-based solar panels would do just as well and there'd be no point in putting the panels in orbit. So no matter how you slice it, you've still got a very power stream of directed energy aimed at Earth. Unless that firepower is also equally powerful lasers, it'll be too late to stop anything.
  4. It's not the ease of making it, it's the ease of using beamed power as a weapon. Lets say you only fuel an Orion out beyond the Moon. The skipper goes rogue and starts shooting nukes at Earth. They'll be several days in transit at least, plenty of time to shoot them down before they arrive. With massive lasers, you can just reorient a mirror here and there, and POOF, instantly vaporize any target you want. No way to stop that. This accidentally happening has always been a major downside of putting massive solar collectors in orbit to beam power to the ground. If the platform wobbles even a little,, the beam will laser-etch a lot of real estate around the ground station.
  5. A couple points I haven't seen mentioned on this yet. First, when setting up transfers by hand, it's often easier to set up any correction node once you're outside Kerbin's SOI, just due to how patched conics display. And, when you're still in Kerbin's SOI, any up/down adjustments you make are relative to Kerbin, when what you're ultimately needing is relative to the sun. This can sometimes be confusing, so it's generally easier to wait until you're outside Kerbin's SOI. Also, prior to the relatively recent addition of the maneuver node editor box in the lower left corner, the interface often made it very difficult to plot correction burns while you' were still close to Kerbin. You had to focus on the target planet to see your trajectory in its vicinity but the node was all the way back at Kerbin where it was hard to manipulate. So this is often why folks would do their corrections like 1/2way to the target. They were outside Kerbin's SOI and close enough to the target to manipulate the node while focused on the target. Experienced players, knowing this was how you had to work around the limitations of the interface, would bring a bit more fuel than necessary to cover any inefficiencies this method caused. Nowadays, however, with the node editor, these concerns don't matter. The other thing to keep in mind about waiting to the middle to do the mid-course inclination burn is that the further you get from Kerbin, the more vertical distance there is between Kerbin's orbital plane (where you are) and the plane of the target. Thus, your ship has to go up or down at a steeper angle the farther you are from Kerbin. Which means, when you encounter the target, you'll have more inclination relative to the target because you'll be approaching it at a steeper angle from above or below. If you're wanting to get into an equatorial orbit at the target, then yo'u'll have a bigger inclination change to do once you get there than if you'd done the en route plane change closer to home. If you're not concerned about this, then it doesn't matter. My rule is only use nukes if there's no other way to get the necessary dV. The problem with nukes is that they lack thrust and if you're leaving from LKO, you need a minimum TWR of 0.75 or so. This is to keep the transfer burn down to 5-6 minutes AT MOST, or about 1/4 of an orbit around Kerbin. If the burn takes any longer, you lose beaucoup efficiency to cosine loss and might even clip the atmosphere. If you've made some massive mothership, sometimes you have no choice but to accept a very low TWR and a stupidly long burn. In such cases, you'll want to start in a higher orbit with a bigger radius, so the cosine loss is much less. But then you lose out on the Oberth effect. You can also sometimes split a long, low-TWR burn over 2 orbits, but this has its limits. The 1st orbit can only be about 1000m/s or you'll leave Kerbin's SOI instead of coming back around to finish the burn. Also, going out to the vicinity of Minmus on the 1st part of the burn will make the 2nd half happen a week or 2 later, which throws off your carefully timed transfer window, so you'll need a bigger mid-course correction. So all in all, keep your transfer burns 5 minutes or less. That's plenty of time to debeer/rebeer without having a long wait staring at the screen
  6. I was unfamiliar with the liquid core versions so point taken But using molten salt to cool a solid core (also called MSRs) have been around a long time. Some Soviet subs reportedly had them. Yeah, this type of reactor can't be a torchship because the fuel isn't macho enough. The fuel properties you outline are the exact opposites of what you want in a rocket engine. It might work well to power a VASIMR, though.
  7. To be more precise, the game doesn't care which edge of a wing part faces the wind. It can be any edge or corner, the result is the same. Also, the wings have a symmetrical section so have no top or bottom. So, in terms of building a wing out of multiple wing parts, you can orient the parts however you want to get the desired overall shape. That said, wing orientation matters in the pitch axis. Due to having symmetrical sections, wing parts can't create lift from an airfoil section so have to be at a positive angle of attack to the airstream to create any lift. You can either build this into the whole wing, putting it at a slight angle to the fuselage axis, or you can fly slightly nose-up.
  8. Again, um.... no. The hard thing about conventional reactors was designing a controllable core that wouldn't explode or melt without a long chain of unlikely events happening. Once they had the core design, everything else was existing technology, or nearly so. For instance, in a PWR, the most extreme water conditions for the coolant are about 2200psi at about 650^F. This is actually easier to handle than the 1200psi, 950^F superheated steam then being made every day by the thousands of standard oil-fired naval boilers of the 1950s because steel starts getting soft above 900^F. (red heat), as any blacksmith can tell you. So yeah, the PWR had about twice the pressure of a 1200psi steam plant but regular steel was better able to withstand it because it wasn't hot enough to get soft. Thus, the PWR didn't need new materials or alloys invented, which was the case for the 1200psi steam plants, it just needed thicker walls of whatever existing alloy was cheapest. The NSWR has nothing in common with any of this, however. The operating principle of the NSWR can be summarized as having a continuous nuclear explosion going on in the combustion chamber, obtained simply by pumping nuclear saltwater into it. It has to be an explosion because otherwise you're just making relatively low-pressure (because it's uncontained due to the open nozzle) steam like with the non-explosive NERVA. Otherwise, the NSWR wouldn't offer the advantages over the NERVA that Zubrin claims. So, it's a given that having enough fuel in 1 place to make this continual explosion happen means you can't store it in 1 place in that quantity. This is why the fuel tank has to be so unworkably complex, essentially being a giant conventional nuclear reactor core you can't even use, just lug around. Basically, with the NSWR, Zubrin envisioned a machinegun version of the single-shot Hiroshima bomb. In that bomb, you had 2 separate sub-critical masses of uranium far enough apart not to set each other off. An actual gun fired 1 of these masses into the other, resulting in the big boom. Hence the liquid form of the radioactives in the NSWR concept. Just keep spraying this mixture into an environment where the neutrons can do their work unimpeded and voila, constant explosion. Setting aside the dubious ability of any known nozzle material other than metastable neutronium to withstand such "mundane" forces as a continuous nuclear explosion going on within arm's reach, you have to consider the back-pressure that such a continuous explosion would induce up the necessary myriad of fuel tubes (to prevent the explosion from happening in the tanik) leading into the combustion chamber. Which tubes, as mentioned above, have to be skinny to avoid the fuel going critical even under zero-G. That's without considering the centrifuging the dissolved uranium salts would experience due to the thrust of the running NSWR engine and the resulting mixture imbalances in the combustion chamber. But even if this can be overcome, you still have the back-pressure from the continuous nuclear explosion which the feed pumps have to overcome in the the volume required to run the engine despite the friction loss inherent in long, skinny tubes, And all this pressure somehow handled without rupturing the fuel tubes just from the feed pump pressure. It simply can't work. Zubrin is either demonstrably insane or crazy like a fox in trying to get rich off preaching to the gullibility of the masses. You can always see the madness in his eyes on TV, despite the multiple takes and edits before the show airs. And he's always preaching, never discussing. He always preaches his demonstrably incorrect theme that colonizing Mars will save humanity by making us a 2-planet species, and that achieving this goal is only a few legislative votes and a couple of "minor" tech advances away. The multiple fallacies inherent in his sermons should be appallingly obvious to anybody not hypnotized by his crazy eyes. Colonizing Antarctica would be several orders of magnitude easier than colonizing Mars and would have a more positive result on the human species, but nobody is preaching for that happening because it's obviously a stupid thing to do. Colonizing Mars is therefore even stupider. All the extra effort required there as opposed to Antarctica won't make us a 2-planet species, it would make us (at best) 1 huge subspecies on Earth with a tiny, troglodyte, utterly dependent subspecies on Mars. But ignoring these obvious facts, Zubrin concocts utterly unworkable schemes like the NSWR to keep deluding the delusional, which includes himself IMHO. I wholeheartedly agree. The allure of the NSWR, which has beguiled so many who haven't thought it through, including Zubrin, is that it relies on a SUBSET of the well-known properties of uranium and water, without considering the rest.
  9. Um, no.. Not. At. All. The NSWR has NOTHING in common with a normal (or even molten salt) reactor, other than they both involve uranium. Thus, the challenges are ENTIRELY different. In the conventional reactors you mention, the uranium is solid, in the fuel rods, and doesn't move. The pressurized water or molten salt is merely coolant, absorbing heat from the solid core and carrying it away to keep it from melting. As this fluid circulates through the fuel rods, it picks up bits of radioactive solids so is usually not the actual working fluid---otherwise you'd contaminate the turbines, which would complicate maintenance. So instead, the coolant goes through a heat-exchanger to pass the heat on to the actual working fluid, which is water in a separate set of pipes. This water turns to steam, spins the turbines to make electricity, condenses, gets cooled in the big towers, and back into the heat exchanger. A NERVA is essentially a conventional reactor just like the above. You still have a solid fuel core around which you circulate a fluid to carry away the heat. The only difference is that the cooling system is total-loss. The heated fluid is allowed to expand out the nozzle to provide thrust, instead of circulating back through the core. The NSWR is completely different in basic concept from any of the above. It has no solid fuel core around which a fluid passes. Instead, the uranium is dissolved in the water. That's where the "nuclear saltwater" part of the name comes from. This water is stored in such a way that the uranium in it is prevented from reaching critical mass until it enters the combustion chamber. Once in the combustion chamber, the uranium heats up, boiling the water and shooting both itself and the steam out the nozzle. This sounds all very nice in theory, but the rub is storing the nuclear saltwater. You can't have it in a single big tank or the uranium in it would go critical in the tank, just as it does in the combustion chamber, and the ship would explode. About the only way anybody can think of to store the fuel is in a great mass of very long, very small-diameter tubes made of and/or separated by some neutron-absorbing material. IOW, the fuel tank configuration would resemble the core of a conventional reactor, with the tubes of nuclear saltwater being analogous to the solid fuel rods, and the neutron-absorbing stuff between them being analogous to the control rods. So basically, the fuel tank itself (not the actual engine) would essentially be a nuclear reactor core in full SCRAM mode. Now think of what that implies for the ship just sitting still. First, there's the mass of fuel as uranium is heavy. Then there's the mass of all the neutron-absorbing stuff, which is also very heavy. And the whole thing is still giving off radiation and making heat even when the engine's not running, so needs both shielding around the outside AND its own cooling system to carry off the waste heat that will always be happening. And all this stuff has to be very small-diameter, which makes it both problematic to manufacture, hugely expensive, and not having much margin for the normal erosion of materials when exposed to neutrons. Also, if you build an NSWR ship in orbit, all the tankers sent to fuel it up will have to be build the same way, and have even more shielding because it'll be on the ground to start with. And of the tanker crashes on launch, you end up with a big pile of uranium going critical with no shielding at all. Now think about how this would work with the engine running. First, you have to come up with some system to force the nuclear saltwater out of the long, skinny tubes you have to store it in. This is going to take quite a bit of pushing because there'll be so much friction loss in the long, small-diameter tubes, yet the pressure can't be very high or the skinny tubes will rupture. And you'll need scads of such pumps, 1 for each of the myriad of fuel tubes., so way more weight and complexity. But if you do somehow get the engine running, you create thrust, which will cause the heavy uranium to be centrifuged down to the bottom of the tubes instead of remaining uniformly distributed in solution. This could result in the fuel going critical at the bottom ends of the tubes. At the very least, it will screw up the ratio of uranium to water, making it too rich to start with and too lean later. Now think about the maintenance problem of all this. All the tubes and the neutron-absorbing stuff will have to be replaced frequently because they'll erode. All those pumps will need frequent care, too. But the big operational problem is how to deal with fuel leaks. You have thousands of tubes, all rather long, no doubt made in multiple sections. They could each leak anywhere along their lengths. But they're densely packed so you can't access any but the outer layer of tubes. So, if you get a leak in one of the interior tubes, it'll be spraying uranium all over the area. The water boils away in the vacuum and you're left with uranium icicles, which will go critical as they're out of their neutron-absorbing sheaths. This will burn bigger holes in other tubes, allowing more uranium build-up, resulting eventually in the whole tank exploding. This is what makes the whole NSWR idea so crazy. The very property of the nuclear saltwater which makes it work (in theory) as a rocket fuel also prevents any workable way to store the stuff or transport the fuel.
  10. Thanks for checking. I have both MH and BG but, as per the installation instructions in the OP, I also have Making Less History. The Lua base actually works for launching, but not recovery. The main problem, however, is that once you launch a ship from there, and switch focus away from it, the universe implodes. I also just noticed another problem with the Lua base since the most recent KK update. The comms network no longer links to Rhode and its extra ground stations, but only to Lua's tracking center. This is very annoying. I'll try shutting down the Lua tracking station and see if that fixes things.
  11. Well;, you believe crazy Zubrin, I'll wait to see whether the justifiably skeptical, arguably saner people have to say. And as mentioned, even if the numbers ultimately say it could work in theory, and even if the politics get sorted out, there's still the immense practical engineering problem of simply building the fuel tanks at all, let alone making them even remotely safe from punctures in operation. These issues put the NSWR in the same category as drives that require the presence of a black hole or the like. Maybe possible in theory but utterly impractical to build.
  12. Horses aren't the best draft animals for plows and heavy wagons. The virtue of the horse is speed but not strength or endurance. Mules have much better endurance but less speed and variable strength depending on their breeding. Oxen have much more strength and reasonably good endurance but the least speed. Donkeys have good endurance but low speed and strength. So the best draft animal for the job depends on what you're pulling. Heavy wagons and high-resistance plows are better pulled by mules and oxen than horses or donkeys. Light carts and pack loads over long distances where speed is not an issue are best handled by donkeys, and heavier loads in the same circumstances by mules. Anything that requires speed is best done by horses, with more of them required if the load is relatively heavy for them. Of course, the wealth of the person plays a part, too. Perhaps as often as not, the wrong animal has been used for the job simply because that's all the owner had available. And all this ignores special climate conditions where other animals (camels, reindeer, elephants, llamas, etc.) might be in the mix or the only things available or capable, The Romans didn't use chariots in battle. In the civilizations around the Mediterranean, chariots had become obsolete centuries before with the advent of cavalry. But chariots remained part of their mythology, the vehicles which their by-now deified ancient ancestors had used to conquer their home territories. Thus, the Romans still had chariots, which persisted well into Byzantine times in the Early Middle Ages. They were the limousines of the rich and famous and they were also the NASCAR racers, very different from the LBA war chariot. The Roman quadriga was pulled by 4 horses instead of the 2 used by LBA war chariots so could only negotiate the widest streets or specially prepared racetracks. As a prestige vehicle, it never moved faster than the shackled prisoners and marching troops also talking part in the Triumph parade. As a racer, it only carried 1 unarmored driver as opposed to the 2 heavily armored warriors of the LBA war chariot, so was even lighter than its prototype and had literally twice the horsepower. I don't think any of this agrees with either archaeological or historical evidence. Riding horses was not mainstream for a long time after their first domestication. The earliest evidence for domesticated horses are their butchered bones, in large quantities, in the trash middens of Neolithic settlements where they ran wild and, later, in areas where they didn't.. Contemporaneous illustrations of horses as either riding or draft animals do not exist, nor is there any indication of the totemic reverence of the horse at this time, which was later such a feature of horse-riding cultures. That said, the Botai culture of Kazakhstan seem to have been riding bareback since about 3000 BC, although they rode to hunt wild horses for meat. It took a long time for the idea of riding horses to get from there to elsewhere, so was likely invented independently several times in other places. The mainstream use of the horse as a mount can be tracked by its appearance as such in art (as opposed to pulling chariots), its sudden totemic significance to those who owed their subsistence and military power to riding, its appearance as sacrificial burials with persons of importance, and the vast reduction in its frequency as kitchen garbage. This did not happen, in most parts of the world, until the Iron Age, slightly early where wild horses were more common. The horse collar was an Early Medieval invention as it is attested in neither archaeological remains (including tell-tale bone signatures on draft animals), nor contemporary written accounts, nor contemporary art, before then. The horse collar was better than the horse harnesses that had gone before but it by no means was essential to getting productive work out of the horse. The stirrup is more or less a contemporary invention to the horse collar. Neither Alexander's nor Caesar's cavalry had them and if they didn't, they definitely weren't mainstream at the time. Although hooking the barefoot rider's toes into the girth or simple rope loops date to about 500 BC, actual solid stirrups for booted feet, allowing the cavalryman to put is legs into his sword swings and to charge with a lance, aren't archaeologically attested until 200-400 AD in China and rather later elsewhere in the world. As to the printing press, sure, the general concept is as old as Neolithic/Chalcolithic seals Or even older, to Paleolithic handprint stencils on cave walls. But until Herr Gutenburg in the 1400s, EVERY printed or pressed thing was made by a monolithic carved block (or signet ring, or cylinder seal). which could only say the same thing regardless of how often you repeated it. This made printing/pressing only useful for signatures on documents or producing many copies of the same imperial edict to post up on walls all over the realm. You couldn't mass-produce books because each page would have required its own hand-carved block. This is why mass printing and mass literacy never happened until Gutenburg's invention of movable type, so that each page of a book could be set up quickly with no skilled labor other than proof-reading.