wumpus

Which is one of the reasons KSP uses a planet with unobtanium density, to keep the player from getting bored. You can keep the audience involved with a multi-day "falling from Moon orbit" in Apollo 13, but the Enterprise is a sturdier ship. Better get the whole process done quickly. A better question is why the Enterprise orbits planets at all? Simply parking over one spot requires a ton of delta-v, but that is still minimal compared to what the Enterprise is almost always pumping out. Presumably sci-fi fans were very familiar with orbits in the late 60s and expected orbits around a planet. Travel beyond the Earth could be done however they wanted.

From where? I'm assuming that they will be more than capable of launching satellites, but they seem to have even more problems dealing with customers than Spacex. A "low profile" space program certainly has advantages (just ask the Soviets/Russians), but it harder to get sales when you keep your customers in the dark (ok, they probably aren't to crazy about "Elon time" either). Selling an engine to ULA sounds like a *huge* cash influx, but I'm less convinced it will go through. I remember a co-worker with an A&R license (a license to repair airplanes, although said co-worker also had a pilot's license. Not sure which school this lesson was taught at) who was asked in a class 'what makes airplanes fly'? After a bunch of answers involving aerodynamics and lift, the correct answer was "money". In practice, that is the most important figure in keeping an airplane aloft. I suspect the main difference for spacecraft is how many zeros have to be added to the check. Ask John Carmack how that works for mere "multimillionaires".

How much different is it from Spaceship Two? I assume it won't allow the wings to be stuck in the wrong position without a few overrides (unless the computers agree), and I'm sure they couldn't repair the old one, but anything else different?

I remember reading about a movie (I think it was "Poltergeist", long before the CGI era), that had a single line "and then the house imploded". So they had to carefully build a scale model house on top of an industrial-sized disposal, and then suck the house down and grind it up faster than it collapsed. Very expensive line of text.

One of my favorite authors is L.E. Modesitt Jr. released "Solar Express" in 2015 (KSP 1.0 dropped in 2015, I don't know the lead time for novel, but it is considerable). Without KSP I would have only groaned at "partial space elevators". After playing KSP, I pretty much groaned at every plot-significant orbital mechanics failure in the book. Since it primarily centered around "torch-ships" (high acceleration ships that go faster than Hohmann), it was unlikely to be so blatant to anyone before the "started playing KSP" on the "knows orbital mechanics vs. time" graph. I may have mentioned it before. But literary sci-fi has always been held to a higher standard than TV or movie (which tends to have all the scientific rigor of Star Wars).

While the math might be unassailable, expect to find tons of assumptions about the shapes of random variables there. Even worse, there exist plenty of controls (all other species) that are summarily ignored out of some "human exceptionalism" refusal to check the data. There is a reason that science typically demands experimental proof (regardless of how far the disciplines of theory and experiment may have split). Doing math and expecting it to match the physical universe without understanding the actual mechanisms leads to situations like this. Bayes theory gives you a big step up in developing inferences if you know a good deal about a non-independent random variable. If you are dealing with "beyesian" solutions that aren't concerned with accurately calculating said random variables (as well as the degree of independence: something often quite difficult), you can safely ignore their claptrap. There simply wasn't attempt to check this type of thing, which is why it is such a crank paper. You could check it against other species and find out your methods are useless (species become extinct because humans (or changes caused by humans) destroy their habitat. Is has nothing to do with how many individuals have lived since the species evolved. Or you could calculate rigorous error calculation on the known accuracy of your assumptions. Since all of them are purely assumptions, watch your error hit +/- 100%.

Multimeter's come in two varieties: Calibrated Flukes for formal testing, everything else for troubleshooting. Many shops like to use only calibrated Flukes, just to make sure that nobody grabs the wrong one during test (the costs of using the wrong one outweigh the cost of keeping a Fluke calibrated), but if you don't need formal paperwork for your testing the "Harbor Freight" special is likely good enough (maybe somebody knows of "in-between brands", but I doubt there is enough of a market to bother). - I have a 30+ year old Circuitmate (had to dig it out to check the name). A Chinese co-worked was impressed (I'm sure it had *zero* name in the states when my parents bought it for me), but I suspect that "Circuitmate" might be almost as expensive as Fluke (or might not and just be riding on the old name. All I know is that it still works after all these years).

The problem is that the Carter hypothesis claims the opposite. That looking at the numbers of humans (generally limited by age of species), we can determine humanities lifespan. It wasn't obvious that age of species was irrelevant to extinction until the anthrocene mass extinction gave us a ton of details on species going extinct. And now we know it is irrelevant. So the Carter hypothesis is invalid.

The entire game is designed to be played without mods (although many think delta-v should be included in the game). So career mode? Science mode? Sandbox mode is still better, but here mods excel. Expect to want to have a spreadsheet running that computes delta-v. It doesn't need to be complicated and you can probably use google sheets or some other mobile spreadsheet if you are on a console without a computer nearby.

It is big enough to have its own name in MMO circles: ""wagro". Google that for hints (knowing MMO players, it probably involves moving to the couch).

Is there any context for those of us clueless about Russian internal operation? Does he have a reputation for milking a cash cow with zero interest in further development or otherwise killing the goose that lays the golden egg? I can't believe that Russia would shut down Soyuez, but halting further development (along with more QA issues) is easily believable. It might need to be a simple link to avoid the "politics" issue.

You'll notice that none of your objections have anything to do with how old the species is, and the same issues ("don't have good numbers") pop up in the Carter "methodology".

You'll note none of the limits are on power extraction, although I did use some very real limits on efficiency of said extraction. What I *can* point out is how much surface area you need to extract a given amount of power an maintain thermal equilibrium. If you extract more power for a given surface area, your temperature will continually increase. If you assume a sufficiently long space battle, at some point the spacecraft will melt. This works fine if you are on the surface of a planet and can simply take "the water" from a river and return same. This is also how you compute for open loop. In vacuum, the only way you are going to cool "the coolant" is by black body radiation and the only thing that matters are temperature, surface area, and albedo. Albedo is going to be black (ideal), temperature is a critical factor in power extraction efficiency, and you can then solve for the ideal temperature for the smallest amount of surface area, and then finally compute how much surface area you need for the same power. Mass never shows up in the equation, at least until you have to physically construct the radiator of given surface size and uniformish temperature. I wouldn't be surprised if only open loop cooling mattered in space combat. It is ghastly inefficient, but if one side can cool itself while heating you beyond what any feasible radiator can handle, it will win regardless of how inefficient its use of liquid hydrogen is (it can also maneuver at >1000Isp with a hydrogen open loop). But I was somewhat astonished that no amount of E. E. doc Smith space opera technology could beat the radiators on the ISS by more than about an order of magnitude (in size, not mass) [also I assumed they can dissipate max power at 200K. The temperature is too high, but they really need to dissipate max power*(inefficiency of the solar panels), so the final figures are probably close enough]. If you win the "first round using open loop cooling", there won't be a "second round using radiators". The point is to never ignore cooling. You can scale up power generation easily enough: kilopower shows how to build a fission reactor in space. Scaling the power generator up could be as simple [for those with exactly the right clearance and need to know] as copying submarine reactors. Cooling such a beast that always submerged in water with same constantly available is another story, and any technological improvement is pretty much limited to increasing surface area/mass. I also don't think anybody has ever worried about the [power] efficiency of a nuclear reactor (obviously excepting the few designed to be in space), so that is a pretty new thing, but if you can get near Carnot efficiency out of coal and natural gas, doing same for nuclear doesn't seem to far a stretch. You can handwave anti-matter all you want, but it will still have the same thermal efficiency of any other heat engine, and still need to be cooled with the same black body radiation that the ISS uses (but presumably you can handwave in unobtanium leaf radiators). I find it odd that you can accept limitations on a lens (although I don't *think* they're fundamental), but not realize the fundamental limitations of heat engines and cooling requirements in vacuum.

Wires don't like to store charge (which is why they are good at moving it around, it doesn't stick to them). Plates like charge. You'd only manage to cover the silhouette of the wire with charge, which doesn't have much point. Wires *will* store current (and have measurable inductance), but I've never heard of anyone worrying about the capacitance of a wire (although it has to exist in transmission lines, but has no real effect other than establishing an impedance to go with the inductance).

I still think the problem assumes the wrong shape of a random variable. The assumption appears that new species come and go, while old species stay around forever. I've heard that while this sounds likely, in practice the odds of a species go extinct has little to do with how long they have existed. A more likely issue is how many niches/environments they can survive in. Quick question, how old do you think the various species are on this list: https://en.wikipedia.org/wiki/List_of_threatened_sharks Humans are bad at probability. Unless *all* the models are explained, and the probabilities worked out, there is little reason to believe some random internet hypothesis (this even include more credited cranks who do well fooling experts in stuff outside of their field).

Wire doesn't form a capacitor, but perhaps two high resistance wires (megaohms or such) keeping two capacitors apart might be what you are thinking. I still doubt that such a design makes sense outside the Earth's magnetic field. Do probes to Jupiter's moons us electromagnetic propulsion? It is said to have a beast of a field, although you'd presumably need plenty of non-magnetic propulsion to get there. I know Mars doesn't have such a field, does Venus? It would at least allow a slingshot between Venus and Earth using only electromagnetic propulsion.

Anyone know if SpaceX has Bob Fitch as a consultant?

The theoretical limits are pretty easy to calculate. The maximum possible efficiency of your power generator is limited by the Carnot cycle limit (and this actually limits real power plants, and even some research car engines are approaching it). Efficiency<1-(Tc/Th) where Th is the heat of your steam (or whatever) going into a turbine (presumably a combined cycle). Assuming using Tungsten-Halfnium-unobtanium alloys throughout, this could be somewhere between 3000-4000K. Tc= the temperature of your heatsink (in Kelvin). Note that for ISS, this is less than 200K (you could presumably generate power for the ISS at 93% efficiency). Blackbody radation increases at the fourth power of temperature. So if you want to produce massive increases of power, you could presumably have the same size radiators and replace the ammonia with molten iron of something and have an efficiency of 10% and have the radiators at 3600K and the steam at 4000K (ok, this assumes your generators and lasers are 100% efficient, but still). This gives you a 324 fold increase in the amount of power you can produce with the same sized radiators. I optimized this a little more and came to the conclusion that Th/Tc should equal 3/2 and that for a Th of 4000 you would get 500 times the power over ISS using the same sized radiators (with an efficiency around 33%, but radiating a bit more than a third as much). The ISS radiators are about 1/10th the size of the solar panels, and not visible from any view directly facing the solar panels (what most pictures show), I'll use this for a "heat sink area unit" for theoretical spacecraft. REALITY CHECK: This assumes theoretically ideal turbines crafted out of unobtanium (to withstand 4000C), impossibly perfect lasers, and equally impossibly perfect generators (it doesn't spare any heating back from the lasers, and I doubt that such an equation will fit on the envelope used for the above). And you still have to deal with radiators only a couple orders of magnitude smaller (per Watt) better than a space station lifted into orbit in the 20th century. So for an *absolutely perfect* system (optimzed to reduce the heatsink), you get ~60MW per ISS-sized-heatsink. These are fundamental physical limitations and the only ways around them are open cooling cycles, matter that remains solid at 4000K, or perpetual motion machine. No amount of other tech will change this. There's a reason I want to fire on the heat sinks. Note this limitation is unlikely to be an issue outside of deliberate attack. It places no bounds on the radiators aside from shear size. You could presumably use gold leaf for the majority of you heatsink (not gold, you need something that won't melt at 2600K). It is only when you need something that can endure deliberate attack does the issue of raw surface area become an issue. Note that I suspect that with tech in barely doable (in parts, not all at once) 21st century tech we could bump this up to 30MW per ISS heatsink, but after that the asymptote gets *steep*. I'm guessing that any "missile based" laser will fire only briefly and use some sort of open cooling scheme. Open loop cooling works great if you need high-Isp "flanking speed', but also has the same tyranny as the rocket equation (bring *lots* of mass). Liquid hydrogen gives you great Isp, but little cooling. I suspect things like tungsten, halfnium, and depleted uranium (or just spent fuel rods) would be good for open loop cooling.

Flanking once battle begins should be effectively impossible (for the means stated). The real question should be if you can hide a ship/drone/mine with sufficient power to fire an effective laser (if only blow away heat sinks) at laser range distances. Like many battles, the whole thing would be won or lost before the first shot is fired (granted, that was your thesis as well, but I suspect position is at least as critical as numbers). Don't forget the power supply when determining the total efficiency: if you are using a fusion (or other heat-based engine) Carnot will not be friendly to high temperature heat sinks and your efficiency will plummet (modern power plants are near ideal at ~62% efficiency, but they typically have available water for heatsinks. Even with these high efficiency your overall "nukes to laser" efficiency would be less than 50% with 80% efficient lasers and 60% efficient fusion generators. You aren't getting 60% fusion generators with "liquid droplet or currie point" radiators. It is entirely possible that futuristic navies may have to forsake anti-matter power plants and limit themselves to fuel cells, and campaigns will make stopping at tenders for oxygen and hydrogen as critical as "coaling" was before the nuclear age. All this means that any means to add heat to the heatsink will effectively neutralize the ship. Also, those radiators have to be *big*. They might be obscured in one or two directions (requiring the ship to be flanked multiple times before your batteries bare on a target), but it is an amazingly vulnerable spot. And while flanking may be effectively impossible with the warships themselves, missiles may be able to "flank" (with ablative gas streams in front of them or ablative covering) in attempts to get the missiles to flanking areas to send some sort of heat (their own lasers? incendiaries? Thermally hot nuclear waste? Solar reflectors?). You mentioned "armor" and "hiding behind". I'd be very surprised if such a warship couldn't be designed sufficiently long and this and with ablative armor at the fore that could withstand long distance laser fire until the crew died of old age. Combat would be similar to submarine warfare where the sub would point toward (or away from) surface ships to effectively become invisible. Only when flanked and the side exposed is a sub likely to be heard by SONAR. It isn't so much that flanking attacks are effective, just that head on attacks are pointless (making any "barely effective" attack far preferred). Considering that "built along a single spine" is how humans currently build large spacecraft (see the ISS, which I'd expect any transmartian habitat to resemble), this shouldn't be unexpected. Granted, the way drones are heading I'm not sure I should assume a difference between "warship" and "missile". I suspect that in modern naval warfare (I basically built hardened IT for the Navy, not anything that went "bang". This is mostly speculating from old Tom Clancy leaks) "underwater drone", "torpedo", and "mine" are only different in how they are deployed, they are likely converging on very similar designs.

Just because they aren't holding the nozzle, doesn't mean they aren't there. At least all the film of astronauts boarding a space ship, the ground isn't *completely* empty of people (the rocket will go up soon, so they have to leave. But for Apollo missions they might have an hour).

Radiation doesn't mean it has the right properties to build a bomb/fuel source. I also doubt it is the right type of neutron source to enrich such stuff it you had it in space. To be honest, I'd classify spent reactors on *Earth* to be so far in the noise as to not bother about* (I'm fairly sure that the US has emitted more radiation than Japan has since right before Fukishima by using coal power then they ever let loose through direct atomic failure). Who has access to them might be key, not so much the danger of the reactor to anybody directly. *Leave the fuel rods in water for a few decades, then glassify and stick in completed [abandoned with known safety standards] mines. End result may well be safer than solar panels, wildly safer than solar, let alone fossil fuel. WARNING: the economics of nuclear power pretty much makes this pointless, even if the political factors can be overcome. The lead time will simply kill your program every time.

Of course, laser weapon will take an unbelievable amount of power to fire, and it is unlikely to manage 50% efficiency from fusion reactor heat to laser output. This means that you need some massive heat sinks desperately dumping all your heat. You might manage to do some internal tricks to limit huge arrays of cooling fins from being unfurled, but you will quickly have to make a decision to cut the fusion power plant or unfurl the heat sinks. The moment you unfurl the heat sinks you are going to have difficulties building an array that can't be quickly counter attacked by anybody attacking from a different direction to the original attacker (or whichever direction the ship tries to hide their heat sinks from). Lasers and optics are only a small part of this (and all they show you is that they don't work well). *Powering* those laser is key, and dealing with the waste heat is even more important: you don't want to give your enemy a larger target (although you may have to, there are only so many ways to emit heat in a vacuum). The key here is multiple directions of attack. The Navy that does the space equivalent of "crossing the T" will win, while the massed fleet will be firing into safe targets. It is by no means certain that this can be planned in advance. I included that tiny quote as the real problem with spacewarship design. If maneuver is important, you need the mass of your heat sinks as thin (and thus as mass-efficient) as possible. But you don't want to have them vulnerable to someone keeping a laser on them for any significant length of time (seconds? milliseconds? who knows). From at least one direction those arrays will be vulnerable, and if they are cooling a magic power plant [presumably fusion, but could be anything up to and including antimatter] they will have enormous amounts of area. Note: I've designed electronic equipment for the US [wet] Navy. You'd be surprised how much MIL-STD810 (harsh environment testing requirements) comes up simply due to power consumed and having to be cooled. And that is on a Navy that can take arbitrary amounts of cool liquids from the ocean and pump it through heat exchangers. Don't ask how much it is on the mind of a [real] star wars design engineer who designs for use in vacuum.

Another aspect to notice is that NASA's safety philosophy is largely PR based. You put the astronauts in last because to avoid having the rocket explode on you while they are sitting on top, if it blows up during fueling (regardless of how many techs are killed) it isn't such a big deal. While this made all kinds of sense when launching rockets was a cold war PR stunt, I'm not sure it is what we should be using. Space X insists on fueling the rocket *after* everyone but the astronauts are in a bunker.

Last I heard, the chance of any species to go extinct was pretty much a constant. Unfortunately, I can't begin to remember where I learned that little bit (the author of my lost source seemed to agree that it was far bigger than the evolutionary biology community thought at the time). If this is true, it pretty much kills the Carter "logic". Trying to sort historical extinction from human caused extinction is pretty difficult, although there is little reason to believe that humans are wiping out newer species than old ones (grasses are pretty new and doing quite well in the anthrosene).

If you have a reactor, I'm pretty sure you would find it more useful to dredge Iraq war battlefields for depleted uranium. If you don't have a reactor, spent fuel isn't going to help you much (and you'd need the centrifuge). That's not to say that I'd be all that happy with potential terrorist playing with spent fuel: see Randal Monroes' final comment about "swimming in a spent fuel pool here: https://what-if.xkcd.com/29/ You could always use the same to build a "dirty bomb", something otherwise mostly harmless that has been turned into a media/military-industrial-complex boogeyman (at least in the USA) such that setting one off will certainly cause significant death due to the stampede to escape it (ok, not so harmless. But you are far better off sheltering in place near the explosion than being in the stampede). It might make a good sci-fi story about Earth refugees that grab a few of these before leaving for elsewhere (or possibly revolting space colonies sneaking in and grabbing the nukes). It may take awhile to get things going, but then they should be ok. You get just how far in the future it has to be for it to be a problem.