wumpus

If you can get up and do it again, it is a *great* landing. Breaking bones might not be such a good landing, as you wouldn't "walk away from it".

Wise colonists would have this before leaving Earth (or whatever location). Trying to keep the colonists on the ship might be difficult (of course with a multi-generational ship, getting the colonists to leave the ship may be the hard part). There is a fairly classic sci-fi story of colonists who didn't get a sufficiently complete zoo-technical report and killed off all the extremely dangerous predators: https://www.goodreads.com/book/show/899392.The_Legacy_of_Heorot

Mostly it would depend on how full the plane is. And I find it hard to imagine that this thing would displace large jets for any flight you wouldn't want to drive. Displacing longer car trips is possible.

Using the empty husk of a mined asteroid is an old sci-fi idea. The shuttle flew "backwards" orbiting. The engines weren't needed to land, and had a lot of mass. Using them as a shield for meteorites/orbital debris made sense (losing a windshield while flying "forward" would be a disaster). Similarly, flying inside the solar system you want to present a lot of mass toward the Sun. Ideally, bits without a lot of electronics or anything else that a solar flare might damage. You'd also need cosmic ray shielding around all inhabited parts. I'd assume that any "meteor shielding" would only be needed on the path of the eleptic. But I've never heard of any spacecraft being lost to such things, so I imagine that avoiding such things would be trivial, and you wouldn't bother with shielding and just maintain an attitude perpendicular to the Sun.

From what I understand, the "venom" is produced by symbiotes that live in the komodo dragons' dirty mouths. I'd strongly suspect that alien venom wouldn't be effective against Earth biology (and vice versa). The alien komodo dragon might easily pick up strains of bacteria dangerous to Earth critters. I'm fairly surprised that vultures and similar carrion birds don't have poisonous claws similar to komodo dragon teeth. Birds could work well with "touch and go" tactics and circle around until the prey dies. The catch is that a large venemous creature has to eat that much more to stay alive. A grizzly bear needs something like 1 square mile territory. A venomous grizzly would require a similar territory. But a venomous black bear would be just as lethal (to anything other than another venomous black bear) and require less territory (and spread faster). There would be evolutionary pressure to get smaller once the venom was sufficiently effective to hunt down moose (if moose was needed for food, which is unlikely).

I'd recommend sifting through Saturday Morning Breakfast Cereal for the physics of Superman. The comic I was looking for :https://www.smbc-comics.com/?id=2305 Presumably the "Fortress of Solitude" is orbiting inside of Mecury's orbit, and can focus sunlight onto Superman powering him up far greater than mere sunlight out at Earth's orbit. This allowed his parents (and the rest of Smallville) to survive his childhood/adolescence with less than full superpower (presumably he also had to save enough to get to orbit/sun-synchronous orbit/Mercury orbit and build the fortress). And while presumably Metropolis is a city that doesn't sleep, he can find times when he can leave to top off his power level.

If the "whole calculus thing was almost out of thin air", then why did Gottfried Leibniz invent it at essentially the same time? I'd recommend some of James Burke's "Connections" material to correct much of the "great man" theory of scientific/technical progress. And if it leads to study the rest of the history behind his shows so much that you see the real flaws they have, so much the better. To point out how rare the exceptions are, the only one I can think of is the invention of turbo codes. Error correcting coding had barely gone anywhere in 20 years, and then someone published a paper (and patented) a means of producing nearly theoretically "perfect*" error correcting codes. A few years later, somebody dug up a long-existing competing algorithm "LDPC" which even its creator didn't bother to put in "The Book" of error correcting codes as it was a theoretical exersize to produce near perfect codes, but considered it required far too many cycles to take seriously. Several decades later (long enough to prove patent unencumberance no matter whose patents you had) it no longer took "too many cycles". * "perfect" here means that with enough calculation and enough source bits you can produce a theoretically minimum number of redundant (typically called parity) bits that will perfectly correct the original. Obviously, it should be possible to create an algorithm that uses far less operations and thus be "more perfect", but communications companies are far more interested in what goes through those expensive frequencies they bought/leased than what is needed in the base stations.

Somebody would have to climb each tower and place pyrotechnics at each cable for a controlled demolition, all the while one could snap and whip around in arbitrary directions. Assuming nobody was around, this is far better. After the second cable snapped, any possibility of repair became extremely difficult (and apparently futile, as you'd be unlikely to get it sufficiently supported before today). Scott Manley has a video (of course. And probably one for today as well).

While this is true, the chance of failure goes up as you add complexity. There's a far greater chance of 0kg returned, and getting that back up to a simple mission's chances is expensive/impossible. There's a reason they didn't livestream the landing.

It seems unbelievably complicated just for a return sample. I suspect they are practicing for a real Apollo. Or maybe they wanted much more rocks than the Soviet mission and had to go full Apollo to maximize what could fit in the rocket. And perhaps I shouldn't say "Apollo", but "Saturn V" as there was a "direct ascent" plan and some work on designing Nova rockets (as well as Saturn C-8) to do that. They would have been huge and even more expensive and risky. But humans (and life support) are a fixed size: you can scale a sample return however you want. But if you want to maximize your samples while sticking to your Long March booster, then Apollo it is.

If it is anything like Bennu, you wouldn't need a nuke. Just some TNT the size of three backyard-grill propane tanks and you are set. Just make sure you do it early enough that most of the asteroid drifts out of the capture radius of Earth's gravity well: a dispersed asteroid probably will burn up in the atmosphere, but the Earth could be missing summers for years if you dumped the mass of a dwarf planet into the atmosphere.

Telecommuting. It was possible earlier, but getting proven now. Nothing is really "not being destroyed by Covid-19", but a few things are in trouble. Theaters (especially live performances, although I can't imagine that film theaters are doing any better), office buildings, support for office buildings, restaurants, schools (more the buildings, buses, and other "in person" infrastructure, not the teachers and students). One thing to note is that the logistic chain for trees is [well was in the middle ages] relatively trivial: a woodsman cuts down a tree. If you need charcoal probably someone else turns it into charcoal. Finally somebody hauls it to where it needs to be (possibly stopping by a mill to turn it to lumber). Oil and gas require extreme long term investment, and don't "shut down" easily. Oil has only limited competition, electric transportation is in its infancy and is unlikely to be effected by Covid. Natural gas has real competition (especially for high dollar peak electrical use) in solar and wind. I suspect that wind turbine production can ramp down and ramp back up again relatively easily. Solar production uses fabs not unlike (low tech) silicon chips, so they might just run continuously and stockpile the panels (or more likely demand will increase, especially if residential use increases and they keep the offices cooled anyway). In any event, any changes to the supply of oil and gas won't change at all (if Saudi is on the verge of running dry, that might be a huge political thing, but it isn't a real change in supply). The whole expensive logistic chain is what to watch.

When was the last time you saw someone take a railgun or laser into a mineshaft? We have that "sci-fi worthy" tech right now, as long as you don't care about getting it into space or cooling it in vacuum. But that simply isn't how you want to mine. Don't expect mining to change significantly without a gravity field. Unless your "mining target" is held together like Bennu , in which case you want to "break it apart" with gentle taps and scoop up each "target size" bit. And of course, the answer to your title question is "You just fly through it. Avoiding asteroids is entirely optional (although not doing so may lose a tiny percentage of spacecraft)."

Nothing I said was about asteroid mining, unless you are worried about a claim jumper blasting you with a mining laser (might make a great bit of sci-fi, along the lines of a space western). On the other hand, it may be far more efficient to simply focus solar power with a giant mylar mirror instead of building the laser. My point was that the radiators are going to be a big target. Others have pointed out just how impossible it is to focus a laser across interplanetary distances. Blackbody mirrors *are* radiators. Just perfect ones. And "perfect" materials don't seem to mix with high energy (at least things like superconductors and similar large-scale quantum effects). Note that if you had such a thing, it would also make an interstellar (maybe just for probes) drive (nearly infinite Isp).

How? Most efficient way commonly used is heating a gas to spin a turbine. That should top out near 66% efficiency or so. Regardless, your radiators will have to emit nearly all energy generated by the reactor into blackbody radiation (less the emitted laser. But that can't be a significant percentage). As the lasers get powerful, the radiators get larger. I'm sure I've quoted the calculations at you a few times. None of these address the power source you'd need, nor the efficiency of the laser. Even with fusion, you'll have such massive radiators that they would be obvious targets if you could attack them from three non-coplanar directions.

Oddly enough, the only reason the forests in Medieval England recovered enough to keep building watermills and a medieval industrial revolution going was the Black Death. Not enough demand for wood for a generation. Yew trees aren't extinct, although we must have gotten lucky as it takes hundreds of years for them to grow (they are typically grown as shrubbery. Getting to tree size takes a loooong time). The amounts of uranium needed for breeder reactors is trivial. If you are worried about running out of fuel, thorium is even less limited (although it *requires* plutonium instead of creating it. So presumably you would need a few breeder reactors to go with your thorium reactors).

While NASA does have strong ties to the military-industrial complex, it entirely exists at the will of Congress. Congress thinks it is a useful way to distribute pork. It also is like NSF (National Science Foundation) with way better PR, so expect it to continue taking a large chunk of the science budget. Remember that NASA has never built a rocket (oddball prototypes ignored). They contract various space companies to build them, often with far too much oversight and micromangement. While Spacex has a lot to do with the change (although it wasn't clear they were what they had in mind for commercial resupply originally. I'd guess Orbital (the first commercial satellite launcher), although they only joined the CRS program after one of the original awardees dropped out). The other huge reason that NASA may have to do this is ULA. With the creation of ULA, they are effectively all of "old space". If NASA wants to contract out a rocket to "old space", they no longer have contractors and subcontractors, they only have "ULA" (ok, they will have a few subcontractors, especially for engines. But the contract will basically be controlled by ULA, not NASA). Pretty sure SLS is Boeing (which owns half of ULA) not ULA itself. Boeing also isn't going anywhere (although their shareholders might not have much left) thanks to heavy-handed US government support.

Likely only a single order of magnitude, and only if COVID-19 disappears with the next few years (probably more than one order of magnitude if it disappears before you tick age 50). US - typical death due to car/truck crashes: ~30,000 per year (with an additional 5k motorcycle deaths). Deaths due to COVID-19, three times that for less than a year, and rapidly increasing. No only that, but the distribution of dying in cars is skewed between 20-40, so if you are under 50 you are far more in danger in a car, where if you are older COVID is still a threat. Don't forget that US pedestrian death is 1/6th the in-vehicle death (and probably far, far higher per mile walked than per mile driven). If you walk instead of drive, you probably haven't helped your chances at all. Make sure you have all your needs delivered to you and don't leave home. As a bonus, you won't get COVID-19 either (unless your deliveryperson is positive and not wearing a mask).

It does? Hot sauce packets are in high demand on the ISS because it is one of the few things you can still taste. I'd be surprised if balogna also was an ISS favorite. Note that this doesn't seem to be dependent on orbit, more likely how long you've been in zero-g. But in practice "tastes the same in orbit" isn't true.

You're forgetting about balancing all the phases across all the generators over the entire grid. Perhaps Germany doesn't connect large grids, but in the US [lower 48] power is distributed in only 3 grids, and one of them is mostly Texas. "Hooking up new clients" is trivial. Hooking up new generators is where the problem lies, and solar and wind power make this even more of a challenge. I wouldn't be surprised to see DC connected "AC microgrids" that are small enough that the phase issue is moot, although getting there from here would require significant engineering. First mile to last mile DC wins on phase issues. Last mile DC wins on being more compatible with power supplies (especially considering EU directives about power correction). AC was great from the start of electrification to ~2000, but isn't that great now.

Surface gravity on Uranus and Neptune are .9g and 1.2g respectively. Even though they are well over 10 times as massive as Earth.

They weren't built because they don't work. Maxwell's equations (and moreso the quantum electrodynamics that cause them) are known to be correct to something like 8 decimal places. There is no room for Tesla to be right. In general, any invention that isn't built either doesn't work or is sufficiently derivative to not be worth the name. These don't work. Delivering high power without wires is indeed possible, and that is more or less how transformers (the reason AC won 100+ years ago) work. The catch is that while electrodynamic waves lose power by r-2 (inverse square law), inductive losses lose power by r-3 (inverse cube law). Also the "breakeven point" is related to the wavelength of the frequency being transmitted. You see this a lot in wireless charging, and getting the location *exactly* right is critical in getting the thing to charge at all. The shocking thing is that Tesla not only managed to make the inductive motor, but quite a few more things to work. But I suspect that his broken understanding of electrodynamics was *just* correct enough to get the induction motor to work (while his competitors simply didn't understand induction at all). But from what I've heard of the "other things", they were more like radio control and other things that didn't rely so much on inductive effects. The last thing to take away from all the Edison-vs-Westinghouse (instead of Telsa) malarky is that AC is more or less an obsolete installed base that we are stuck with. DC transmission is more efficient (in the 21st century, not earlier), but would require massive investment to replace the grid. USB outlets are leading the way for low-voltage DC outlets, but electric cars (and any other high power HVAC or appliance) wants high voltage DC..

To train your dinosaur cavalry! If we are going back to pre-1960s understanding of Venus, you have to include the dinosaurs popularly expected. It was covered in clouds and believed to be jungle, and assumed more primitive than Earth, so they must have dinosaurs!

I have to admit that I'm a big fan of photon propulsion, largely because of effectively infinite Isp. On the other hand I'm certainly skeptical that there exists any realistic level where photon propulsion beats ion propulsion. Note that this probably doesn't include "standard" ion propulsion, but exotic cyclotron-based ion accelerators. Because blue LEDs aren't the only thing that can create momentum out of pure electricity: you can add all the momentum you want to an ion by accelerating it into relatavistic speeds. When you realize that it will be extremely important to have your heatsinks "white" (minimal blackbody radiation) on one side and "black" (maximum blackbody radiation) on the other for additional photon propulsion, you might realize just how inefficient photon emission can be. On the other hand, if your nukes are still producing power and you've long gone through both your Argon and Xenon, you might as well fire up your LEDs for all your remaining delta-v. Just don't plan on decelerating and orbiting any star system that way. I'd expect a rather weak last stage.

Anything but red. Blue was science, and I engineering was red (didn't Scotty wear red? GIS shows him in a lot of red). So blue it is!