Hannu2

Overrating depends on source. Tesla was a great inventor and his inventions are well known. But there is some cult around him and I do not think that for example these three inventions was credible. Maybe he had some hypotheses or primitive ideas around these topics but not anything which could have been developed to work. Electromagnetism is extremely well known area of physics.

Less damage to environment in case of anomaly, I think. Or it is just more fancy background in animation. That braking maneuver is crazy and impossible in real world. If they had not succeeded in another impossible task, landing and reusing first stage of orbital booster in economically feasible way, I would not believe.

I agree. Exotic physical things, like black hole mergers which release in few milliseconds orders of magnitude more energy than Sun will ever produce as gravitatonal waves, exotic phase of matter in neutron stars or strong relativistic effects near giant black holes may be more strange, but my intuition expects nothing in such extreme conditions I do not have any experience. But ice in vacuum on sun roasted Mercury is very counterintuitive thing.

As far as I know, some EU countries build but others scrap working plants. In Finland there is one from French Areva in finalizing phase now, but it was intended begin commercial production at 2009. Also costs have about tripled from contracted budget and it is not juridically clear what part goes to manufacturer and customer (I think so, am not sure). Only sunken cost fallacy and prestige of many rich industrial owners and high politicians have prevented abortion of whole project. I think last estimate when commercial production begins is 2022 and you can guess how many jokes that project has been created. https://en.wikipedia.org/wiki/Olkiluoto_Nuclear_Power_Plant#Unit_3 There is also another project with Russian company Rosatom, but I do not know what is the status now. It is in very beginning and has not yet final permission from government. It has been mainly out of publicity in last years and it may be that failed Olkiluoto project has scared owners. Also price of renewable energy has decreased significantly during last decade and there may be also some political issues with Russians now. https://en.wikipedia.org/wiki/Hanhikivi_Nuclear_Power_Plant

We have also one project in Finland, more than decade late and exceeded a budget by several billions of €. Olkiluoto 3. Now it is in finalizing phase. But most of that is because bureaucracy level has been set to far beyond insanity. Nothing is enough to prove safety. If there were reasonable laws, nuclear plant would cost few billions and be economically profitable option. Small passively safe units, which are under development now, would be even (much) cheaper and safer. I think conversion from heat to electricity is not the hardest thing in fusion powerplant. Fusion rocket engine have all bad problems how to ignite fusion and release actual energy. Plasma must be confined and heated to absurd temperature to get any energy and there is no known feasible ways to do it, except some very premature lab tests. I do not expect to see fusion powered spacecraft in my lifetime (statistically about 40 years left). I am also quite sure that fusion will suffer also the most of political problems fission has. It is nuclear reaction after all and produce neutron radiation (which can be used to evil military purposes) and radioactive waste. Environmental activists accept never it and keep propaganda against it if commercial project sometimes begin.

It is a good question. I think main reason why fusion is always ready after 50 years is that it is solution to a problem which has not been invented yet. Toroidal fusion powerplants will be extremely expensive and probably can never pay initial investment back. Fusion was promising during energy crisis when predicitons of energy costs was exponential, but now there are much more known energy resources and also renewable energy begin to be abundant and competitive with fossil energy. If there was a real economic need for fusion power in foreseeable future, large energy companies would invest hundreds of billions in development and we would get commercial plants in a decade or two. But in real life there is not any need and it is developed by small research funding of states. I predict there will never be commercial large tokamak plants but there may be some special uses, like research reactors. It is not credible that they will be developed for spacecrafts in foreseeable future. Space budgets are so small. If there will be some significant business, like mining and refining of metals, fission reactors are much cheaper and faster solution. Next generations will probably get rid of hysterical nuclear fear caused by cold war propaganda and development of fission technology will be allowed again. Unexpected breakthrough of another smaller and simpler fusion technology may lead to different development, of course. But I do not know how credible those ideas under investigation really are.

Is there some technical reasons why it is impractical to make maneuvers, totally less than 1 m/s based on my understanding, and return to investigate Bennu from orbit? Or is it so much safer to wait time for return maneuver by coasting far from asteroid that it is better choice? Cost savings sound quite strange reason if there is a scientific probe with ten number pricetag near the interesting target.

Did you already leave from Bennu permanently?

Energy of heating is much higher than any reasonable thermal capacity. At least in atmospheric entry. Heat must be radiated out or absorbed in some kind of ablative or vaporizing system. Or what if complex sled and expensive and potentially very unsafe railing and suspension systems was replaced with a freely flying rocket stage which would kick SSTO above thick atmosphere and give some initial velocity. That kicker stage could left some fuel and return to launch site. Or maybe even land to a special ship on ocean and save some DV.

You do not need money but just some time to learn basics of physics and see that you can not buy such magnets with any amount of money. No one knows how to do such magnets so that they can be fitted in spaceship. Any known material or any imaginable combinations of known elements (their bonding follow certain natural laws and it can be predicted that order of magnitude improvements in material properties will not happen) can not be used. If you check those superconducting behemoth monsters used for example in particle accelerators, it may be hard to imagine such as part of spacecraft. And their field may not be nearly enough. As far as I know needed field strength is enormous.

Size is beautiful, of course. Saturn 5 is my all time favorite, even last unit flew couple of years before I born. It was just so big and crazy thing built in hurry with unrealistic budget. Much like Kerbal contraptions Soviet N1 must have been also nice rocket for same reasons than Saturn 5. It is sad that it had so bad luck. I hope that Starship will join to that list after first attempt to orbital mission, but it lack some steampunk like nostalgia even it will be larger and much more sophisticated. Saturn 5 and N1 are like very old diesel locomotives (which I like even more than steam locos) and Starship is modern electric locomotive, which has all technical and economic parameters much better, but just lacks something aesthetic (like sound of 180 liter V16 engine).

In Finland trend has developed from rented modems (you paid certain amount monthly) to modems you got from provider when you made a contract, but was your property to whatever modems you buy yourself. I have always got a new modem, which has been included in monthly costs. But at that time it was obligatory to make 2 years contract and modem's retail price was less than 10 % of total payment . Now I think there is no minimum time in all contracts and I do not know if they give "free" modems anymore. In any case if my modem is broken I have to buy a new from shop and install it myself. I think that moving responsibility of support and broken things to customer has been the reason for the trend (in addition to decrease of prices for modems and connections, of course).

It is very hard to see that any radio bandwidth would be enough to handle data traffic of large cities. I think cities must rely on optical fibers in foreseeable future.

In urban area 99$/month is ridiculous price but in Finland we have large areas where no one offers internet at this speed level. USA is also large country with large rural areas probably without high speed internet providers. If I remember correctly Starlink is intended for rural areas where is no other options at this speed.

As mentioned answer depends on many things, like size, propulsion system and energy consumption of craft. But probably the craft would stay undetected until it is very close especially if it were made to be stealth. Which is probably not huge cost at interstellar tech level. Even huge (radius of tens of kilometers) craft could mimic natural interstellar asteroid, like Oumuamua, until Sun orbit insertion burn, if its TWR is decent. Then it were probably few weeks away from Earth and there would not be practically any possibilities to countermeasures.

It is realistic if they will build it commercially. Probably almost anything can work technically but if they do not give significant benefits, they fail commercially and be never used. I think piloting is not a problem nowadays. It will have computer assisted fly by wire system in any case. Computers can fly unstable planes which are impossible for human pilots. If it can be developed and produced at reasonable costs, save significant amount of energy (or be otherwise environmentally friendly)and be safe to travel it will probably come in production. It may take couple of decades because aviation officials are so extremely conservative but at the end money talks. But I will say it realistic after all this have realized.

This is true. If there is a natural law which set maximum speed of information it makes impossible to have perfectly rigid material in such world. Yes, you get pushing and twisting signals at different times. They are called longitudinal and transversal waves in material physics and they have generally different speeds.

As far as I know, rough means high vibrations and not high time average of acceleration. Combustion process is very turbulent and thrust magnitude and direction varies significantly in sub second time scale. 9 engines in first stage partly cancel out their vibrations (and give more complex modes). I think there is not much more to do in addition to what has been already done. Lower thrust means lower vibrations, but have other problems. More smaller engines would also do the trick but increase complexity and costs. It is better to build systems so that they can stand vibrations. Astronauts are tough and are able to stand rough ride.

Is there enough capacity to store enough information known lifeforms need and communicate it between parts of the system in neutron liquid? Is there usable energy source and sink and ways to control energy flow? I understand the idea of philosophical thinking that everything is possible which is not proven to be impossible, but it does not lead to anything interesting. It is also possible that Walt Disney's cartoon world is real, city of Duckburg is somewhere in North American continent and Gyro Gearloose have made some strange mind disturbing device which prevents humans to detect any creatures or other objects of that story. It must be considered possibly true statement according to your philosophy, because nothing we can observe can ever prove it false. In science every statement must be able if be falsified based on observations to avoid such ridiculous mess of all possible fictive stories. Neutronium life is exactly like my example. We do not have theoretical base to predict such phenomena or observations which would tell something about such life. Anyone can say anything and think he is right because no-one can falsify his statement.

What do you mean with impossible? Do you have a consistent theory of quantum chromodynamics which predict chemistry like behavior in neutronium matter under conditions in typical neutron star? Or what do you based on statement that such life may be possible? As far as I know neutronium is some kind of liquid, maybe superfluid, and does not form any complex structures. There is absolutely no known reasons to expect any reactions like lifeforms. It is purely science fiction. However, it would not help Earth's life. Current life can not be evolutive step towards neutronium life, which works with completely different physical phenomena. It should begin from scratch. And it can never happen in our solar system, because the Sun is far too light star to generate a neutron star remnant.

You have not seen exthermophiles without very complex bonds between carbon atoms or other atoms. In DNA, in proteins etc. They are possible up to about 100 C and can occur in very high external pressure, but such bonds are not stable at star's atmosphere. Or you can not find any alive things from magma in Earth, because chemistry in which all life is based do not work at around 1000 C. There should be new natural laws unknown to us to make life in stars possible. New interactions and new particles which could produce complex structures. Changes in Sun are so slow that whole Earth is sterilized millions of years before visible surface hits to Earth. It will probably melt the whole crust to global magma ocean.

Have all of them been full rocket engines or some test objects with limited parts? If they have blown up more than 30 units so far in different experiments Raptor test engineer must be a dream job.

Self replication is obvious solution to problem of huge area under exploration. It makes exponential growth of exploring ability possible. It makes possible to chart every planet on every star in whole galaxy in geologically or biologically relatively short period. Practical solution would be some kind of robot colony which send smaller mining probes to asteroids and assemble robot factories on suitable orbits. Every solar system has materials and energy needed. All humans's machines are made from few tens of elements by using electric and thermal energy. What is the material you think is so special in our solar system? As far as I know everyone of them (at least which are used in industry) have been detected from space and there is also theoretical base why we can expect to find them everywhere. It is completely impossible with current or foreseeable technology. But there is no known restrictions from known natural laws. It is very much like interstellar traveling, which is many orders of magnitude away but no clear impossibilities are known. I am quite sure that we can build automated self replicating process and test it in asteroid belt before we can transport such system to nearby star system. Probably interstellar crafts will need some kind of intelligent and self repairing robot swarm to maintain them during very long trips. It is easier solution to believe than exotic energy shields against damage or near light speed propulsion at least for me.

I have always Mandelbrot set. My avatar is central part of my flag.

I have heard that you can build own spaceships in stock game too. It is certainly boring to fly spaceships some other person has planned but real fun is to build your own.