Hannu2

You are right at individual level. In combat between modern infantry unit and ancient archery army few modern soldiers would probably die. But total result would be certain win for modern army. At system level idea of defense is not to make conquering of the area impossible but just too expensive. Even small country can survive near superpower, if it has credible defense. It is enough that leaders of superpower think that place is too expensive country to attack and they choose less developed neighbor instead. War is business for leaders. They may conquer resources or need distraction for their games in domestic politics. In both cases they count benefits and costs and make decision. Crazy dictators who attack for ideological reasons are very rare in modern world and usually very soon ex dictators. It is very difficult to predict what interstellar aliens benefit it they attack to humans and what they count as costs. It is true, that if their level was not technomagic, humans could probably destroy some if their units and kill some alien individuals if they had not fully robotized army. But it is also difficult to believe that any aliens who attack against foreign civilizations for whatever reason could not stand any losses or estimate strength of targets before attack. If they have decided to attack they will do it. In any case interstellar operations need so high tech level compared to what we have that I can not believe that any defenses we are able to make would cause aliens to think that Earth is too expensive place to attack. We would be a wasp nest which is removed from garage. Pest controller could get itchy sting if he is careless or arrogant, but wasp's probability to continue their living is zero.

I think that living on planets may be obsolete if 1t antimatter bombs are military weapons. Couple of such bombs would change planet's atmosphere unusable and spread radioactivity everywhere on surface. It is probably better to distribute people to many huge stations around solar system. Stations are much more difficult to hit and easier to defend. I think also so. Beams are not credible technomagic weapons, if we do not assume completely new natural laws. Missiles may be able to imitate asteroids, but probably very sophisticated detectors can detect and destroy them before they are in damaging range. Actually I would bet that there are completely new methods for warfare. Cyber attack to enemy stations living support system or using nanobots or some new exotic technology may be more practical way to destroy enemy units than high energy or brute force. Or maybe warfare will be just too disadvantageous to all forces. Most wars are competition for limited resources but there are practically infinite resources in space.

Even 10000 km or 100000 km are short distances in interplanetary space. You can also change numbers to whatever you want. It is not obvious that antimatter driven space destroyer from year 5350 is even on the same order of magnitude in size that largest current marine warcrafts. It is also impossible to say much about combat tactics of such fleet. It depends also on defenses. In my opinion it is not good fiction to assume antimatter stuff but think that such missiles are impossible to detect. If it will be possible to build such missiles, which can close to destroy range without noticed, large ships and command centers may be obsolete. There can be large number of missiles hiding in Kuiper and asteroid belt and waiting command to hit somewhere. At least fleets with small distances will be obsolete.

As I showed, energy needed to cause damage is enormous. 1 t of antimatter, which needs technomagic level technology and we can not even know is it ever practically possible, can not cause damage from 500 km away, which is very short distance in space. Of course you could attack against ISS with large antimatter or even nuclear bombs, if you were a commander of supercivilization's space force, but if you assume about same level of defensive technology, practically possible radiation pulses are easy to absorb under credible conditions (for example separation of thousands of kilometers between space fighters).

Thickness of significant atmosphere is at most few tens of kilometers. Approximations of aerial explosion are totally useless in space and also in atmosphere if bomb is big enough. If I remember correctly those approximations failed already in 50 Mt tsar bomba explosion, because most of energy "leaked" straight to space through thin atmosphere. It is extremely difficult to make effective area destruction effects in space. It would need neutron stars or other exotic and practically impossible power sources.

You seem to overestimate power of antimatter bomb. 1 t of antimatter annihilated with 1 t of matter produce 1.8E20 J. If it is distributed evenly on sphere with radius of 500 km it gives 58 MJ/m^2. Heating 20 C water to 100 C and evaporating it consumes 2.6 MJ/kg. Water shield of 22 kg/m^2, or 22 mm thick layer, could absorb 58 MJ/m^2. Practically absorption coefficient of gamma radiation is low and need thickness of meters, but if you think technological level able to refine and handle tons of antimatter it is not hard to believe that they are able to take material from asteroids to build shields needed to protect themselves. Thick armor would not overheat and be expendable. If you use large antimatter driven spaceships you probably intend to travel at least interplanetary distances. 2000 km is pretty much nothing in such scale. For example, a sphere with radius of 400000 km (Moon distance) can contain about 64 million spaceships with distance of 2000 km. Antimatter bomb could be usable to destroy some kind of single important local base or station, but you would need one bomb per ship. Or practically much more, if ships had protection measures, which they would certainly have if there were risk to be attacked.

They have also far too high thrust to be safe on docking maneuvers. They use centimeters per second instead of meters per second in KSP and use several hours to make same operations than experienced player makes in 2 minutes in KSP. Lack of F9 button and 10 digits in pricetag make some people careful.

Time period when "profits" are calculated only in money is relatively short. I think that it is just adapting to industrialization and will probably go over over centuries. Most of humankind history profits have included much more than just simple money. Probably any of historical monuments have not been profitable in modern way of calculate. But superpowers states and their leaders have chosen to do so instead of just increasing soldier and weapon production which have probably been more profitable. In past centuries profit included religious and ideological things etc. and in coming centuries driving ideology may be for example monumental scientific projects, like colonizing of Mars. At least I hope so. And of course personal objectives of mighty individuals have been and will be very important. Exactly. Every breath of air needs fans, filters, carbon dioxide scrubbers, control systems, power generation etc. Mars will not be a nice place to go live easy life with low budget. As you said, it will not be profitable business. If Mars is colonized reasoning is ideological exactly like most of current science or Apollo project was. It it was profitable in terms of modern business, first colonies would have been established already by biggest companies (owners of them). But because it is ideological it has to wait until technological level and economic production will increase so that willing small part of people can begin it. Much like Apollo had to wait that missile technology produced working rockets and basic space tech after which developing of manned operations or moon operations came economically possible propaganda tricks in cold war. But without military applications I am not sure if orbital rocket had been launched yet. Who had paid massive development decades without any profit before first communication satellites? On Earth decision of a reactor is very political and number of reactors is important thing. It favors technically very non-optimal huge reactors which need sea or big river to cool and are passively non-safe. Large reactor need running active cooling weeks or months after shutdown. We have sad example in my country, new very large reactor have delayed about a decade and been many times more expensive than estimated. But there is so much authority and money in project that it can not be canceled. But they got permission to build exactly one reactor. If they had built two with the same total power plant had been run a decade and produced billions to owners. Martian reactors will be much smaller passively safe units. Cooling of 100 MW is much more manageable than cooling of 1 GW. Small reactors have been planned on Earth too, for example: https://en.wikipedia.org/wiki/Pebble-bed_reactor There is nitrogen in Martian atmosphere and hydrogen in ground (as water). They may be combined to ammonia and further processed to nitrates with similar chemical processes than is used in fertilizer production on Earth. Locusts are like many dangerous things in industrial society, like toxic chemicals or uranium 235. They are good in controlled processes they are intended to work but bad if too large amounts are released to environment. Animal production of Earth is not good example. Many people have attitude against insects and vertebrates is cheap to grow. My information is from local guy who try to get crickets as profitable business. So I do not have references and this is not scientifically valid. He have container like units. They are easy to replicate if needed and production would be possible to scale industrial size if there were markets. Old ranch could produce more tonnes of crickets than beef with minor modifications on buildings. If I remember correctly he said that crickets produce about 5 times more proteins than cows from same amount of vegetable food. Consumption per body mass depends on activity. Invertebrates do not need to keep body temperature and crickets do not need to use energy to search food or avoid predators. Crickets grow in optimal conditions in less than 2 months which is much less than growth of cow. This depends only on attitudes and economy. There is no technical limitations. Crickets can not compete economically with vertebrates under current regulations. Traditional agriculture including animal production is heavily supported in most countries. There are big economical support, regulations allow significant harm to environment and ethical regulations are sad jokes. But regulations are expected to be tightened which increases vertebrate meat price much more than insect meat. I thought artificial manipulations. They affect immediately (when individual grows, but do not need geological periods like natural evolution). All modifications must be tested. It is impossible to change whole population's genome. All manipulations affect only to one individual and his offsprings. Of course there is clear ethical problems and I do not see good way to overcome them. My guess is that there will be collapsed states and dictators very long time and they drive biological development regardless ethical considerations. Dictators will fall but rest of the world begin to use scientific data. Not nice way to proceed, but history is not nice and it would be credulous to expect that future will be. There will be failures like in all technical development. Therefore I mentioned huge ethical problems. But when ethical things have limited human stupidity over long periods? Your critics is what prevents to proceed now in our relatively civilized states, but not based on any natural laws or other impossible things. They are just current human decisions. Civilization is split in any case when it begins to spread to space. Or one or some factions of already splitted civilization, which seems more realistic situation. Exactly like it was split in history when people moved to other continents to make colonies. They developed, began to compete with founders, declared independent, fought for independence etc. It will not be anything new or prevent development. At least I do not see reason why. Probably very advanced technical civilizations are less inclined to competition at all levels. In long run most productive civilization wins and competition is not the most productive way to make things. It leads to parallel work, intentional harming etc. well known issues. I do not see reason why current state of social development would be absolute maximum for our species. Societies have developed during millennia and will develop in future too. Development is slower than scientific or technological development, but as sure in long run.

Mars colonies will be dependent of Earth support centuries from beginning. But probably basic agriculture is one of the first things to do independent. High tech stuff is much more demanding without proper infrastructure. There will not be open fields like on Earth, but most plants can be grown in hydroponic systems in large greenhouses. Nuclear energy is unlimited without strict environmental and national security limitations and give warm and light if needed more than Sun can deliver. If some elements are rare (is there phosphates available on Mars?) they must be recycled very carefully. And most other vegetables. Also potatoes grow very well in hydroponics. It is energy and vitamins for humans. For example insect farms can produce proteins in much less room, energy and raw material than usual domestic animals. If some specific nutrition stuff is not available, it is easy to produce chemically. Mars is certainly not right place for those who appreciate natural lifestyle without artificial food additives (and whole food, water, air, everything). Mars will be high tech civilization from very beginning without option for primitive lifestyles. It is primitive intelligence. Real intelligence changes body, if it is impossible or impractical to change environment (like terraforming of planets certainly is). Earth have examples of adaptations to very strange conditions. It must just be learned to do.

Because Mars is there. Expansion is nature of species. It does not have to be advantageous to individuals who make them, except indirectly through good feeling to do something special. Scientific curiosity, technical development, need to break barriers, display of power etc. will be driving force. Technically it would be better to make huge space stations. Probably both will be done in distant future. Production and environmental protection and living room may be more important reason for space stations. It is as difficult to see advantages in industry compared to asteroids and space stations. Asteroids have much higher concentration of precious elements and no problems of gravity, weather, seasonal and/or diurnal cycles, gravity well etc. I think that sentimental humans can colonize Mars and other larger bodies, because they are there and it can be done, but reasonable industry goes to asteroids and stations.

Why not? Most of Earth cities seems quite nasty places to live for me and my house in middle of nature in subarctic climate would be very nasty for most of people in World. Such things depends on culture and changes quite rapidly. Probably virtual reality equipment will help such problems in quite near future. Terraforming of planets is technomagic and I believe it will be forever. I think it will be far more easy and far more economical to manipulate humans genetically to adapt in microgravity than terraform planets suitable for current humans. Maybe majority of humans live in massive space stations after couple of thousands of years and planets are for some extremists, scientists or fundamental religious people. Then there will not be any reason to terraform planets even it will be possible at some day. Planets and their life and distinct geological phenomena may be protected instead of colonized. I think this is very bad problem in first colonies. It makes also generation ships incredible in my opinion. There will always be problems with power and abuse and it is impossible to make colony immune to sabotage if someone is willing to die for revenge. And we know that there will always be such people. But on the other hand, it has been problem always and there is change to survive. We have to just change our attitude from modern nitpicking to risk handling of exploration era. We begin ten colonies. When all of them fail we begin hundred new. Eventually some of them grow over critical phase and will be immune to human behavior. In very distant future it is probably possible to manipulate also behavior intentionally and create a successor species suitable for cosmic civilization. I think ability to make intentional genetic manipulations will be as important steps in history of life than multicellular organisms, aerobic metabolism or transfer from sea to dry land. Of course not in our lifetimes or in immediately foreseeable future but in short time compared to history of human as species and several orders of magnitude shorter time than history of life. It may be reason to branch humans from biologic kingom Animalia to some new kingdom which controls reproduction and evolution intentionally with high technology instead of natural selection and other biological evolution mechanisms.

That may be interested situation, when 100 begin vomiting without experience how to use vomit bag in zero-g. I hope they take corrosive stomach acids into account when choose stainless steel type (fortunately many of them can handle mild acids pretty well). I would not like to be there (actually I would very probably vomit, my stomach is quite sensitive for even moderate g-forces in amusement parks).

I hope they make it possible to model solar system properly by allowing axial tilting of bodies. It would be interesting mod also in stock size solar system to add more inclination and give axial tilts for planets. I usually triple Outer Planet mod's inclinations to get more interesting trajectories.

Exactly. I love realism in games, often over entertainment, but I abandoned real solar system after first Moon trip because maneuvers were too long. Ascent took 10 minutes and was guessing how to steer rocket. In KSP you can fly however you want and get to orbit, but real ascent is more complicated and depends on TWR of stages. Typically first stage or solid boosters have high TWR and they throw ship to high arc. Upper stage has much lower TWR than typical KSP rockets (about 0.5) and need time to accelerate to orbital speed before falling down. For example Mechjeb's ascent autopilot can not handle it properly. I would like very much real solar system if there were proper tools to plan and execute maneuvers with high enough time acceleration. But without proper tools it is too tedious. There is also problems with limited accuracy of doubles (internal floating point numbers). If you model Solar system up to Pluto resolution of place is on the order of millimeters. It is significant problem for example if you try to dock with very slow speed. There is ways to overcome it by math (which is certainly used in KSP if it still uses 32 bit float numbers) but it takes time to program and time to execute code and add possibility of errors.

I agree. Mechjeb functionality and porkchop plotting (which works also with inclined coast orbits) should be part of KSP. At least I do not see any fun or educational value to be forced to make calculations separately ans then execute tedious operations by hand using eyeball measurements instead of exact data. With Mechjeb I can manage more interesting missions in my limited freetime instead of use my time for tedious manual maneuvers.

It is very possible. SpaceX's publicity makes fair estimation difficult compared to companies which makes development hidden. It is difficult to know for example how Blue Origin proceeds, probably they announce ready New Glenn few months before launch. And of course traditional operators have economically huge programs too, but they have too many rent seekers and results are very small compared to costs. OK, thanks for the information.

Is there really significant difference with rocket fuel tanks? It is certainly beneficial in this kind of tests, but if a big hole appears during launch pad operations violent fire which bursts the whole rocket may be hard to avoid. And during ascent such a leak means certainly mission failure and immediate RUD. Maybe they can get some tenths of seconds for aborting capsule but not much more.

I am quite sure that in both coasts of Atlantic important companies will be subsidized long time. Europeans want to have "own" rocket and Americans want to keep traditional military companies running. Probably they lose commercial launches but states continue to buy launches and fund companies. I do not also believe that billionaires use their own "unlimited" money to develop space tech for science and humankind. They think always profits, they would not be billionaires otherwise. I believe that also Musk have thought billions from global satellite net when he has given PR talks about colonizing Mars or other bulls... er.. aspirational visions. Strange people, they think money even they have found a bit which gives "unlimited money" from save file. I would certainly think only consuming of money, for example in crazy science projects. But that's why I am middle class nobody and they are billionaires.

SpaceX's PR is based on publicity. I am sure that other companies make tests too, and fail sometimes, but behind fences without cameras. SpaceX's development pace is also probably more than all other combined in the world. Their advances in last decade are exceptional. They began from nothing and have taken largest share of world's satellite launches, their reusable rocket is overwhelmingly more advanced and economical than any other manufacturer's products and next they will begin crew transports for NASA. If they get Starship operational for heavy satellite launches in next few years they even increase their distance to others. I hope that Blue Origin can challenge them very soon, because monopoly situation is never good in long run. I do not believe that traditional big companies in USA or Europe can do it without massive political subsidizing.

Basically train driver should know, but this guy has probably have some kind of psychosis and his sense of reality (this has probably some other english word) has been decreased. Train engineer is historical name for profession. In previous decades steam and diesel locomotives needed much more service and repairs and driver had to fix damaged locomotives in line or temporary conditions to get them to workshop. They had much more responsibility in technical thing and had to know how locomotive works and how o find and fix problems or report them to workshop if needed. Modern locomotives are fully computerized with self diagnostic tools and very specialized tech which can not be repaired in railyard sidetrack or even railway company's workshops. They do not need much daily service and are extremely reliable compared to 50 years old locos. Also most of service is changing modules and send them to manufacturer's workshop. Engineering skills are not needed anymore for drivers as much and also in workshops. I know that in my country railway company have decreased demands in engineering background, part of engineering in driver education and also shut down many repair workshops during last few decades. On the other hand safety rules and equipment have become much more complex and need bigger part in education and practical work.

As you see, chassis of locomotive has kept is shape. Nothing have compressed driver. Locomotive is very massive and deceleration is quite slow, if it does not hit to hard object, like another locomotive or hard buildings. Locomotive may have slided hundreds of meters before stopping if is has really ran at full speed, which is probably around 140 km/h with such heavy diesel freight locomotive. But I am quite sure, that safety system has allowed much lower speed, because locomotive body seems to be quite undamaged. It is strange that it has allowed loco to run pass red signals without automated emergency braking. I do not know what kind of safety system is used in USA, but if I remember correctly disabling of safety system (which may be done in special situations with special permission of traffic controllers, like carefully pushing damaged and stopped train to next station or passing track construction area without fully working safety system) limits top speed to 50 km/h in Finnish system. And as far as I know, driver has no simple way to override that.

This kind on information about materials are very interesting. Especially this, because at least my default thought is that spacecrafts are always made from super expensive alloys of exotic elements but 304L is very basic stainless steel which I have bought from my hardware shop at cost about 10 €/kg for hobby projects and even I can weld and machine it (it is actually 304, but as far as I know 304 fulfills usually 304L requirements too, only difference is carbon concentration limits). Actually it is the most fun and forgiving material to weld amateur weldings (professional special welding, like pressure vessels or aerospace applications, is another story and I am wrong person to write about it) but quite nasty stuff to machine with hobby level tools.

When they began to plan JWST, they had no idea that such rockets would be available in next decades. It would have been impossible with NASA way, from which SLS is perfect example. It is typical that flagship probes take more than a decade to build and they are obsolete from hindsight perspective when they are finally launched.

Those Mars schedules are extremely overoptimistic. Or given in Musk -time, which is about an order of magnitude slower than SI units. In real world it would be good work if they can launch first commercial satellites to orbit in 2022. To be honest there is quite huge step from simple hoppers to orbital class vehicle and it seems that development does not go as intended. If they have an anomaly with later orbital capable vehicle it takes easily more than half year to just make paperworks with authorities before they can continue experiments. After that it takes several years to get man rating to LEO. And probably more to get license to land crew on Moon.

If I remember correctly, there was a delay in some Shuttle launch because there was bad weather on some airport intended to use in some abort situation. But it was more than a decade ago and I am not sure. Did they have suitable airbases for abort in Africa?