magnemoe

Agree, extended family groups was the standard social unit until 10 K years ago. Yes it was larger units but they was mostly to meet others, trade and solve conflicts. Slavery was mostly ancient, it died out in most of the world, yes you had forced labor, but much softer. Slavery got an upswing after colonization of America as it was an labor shortage. Now part of the reason slavery died out in Europe and probably other places is that slaves has an added cost, you have to hire guards to keep them in line or treat them well enough that they stay. If you can hire people cheap enough why use slaves, if you have enough hungry unemployed they are likely cheaper. Back in the bronze age wage labor was not really invented yet, you was part of the family or you was paid for an task like gig or day work, or you was an slave. Rome and some other place probably took so many slaves because their wars they became an slave economy. Taking Jerusalem after the Jew revolt paid for Colosseum. Imagine wars being profitable, expensive weapon system has multiple benefits

Yes getting into orbit orbit after flying in the atmosphere of Saturn. An nuclear ramjet switching to liquid hydrogen then atmosphere get too thin even then hypersonic is the closest tech option.

But movies has an timeline of 2 hours, so story need to be short and therefor simple. Having two grey factions is great in and multi seasons tv series or an +100 hour video game, not in an 2 hour movie. Heard lot of calls for simpler enemies. Now if you can do this if the villain motive understandable like the ship AI in Wall-E. And it was correct, returning to earth would be an hundreds of year process, humans could not survive on earth yet. The villain part was trying to keep status quo at all cost.

Yes, but you need much more oxidizer than fuel even if burning fuel rich.

Yes nuclear also has practically unlimited range. Radiation shielding is an issue, would work better on an long plane. You could simply use electricity to make heat, way less efficient than propellers, however electrical propellers might be more effective than an an turboprop if you have to bring the oxidizer because the very high efficiency of electrical engines offset lots of the low power density of batteries. Electric cars is an bad comparison, they work well as your rarely use more than an faction of the engines power.

Area is the area of the ducted fan in m^2. who is pi*r^2 =0,0177 m^2 with an 15 cm fan but plugging that into the formula gives 0,000389 tip speed should be 0.6^2 who give an even lower value 0,000234 so something is wrong here

This, and it would probably work much better with good fusion. Or if you don't care about radiation as you are on Venus or Jupiter you skip the heat exchanger, look up project Pluto, nuclear ramjet

Like the V-22 so nothing new I say, why not go for an tail sitter on a drone, fixed wings for cruise performance, propellers above and below wings for takeoff and landing. Benefit of the V-22 is that is can take off with far more than its VTOL landing load from an air strip. but its burned so much fuel it can land unload and fly back.

Yes, rocket engines are hungry. It burns even more LOX. This is the main problem with cross-feed and drop tanks, you have an flow usually only seen in hydro plants. Yes some large water handling systems might handle many ton's second but here pressure is low and bubbles and cavitation is not an issue.

Jet engines bleed air trough the turbine blades to cool them, my idea was to do this with hydrogen. And yes early jet engines just lasted some hours And jet engines are more complex in many ways as you are burning air not pure oxygen, air pressure variations and as you say environmental factors including noise, also orders of magnitude longer flight times. I'm sure its lots of engines on long distance flight who has burned for longer in an single flight than shuttle or falcon 9 engines has burned totally but jet engine then does this the next day

The rotating lower jaw one was amphibious and used by intelligent dinosaur to cut down trees and make planks. Flintstone was pretty accurate outside the humans and the pointless cars. They had everything from fast cabs to +100 ton trains pulled by the huge dinosaurs. They was expanding out of current day Mexico. They did not have an space program

Second one is just pretending, but this is nor folding, just flexible. Once we stole an plastic banner and carried on our head because it was raining, we was obviously drunk, it was flexible but not folding like an umbrella.

LEO and later the moon works better, shorter travel time and an luxury hotel both paces would be viable down the line. Multi year trips then you can not talk normally on the phone has issues if you need to be connected. Yes some people will pay for it but it would not bankroll the operation like orbital and moon hotels. You then attach the research to the hotels as its cheaper anyway, And you get to run on water on a pool on the moon.

Yes jet engines run lean on 20% oxygen in the atmosphere. Rocket engines uses lox and fuel, mixed together, great care has to be taken to not melt the chamber. Putting an turbine in there is idiotic hard. All turbo pumps is inefficient by design as you can not run them like rocket engines as you melt the turbine and this is just to power the pumps. Now you could have the inefficient burned mix feed into the engine chamber, eliminating the loss if you can handle the higher pressure. Obviously if you could run an turbo pump as an rocket engine you could just use it as an smaller rocket engine at the side who would be much easier but still very hard as none has done it. Now you might pull this off on an smaller hydrolox turbo pump, burn it oxygen rich, use LH2 to cool the turbine by pumping it trough blades for cooling, then an second chamber before the nozzle and exhaust is fuel rich. You can use this for roll control and does not get usual open cycle losses even if open cycle. Its not something SpaceX would make.

This, it's probably easier to see on an rapid rotating airless body. Now one weird effect in KSP is that if you shoot an rocket straight up say 10 km it will come down west of launch point. This is probably simply that Up in orbital view counter the rotation.