RuBisCO

I was thinking nuclear fuel pellets, grains even, sand size, in a rotary nuclear rocket engine, held in place by centrifugal force alone (or perhaps sintering when cooled to low temperatures when the engine is off):

No a reactor can be designed to minimize or prevent superhot corrosive propellant from contact with it, remember existing H2+O2 chemical engines are also shooting out superheated steam and not disintegrating. An H2/O2 is probably a safer bet technologically, also it solve the reaction control problem, for to have nuclear reaction control you would need a axillary nuclear engine running at lower temperatures to push steam down pipes and out of nozzles for 150~200 Isp out RCS. Also H2/O2 engines are likely more easily throttleable then nuclear. Of course Mars makes CH4/O2 viable which is easier to store and work with then H2. Hydrogen from ISRU would most likely mean you are stuck with O2 as waste product (if manufacture from water) for ever 1 ton of hydrogen one gets 8 tons of oxygen waste! Per ton of water required a nuclear water engine of 450 ISP outperforms as nuclear hydrogen of 1000 ISP out of 15 km/s of delta-v, because you have to go though 8 times as much water to fuel up the nuclear hydrogen. There is another option though which is to use oxygen in a ion engine and hydrogen for landing purposes.

In theory a rotory bed reactor would minimize how many parts are touching the steam and allow for superheating in the void above the fuel elements as well as film cooling along the exit throat and return to pump throat. At 3500K most of the water is splitting back and forth from O and H radicals and back so yes incredible corrosive.

Yeah I tried that, did nothing visible, does not turn the shadows off. The problem I trying to solve is that on Eve (with Eve and on the planet Eve) the shadows of the clouds build up over light from the craft, such that even if you turn the headlights on those are muffled by the shadows, weirdly the flag decal is not. Ideally when under clouds there would be no more shadows from the sun, and it would be general defuse lighting.

It may be worth the cost in that it can use water, radically reducing the processing needs of ISRU propulsion manufacturing: no need to crack water into hydrogen and oxygen, no cryogenic and deep cryogenic coolers and storage. Heck on Mars CO2 could simply be compressed and used directly although an Isp above 250 would be unlikely, that and carbon migration and coking might be a problem (at insane temperatures CO2 breaks down to C and O2, and thus carbon soot could build up in the engine as well as migrate through the hot metal changing its physical properties for the worse) but propellant straight from the air is a sweet offer. Machines have less radiation concerns, though putting the nuclear engines far behind with a shade shield would provide good protection for crew, except when landing as radiation will reflect off the ground. Certainly to test nuclear thermal in space it should be on unmanned ships at first. Yes I don't see reprocessing as happening for this, they will be used until they are used up and then buried somewhere, more fissile fuel or just fresh engines would be brought up from earth, the argument could be made to the public that each one required the cannibalizations of nuclear bombs. I have a scene play out in my head of thousands of years in the future people on terraformed Mars who have forgotten the past come upon an mountain surrounding by giant titanium pillars with warnings written all over and images of skeletons and trifoils on them, and they have to figure out what it means "Perhaps the ancient ones are warning us of something terrible being buried here?" It should be noted that nuclear reactors in general have a lot of void fuel, fuel needed to maintain criticality, that is once the reactor uses ~10% of its fuel it can't hold criticality anymore, so the other ~90% goes to waste. So yes reprocessing would be good in recycling engines, but the infrastructure required is rather large, it is not a easy task as the fission products come in just about every element. I would hope for fusion "torch" ships running of He3 or B11+H1 would do most of the work of orbital running and nuclear thermal would be more limited to landing and taking off from moons and Mars. Unmanned Solar sails would be best for asteroid mining as they can be manufactured from the asteroids out of cheap metals (magnesium and aluminum) that may be by-products of refining precious metals.

Lets say we have nuclear rocket engine of 100 kN of thrust, at 480 s of Isp it would go through 21.2 kg of water per second. Assuming ~3500 tons of water efficiency previously calculated, it would take 45.8 hours to go through all that water for 1 kg of plutonium. Lets assume a 4000 tons wet weight, thus 500 ton dry weight so nearly 10 km/s of change in velocity, but at a pitiful average of 0.06 m/s^2 acceleration. Now is two days of continuous thrust a torchship, no, nor is going through that much propellant. The advantage though is that said nuclear rocket engine could go through ALOT of propellant on very little fission fuel. Lets say we have a 20 ton Lunar fuel shuttle with said 400 kN worth of nuclear rocket engines, It can lift 100 tons of water up, bring 40 tons to low lunar orbit and land again having consumed 60 tons. It could do all that ~29 times on just one kg of plutonium, bringing 1166 tons of water to lunar orbit. So a nuclear thermal rocket might be best for when you need to shuttle stuff from gravity wells that lower thrust higher Isp engines can't do.

What about the residue heat problem? The more the nuclear thermal engine runs the more nuclear waste builds up in it and the longer it takes to shut off and more fuel needs to be wasted to cool it down. It is not hard to calculate how much work one can get. 1 kg of plutonium can produce 83,610 GJ of thermal energy, I calculate that is roughly equal to boiling ~8500 tons of water to ~3500 K (~10 MJ/kg of water), hot enough to get over 450 s in Isp. Of course at least half of that energy is lost as inefficiency of a thermal engine, plus more to run pumps, lost radiation to space, etc, I would say certainly more then 3000 tons of water to >450 s Isp per Kg of Pu should be feasible. For hydrogen it much higher heat capacity per mass means you will "only" get 1671 tons of hydrogen to 3500 K at 100% efficiency, but that is an Isp of ~1050 s.

Is there a way to de-active shadow casting without affecting any other settings? Some script setting? I tried changing shadow setting to zero in the setting.cfg, did nothing.

That is going to be a problem, got to find a place to put it that is easy to get at (not roof) yet no trees above it. I'm thinking maybe wifi it from the septic tank mound so then we can walk out and keep it clean of snow and ice.

Exactly! Someone has got to make those hexagons fit!

On SpaceX news, sort of, Richard Shelby is retiring, he the senator to Alabama that was critical to forcing the construction for the Senate Launch System. Yeah we did that for a time as we had line of sight with the local town water tower and they put up wifi on it, but it was slower then DSL.

[excrement] I did not think about the weather here, we get lots of snow and then fog days in spring.

Well I'm hoping it will be 24/7 reliable up here at 45°N by "mid to late 2021" as it says, it will be a real bummer if it is is not by the time I get it.

I order it, most compulsive buy in my life.

Called my step-father up, told him I want to get him starlink for the family farm, he is paying $180 a month for 2 phones lines and 20 Mbs DSL and he wants to get rid of the phone lines and replace them with Voip (he has been saying he wants to replace them with Voip for years now, needs a kick in the butt to do it). Minnesota is high enough latitude we should get good early coverage.

Oh I did not see that there was smaller ones there, neet

Yes but only on the tube part, not the nose cone where specially sized parts are need to close the pattern.

and the colors of the lights to be saved correctly.

Well the problem is that electrolysis cells are going to get gunched up, thermal cycling is going to cause things to break, contaminates are going to corrode pipes and channels, etc, someone or something smart enough to do complex repairs is required on station at all times to keep things running. I agree that storing and utilizing the carbon and hydrogen is preferable to dumping it overboard as propellant in a ~350 isp solarthermal engine. Oxygen will be the biggest by-product from reducing asteroid material, while not as oxidize as earth rock up to 25% of an asteroid is oxygen, a few percent of that oxygen in Hall Effect Thrusters of ~1500 isp would provide all the attitude control and orbital tuning to put asteroids in high earth orbit via a lunar gravity assist capture, while wasting none of the more precious water and carbon.

Solar to electric is a major conversion loss of energy, but if they are going to go that route, which I think eventually is best, I would think solar-themal-electric would be best so they can still use solar heat for extraction and reforming while also using it to drive brayton cycle generators, which would power electrolysis for recycling hydrogen and carbon monoxide for reducing and reforming asteroid materials into metals, in the process excess oxygen would be the by-product that could then be used in a ~1500 s Isp ion engine. The next problem is thrust to weight: lets say you have 30000 tons of miner and asteroid, and 1 Megawatt solar thermal to work with, a 350 s Isp thermal rocket with 50% efficiency could do 291 N of thrust, and accelerate the whole thing 1 m/s in 1.2 days while consuming 7334 kg of propellant. If an ion engine is used, lets say with solar thermal to electricity efficiency of 35% and Ion engine efficiency of 70% (thus a total of 24.5% efficiency) it would take 10.4 days to accelerate 1 m/s but only use 196 kg of oxygen. I did not add in the added cost of making that oxygen, we need electrolysis cells of at best 75% efficiency using electricity and solar heating in a solid oxide reverse fuel cell, we need to not only boil the asteroid material but melt it in hydrogen gas at 1000 to 2000 K to reduce it to metals and extract much of the oxygen. Lets assume 5% total efficiency cracking oxygen out of asteroid material, that means 2832 MJ/kg for oxygen or 6.4 days needed to make enough oxygen, so 10.4+6.4=16.8 days for 1 m/s acceleration. The biggest problem though is making a complex solar thermal-electro-chemical processing facility that can operate autonomously millions of kilometers away from human operators. These systems will break down a lot especially with god only knows what hydrogen sulfide, ammonia, chloride, protomolecule, etc, content in the asteroid it is chewing up. The pure solar thermal option transastra is working on removes that complexity and thus improves reliability.

They might also get defense funding because their data could also double in detecting impactors before impact. Remember even the little ones can still level a city, 2013 Chelyabinsk meteor was just 20 m wide and did 500 kiloton blast!

There present candidate is an asteroid simulant they launch with their tiny prototype: I agree that what they are proposing is limited to asteroids of high water content if they plan to return asteroid material to earth orbit, but to implement and more advance system that used hydrogen or CO recycling with electrolysis cells and and oxygen ion engines, etc, would take many more years of research and money. For the mean time they claim there are ~600 "economically viable" asteroids of >5 m in NEO for them, if you wish to make a counter study disproving this that would be great.

They claim they will use a C-type asteroid of 10%~20% water in hydrates. NEO of such are still get knocked in from jupiter from time to time.

Yes if this was to be done electrically instead of solar thermal then you have the conversion loses of sun light to electricity (40% max efficency so 60% loss) then conversion to grinders and laser and heater to cook the asteroid material. There is advantage to going solar electric over solar thermal in that potentially asteroid material could be much further refined. Using hydrogen or carbon monoxide reduction asteroid material could be refined and even seperated into metal types, but electrolysis cells are requires to recycling the water and CO2 produced, but oxygen would be produced in such abundance it could be used as fuel in a ion engine. This would allow for almost all the water to be retained (hydrogen) while reducing asteroid material further to metal, but the energy cost would be an order of magnitude more and yet for the same array area only a fraction as much energy would be provided, plus the mass of electrolysis cells, radiators, ovens, and all the added problems that technology provides. 360 s at over 2500 K is perfectly viable, even under performing likely because of low pressures. They are going to NEO that is in earth like orbits with earth like distances from the sun. https://www.transastracorp.com/deep-space-propulsion.html

I have also experienced both the flag and ladder problem in KSP 1.11.0 that I don't experience in KSP 1.10.1.