pfdietz

17 ms·

451.
by pfdietz 4mo ago
Once it's in orbit the cost of moving it farther out needed be very high. Just evaporating it with solar energy in very high orbit will allow the solar wind to carry it out of the solar system.
452.
by pfdietz 4mo ago
And the armored waste carriers to fall back to Earth and be recovered for relaunch.
453.
by pfdietz 4mo ago
I don't think that's the case, if launch costs are low enough. The options you describe there are quite expensive. Reprocessing costs somewhere in the neighborhood of $1000/kg. Even fast reactor have trouble disposing of th
454.
by pfdietz 4mo ago
Fusion's main accomplishment will likely be to make fission look cheap in comparison, due to fundamental issues of power density in the nuclear island. Why make a huge complex low power density radioactive thing when you can make a mu
455.
by pfdietz 4mo ago
IMO, the long term solution will be to simply launch the waste into space. With low enough launch costs the extra mass needed to armor the waste against accidents becomes tolerable.
456.
by pfdietz 4mo ago
Microreactors have been tried before by the military, for use at bases, which have guards. They not only didn't make sense to install, they didn't make sense to continue to operate once installed.
457.
by pfdietz 4mo ago
We don't actually know how much that cost France, sine it was mixed in with their military nuclear effort. French auditors threw up their hands trying to figure out the actual costs. What we do know is their attempt to build more NPPs
458.
by pfdietz 4mo ago
Cost is not only relevant, it's paramount. Efficiency is only important insofar as it affects overall cost. Diesel generators have the advantage of being very cheap -- an order of magnitude cheaper than NPPs per unit power output -- a
459.
by pfdietz 4mo ago
> microreactors don't seem to have any inherent disadvantages They have diseconomies of scale. Some of the costs of a nuclear power plant scale sublinearly with power. Neutron economy is improved in a larger core. Larger turbines
460.
by pfdietz 4mo ago
> Why would microreactor concepts not be suitable for commercial use? Crippling diseconomies of scale.
461.
by pfdietz 4mo ago
Nuclear is not on a trajectory to do more than supply a minor amount of world energy. A (say) 10% nuclear, 90% renewable world is not an easier challenge than a 100% renewable world -- the intermittency/seasonality issues aren't
462.
by pfdietz 4mo ago
Nuclear partisans like to call renewables ideological, but I think this is another example of "the accusation is a confession". The empirical evidence has nuclear being uncompetitively expensive. The current focus on variant reac
463.
by pfdietz 4mo ago
TRISO increases fuel cycle costs. It's harder to make, harder to dispose of, and (IIRC) uses higher enrichment.
464.
by pfdietz 4mo ago
Yes, those are utility arguments. So don't we get more utility if AI now spews out lots of new math results?
465.
by pfdietz 4mo ago
The concern in the impact is how much heat is produced in the material itself, by the shock wave. A shock wave is dissipative, producing entropy and heat as it propagates, but near the spalled surface it cancels itself out and the heating
466.
by pfdietz 4mo ago
Certainly a great deal of energy is released. However, on the time scale of an impact, heat doesn't diffuse in rock very far. Even on the time scale of reentry to an atmosphere heat doesn't diffuse far. It's common for a me
467.
by pfdietz 4mo ago
I don't see how it could be interpreted that way. Please explain.
468.
by pfdietz 4mo ago
> By what mechanism. Impact spallation. When the strong shock wave generated in rock by an impact hits a rock/atmosphere (or rock/vacuum) surface, it is reflected, producing strong tensile stress. This causes very large accele
469.
by pfdietz 4mo ago
That is the question, yes. But if lithopanspermia is a thing, we don't need to go to Mars to investigate that question: we can look for this variant biochemistry life right here on Earth. This sounds to me like a valuable and econom
470.
by pfdietz 4mo ago
Suppose we create a database of (say) 5 million AI generated inventions. Against the claim that this wouldn't be searchable, we can just observe that this is about the size of the US patent database. Does this mean patents are not sea
471.
by pfdietz 4mo ago
> My point was that it’s hard to imagine citing something that could not be patented as prior art. There is no need for it to be patentable (or patented). Prior art only requires that it be described and be made publicly available. It
472.
by pfdietz 4mo ago
The Fermi Argument.
473.
by pfdietz 4mo ago
It would not be surprising if ancient life did exist on Mars, since impacts would likely have sent life back and forth between Earth and Mars (and possibly Venus). For the same reason, the existence of ancient life on Mars would not show th
474.
by pfdietz 4mo ago
I understand that for the 747, they initially just had a cockpit bulge atop the fuselage. However, this created too much drag, which they reduced by extending the bulge aft. They didn't need this space for flight operations, so it wa
475.
by pfdietz 4mo ago
It would be great if Musk bought an orbiter and made an honest display about what a boondoggle the whole program was. SpaceX's success shows the shuttle was seriously the wrong thing to have done. It would have been much better for N
476.
by pfdietz 4mo ago
> wouldn't there be a way to hide such cheats in it? No.
477.
by pfdietz 4mo ago
Prior art doesn't have to be a patent. A frickin' Soviet movie was prior art in the Blue Origin/SpaceX lawsuit about landing rockets on barges.
478.
by pfdietz 4mo ago
Or they might conclude "even an AI could come up with this, it's obvious". Obviousness is a defense in patent law, not in copyright law.
479.
by pfdietz 4mo ago
You think those people in low income countries would prefer what they were doing before? Then why do they take these jobs? Is someone holding a gun to their heads? Don't compare these jobs to some unattained ideal, compare them to th
480.
by pfdietz 4mo ago
https://www.smbc-comics.com/comic/agency

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