That's the thermal battery. The reactor core itself is cooled by liquid sodium metal. Sodium is a nice reactor coolant because it only produces one short-lived isotope (which in turn decays to a stable isotope) but it is still literally liquid sodium metal so keeping it dry is essential. Designs that run the sodium metal loop through a water loop to drive a turbine are inherently pretty spicy.

The Natrium design puts a sodium salt as an intermediary -- the sodium metal dumps heat to sodium nitrate, sodium nitrate dumps heat to water, spins the generator.

This is nice because it means you can run the reactor at its highest efficiency all the time and use the salt as a buffer to vary electrical output. It also means you don't have water and sodium adjacent to each other -- you can actually put them quite far from each other.

Yes, corrosion of the reactor coolant system in particular seems like it might be a major challenge. Material science has gotten better, so maybe it's okay now? Anyhow, it's hard to test without building the thing.

This is one reason they make flexible adapter cables instead of just rigid dongles.

At one point I read an analysis (I can't find it now, alas) that figured the biocharring process releases enough heat that it's approximately break-even with sewage, even once you account for water evaporation. I'm not sure if that was purely for biosolids (even after separation, they're pretty wet solids), or if it included liquid processing as well.

Another place these plants could make a lot of sense at is livestock farms. I know that at dairies, "where can we put all this cow poop?" is a fairly major ongoing concern. There is just a huge amount of it. Waste lagoons (yes this is a real thing) are... not super great solutions to these problems. Not every farm location has great siting for them, and things like "oops there was a flash flood and the waste just dumped into whatever was nearby" and "oops the liner had a leak and now the ground water is full of poo" are not particularly uncommon.

Also, the problems with livestock-related antibiotic resistance are probably substantially larger if we take the waste (bacteria and all!) from the livestock, mix it with other bacteria, and spread it all over our environment.

Making this stuff somewhat less problematic (as well as smaller!) would be really excellent.

When you're making biochar, you try to avoid belching much exhaust into the environment; you want to convert your input into charcoal, not turn it into CO2. So things like plastics and pharmaceuticals get charred and rearranged more than turned into smoke. And in any case, coal has taught us to be very good at cleaning particulates out of smoke.

As other people have mentioned, heavy metals can be a problem when biocharring landfill waste; they're not likely to occur much in sewage, though.

Finally! What do you think happens to human waste now? As of 2013, in the US, more than half was treated and used as fertilizer; most of the rest was landfilled. (For some reason, we have mostly decided "just dump it in a nearby body of water" is a bad plan.) Both of these methods happily release microplastics and pharmaceuticals into the environment. Plus, if processors are... less-than-scrupulous... about treatment, it can be a source of disease outbreaks.

Anyhow: We need to do something with all the human waste we create. Turning it into biochar is, on balance, probably better than anything else we can do with it. It's non-infectious, not smelly, gives us a useful end product, and greatly reduces the amount of undesirable other stuff in the mix.

Why is it poorly understood? Sounds like a phenomenon itchin' to be studied.

Studying it would be expensive and the "don't put electronics in extreme radiation environments" solution to the problem nearly always works.

Not saying as it isn't cool; it sounds cool as hell to figure out. But there are only so many people to figure things out...

"Professor" means very different things at different universities. There are universities (often what people refer to as "small liberal-arts schools") where professors teach most of the courses, and getting tenure is much more of a "can you teach students?" decision. At research-focused universities (usually larger institutions), professors often don't teach many of the courses, and getting grants and being able to successfully manage a lab and coach graduate students are weighted more heavily in the tenure decision. In any case, where you get your PhD (and postdoc) are huge factors in whether you'll get a tenure-track position -- about 20% of schools produce about 80% of professors:

https://www.nature.com/article...

Either way, there are many more PhDs awarded than there are professor positions available; most people with a doctorate will wind up in industry just by the law of averages. The less-realistic amongst them may spend a long time as adjunct faculty, teaching heavy course loads for punishingly low wages, before going into industry. I know this is not, like, 100%, but I generally hear "I'm taking a job as an adjunct" as "I will never get tenure but I have not admitted it to myself yet."

If you're in a PhD program or postdoc and want to get a tenure-track job, it is worth having a frank conversation with someone you trust about your prospects and what you can to to improve them.

People have thought about this; lunar lava tubes are a theoretically viable space for long-term lunar habitation. We probably could do it at today's technology levels, though of course we haven't tried it.

Still: Maybe show me a self-contained habitat with multiple humans living for multiple years on Earth before getting all excited about that prospect on another planet. This should be super easy and cheap in comparison (everything we need is right here!) but we have yet to manage it.

Measuring expected and actual thrust from firings, and then running through a root cause analysis when those numbers started not matching up.

Sigh, GPGP. Why does my brain do the typo over and over again

To a first approximation, the GCGP is made up of fishing and construction debris. Buoys alone make up nearly 60% of the patch, by weight. All single-use plastics make up less than 15% of the patch. Source: https://www.ncbi.nlm.nih.gov/p..., Table S2.

Not saying as we shouldn't reduce single-use plastics, and keep them from winding up in the ocean — we absolutely should! But accountability for the fishing industry is where the margins are for eliminating the GCGP.

And that's super hard —a ton of fishing takes place in international waters, with an industry operating on razor thin margins, outside the easy observation of regulators, and where a bunch of the governments in charge of regulation don't give two shits about a patch of trash in the ocean anyhow.

Fishing is a $320B industry in the US alone. Spending 1% of that annually to improve fishery habitat seems like an eminently reasonable thing to do -- removing the GCGP and keeping it gone on an ongoing basis would be a very worthwhile way to spend some of that money. And getting other Pacific-bordering nations to cooperate on that front would also be a pretty reasonable thing to do.

Thing is, sometimes when those bullets and missiles start flying, it's a surprise! And while those 18-25-year-olds may think "it's worth that risk" they don't get to make that call. The mission is to provide an effective, survivable naval force for the US.

There's the old list of steps to not die: "Don’t be seen. If you are seen, don’t be targeted. If you are targeted, don’t be hit. If you are hit, don’t be penetrated. If you are penetrated, don’t be killed."

Operating a radio network with whatever-the-fuck-devices blapping GPS coordinates to whatever-the-fuck commercial services can really impact the "don't be seen" and "don't be targeted" parts of that defense strategy.

Yeah -- you don't need to make currency counterfeit-proof, you just need to make it resistant enough that it's not economical to make counterfeits you can pass off without getting caught.

American currency has a lot going against it (eg, all our paper bills are the same size and printed in roughly the same basic color scheme, so things like turning $1 bills into $20 bills are more possible than with European or British currency) but even here you still need to invest a lot of time and money into doing a decent job of it. And ultimately... there are easier ways to grift that have much less stringent punishments.

This point seems ambiguous to me. I'm not sure if this is a "if you modify an AGPL product, you must share the source to the product, even if you are only using it as part of a service" or if it's "If you use an AGPL product as part of a service, you must provide the source to the AGPL product as well as your service."

Regardless, it's pretty much a moot point. OpenSearch exists, is wire-compatible with ElasticSearch, and has a thriving developer community and an unambiguous, well-tested license. I struggle to think of a reason why someone would choose ES at this point.

I actually don't think it's ridiculous for the FAA to ground aircraft and spacecraft when there's an unplanned loss of vehicle. This will very likely be a short grounding while SpaceX says "there's no danger to the uninvolved public on these missions, we'll do an investigation before we fly anything with elevated risk."

In particular, it's important to make sure whatever caused this loss is not an early marker of something that could cause range safety issues on future flights.

Also: While they do land normal F9 launches offshore, for F9 Heavy launches, they fly two boosters back to the Cape.

Also also: While this should not factor into anything, Musk's penchant for giving regulators a vigorous middle finger probably does not encourage them to let things slide or hurry things along.

Not saying as NASA is blameless here, but it is very much worth looking into Congressâ(TM)s role in all this.

Itâ(TM)s hard to run an efficient space program when the organization that funds you is continually asking for stupid things and requiring that you do them in stupider ways.