Shpaget

Is the problem in question your fault? What happens if you don't meet the deadline? Does an entire town end up without drinking water for a month, does somebody die, does the world end, or is it just a matter of somebody else not making as much of a profit? These are the questions I answer myself when faced with similar situations, and usually I end up actually having a relaxing weekend. Who knows what other emergency with unrealistic deadline will happen next Friday, but that too will likely wait until Monday to get looked at. Take care of Number 1 first.

South Korean researchers published a non peer reviewed article regarding a room temp (actually 127°C) ambient pressure superconductor. To make it better, it is also claimed to be very easy to produce in lab from mundane materials. Of course, if this is legit, it will be extremely interesting, bringing a fundamental change to quite a few fields (not power distribution, though, since it's a ceramic, so not suitable for making wires) That being said, there are a few red flags and indications that this may not be as initially presented. Buyer beware. https://qcentre.co.kr/lk-99

But some missions led by NASA (or even their solo endeavors) do include metal detectors. I honestly don't see why you find it unreasonable for some missions to omit this one particular test in favor of others. There are always cost, mass and energy budgets that need to be considered and of course some instruments get left behind so others can have their chance. Why this concern about heavy metals in particular? Sure, it would be nice to know the composition of soil on every landing site, but we already know the composition of lunar soil in general.

So they do participate in lunar landers having detectors for metals. Also worth mentioning that NASA already has 2000+ samples of actual lunar soil, totaling almost 400 kilograms from six different sites.

AM would scale exceptionally well, if you could magic away all the containment issues. There is no lower limit on the amount of antimatter that can annihilate.

While I hate to presume what somebody else meant, I can safely point out that, up until this post, nobody (including you) mentioned anything about spaceships or propulsion. Fusion reactor designs we have today rely on having tiny amounts of fuel inside the reactor that undergo fussion, after which the next batch of fuel is pumped in. This happens very rapidly, but those are distinct events - pulses. It has nothing to do with orion.

You don't think annihilation is hot?

Is it even a testimony? I was under the impression that it's nothing more than "A guy I know told me that his buddy heard about about a guy that read a document."

Pfft, they don't even have FTL tech, they are barely scratching the quantum stuff. Darn it, they think fusion is the future of energy production. They'll never be an advanced civilization. Barely worth mentioning in the next millenial edition of Universal catalogue. -An alien star chart clerk after taking a look at the Earth, all the way from another galaxy

It's gonna take quite a few years and permanent residents before it becomes cheaper to produce metals on Moon than it is to ship them from Earth. In the meantime, there will be plenty of opportunities for someone to take a rover and hand pick more samples in a day than a lander ever could.

So you have 36 km/s of dv. Since "near Mercury" is not really exact, lets have them landed on the surface. They'll need about 20 km/s to reach Mars (using Hohmann). From the original 144, they still have 120+ km/s to run circles around your defenders (or use faster transfer, in which case you decide just how much they have left, or if you want their nav officer to fall asleep at the wheel and then just whisk by Mars without the ability to stop, ending up crashing into The Big Jup).

At work, one of the parts we produce is a tube of about 50 mm in diameter (and roughly as tall) with a wall thickness of about 2 mm almost, but not quite all the way around. There are a few protruding features, which means that have to make it from solid square stock. About 90% of the material is turned to chips. Sure this is an outlier and for a larger runs it might be cheaper to have a thick walled tube custom made, but for a run of a few hundred per year, we just stock up on chip bags.

Lasers can ablate and/or fuse material that is already, they can't deposit new material. Different materials have different absorption properties for different wavelengths so there could be instances where you can use a laser that penetrates surface material and does some work on sublayer made of some other material. For example, electronic traces on smartphone display (while powered on, to boot): https://www.youtube.com/watch?v=ks-lS11TIaY On certain partially opaque materials you can set the laser up so the focus is inside the material and reaches the energy density to do the work, but on shallower layers energy density is not high enough to do it. An example are those tacky acrylic 3d engravings. https://www.youtube.com/watch?v=_wDRXUzfZAw Another way is to hit a specific spot from multiple sides to combine the effect. Radiation therapy for cancer is an example of this, although not with laser but with ionizing radiation. Those are fiber lasers and are 100% real. I've got one in my basement. I haven't really tested it on rust and regular paint (stuff you would find on cars or railings), but it can easily remove some thin paint (maybe its powder coating, maybe it some film type thing) from aluminium business cards I have. It can mark the anodization on aluminium, engrave and cut steel, aluminium and brass. I tried to find something rusty to test just for you, but apparently I keep all my iron stuff well oiled.

For almost ten years I've been hoping he'll keep his word and return, and once in a blue moon I would check, just in case he did. For ten years no joy. Well, today I checked again, and he's back! Zogg from Betelgeuse is back!

Not today, but a few days ago, I got my hands on a brand new fiber laser! A 60W MOPA thingy. It can cut through 0,4 mm alu and steel plate with ease, and even 1 mm brass sheet (took a bit longer). pew pew

Your wish may come true, according to a new study. We may be mere decades from the fireworks, not centuries. https://arxiv.org/pdf/2306.00287.pdf

Metal doesn't need to reach melting temperature to weld. https://en.wikipedia.org/wiki/Cold_welding While this effect is primarily a concern in vacuum, and requires clean surfaces, I don't thing it's too big of a stretch to imagine that such a violent collision would evacuate most of the air at the point of impact, and possibly expose new, clean, material to contact.

Do you really think that a bit of metal tubing is a significant factor in the total cost of modern missiles? Come on dude, a ten second google search will tell you that they cost hundreds of thousands of dollars for even the smallest ones. As for inflatable shells, I would imagine that you'd like your missiles to be capable of steering without folding, and accelerating at a decent rate without collapsing on themselves.

Haven't seen the movie, but the trailer is chock-full of bad stuff. "I've got a shadow moving across the front of the Moon, and it's not Earth." Too bad it was not Earth, it would have saved the studio some embarrassment., but speaking of shadows, that looks like a terminator, not a shadow of another object. "This object is roughly the size of a city." Yet the shadow easily covers entire Moon That shuttle like vehicle takes off without the main engines firing. but keeps all four boosters and the external tank all the way up to the "meteor". They are hit by a giant rock, but deploying a repair bot will fix it, I suppose. Shooting guns at asteroids? If Armageddon and Deep Impact had a baby, and then abused it, neglected it and beat t with a stupid stick.

Factories at 9000 m? I can't imagine that being sensible. Not only you need to haul all the stuff up and down, but so many industrial processes depend on atmosphere, so even if you could provide oxygen for personnel, the machines themselves need air too, so you'll need to pressurize the factories, which is certainly not trivial. But why do it anyway. Not even Japan, the stereotypically crowded country is in such a short supply of space to need this.

To be fair, cruise ships have a whole bunch of stuff dedicated to unnecessary luxury, while a generational ship would probably lack all the casinos and shopping malls and as a whole look a lot more like the crew quarters of the cruise ships than the passenger areas.

If an approximation, even a darn good one, was a satisfactory answer, there are simpler solutions and we wouldn't even be having this discussion. The point is that it's impossible to get the exact value.

Squaring a circle is problem of constructing a square with the area of a given circle using only a compass and a straight edge. What you said is a bunch of words that form almost, but not quite, gramatially correct sentences, yet lack in any coherence and meaning, while introducing concepts that have absolutely nothing to do with squares, circles, areas, straight edges or compass (most of which you fail to mention at all).

ITERs tokamak is quite a bit larger which is quite a factor when it comes to pressure vessels.

Can you elaborate?