Itty-bitty Living Space

Okay so the power in question isn't really "phenomenal" or "cosmic".

But anyway I was thinking. Can you beam power to nano-bots? They're smaller than the wavelength of microwave-power transmission; a dipole antenna is about half a wavelength long, so even if you made the entire length of a 500-nanometer bot into an antenna, it'd still only be able to receive wavelengths of up to one micrometer (can you beam power in the near-infrared?). Fractal antennas, maybe?

The frequency recommended for microwave power-transmission is 24 GHz, 12.5 millimeters wavelength. Apparently an "electrically small" antenna is one whose maximum dimension is less than the wavelength λ (specifically the "free space" i.e. "propagating in vacuum" wavelength but "wavelength" simpliciter, for our purposes) divided by 2π. 12.5 millimeters over 2π is 1.989 millimeters, which is to say "almost exactly 2"; the maximum dimension of a 500 nanometer bot is λ/25,000. Is that feasible in an antenna? I doubt it; you'd probably have to pack it pretty tight.

Another option might be ultrasonic power transmission. You can use that for all kinds of things; it might some day replace microwaves not only for wireless power but for at least some data, though of course it's totally worthless for a spacefaring civilization. (It's apparently subject to jamming just as EM is, which is fortunate.) And in air at room temperature, the frequencies at which ultrasonic power-transmission works (45-75 kHz) have much shorter wavelengths than those used for microwaves—4.576 millimeters to 7.627 millimeters. That means much less space is required for the receiver (though I wonder if there might be "noise" issues—literal and figurative noise, given we're talking sound waves—at the nanometer scale).

I guess I'll go with ultrasonic power-beaming, for my weaponized nano-bots. It occurs to me that since zledo can hear sounds up to 65 kHz (same as tigers), this choice gives me plot options. (It also gives me an excuse to keep the humans using EM for power transmission on one of the planets—that the sunspots of a BY Draconis variable play hell with EM transmission is an important facet of one of my characters' backstory. Then again ultrasonics, in the frequency-range and decibel-levels (145-155 dB) involved in wireless power, don't seem to be much use for transmission beyond about 1 meter per decibel—at room temperature, and depending somewhat on humidity and air-pressure.)

Medical nano-bots, of course, can be powered from their host's body in various ways, e.g. by heat, blood-flow, borrowing some of the body's electrolytes, etc. (Maybe while undergoing nano-bot treatment you have to drink lots of Gatorade.) So I probably don't have to worry about that.


War Never Changes III

Military science fiction thoughts.
  • Apparently "gray goo" is more or less impossible; biological materials (as distinct from "organic materials" as such) are too complex to be easily incorporated into nano-bots. Also there's the fact that nano-bots are too small to move around much; at their scale, drag is apparently crippling.

    There's actually a simpler problem: at the scale of a 500 nanometer bot, moving one meter is the equivalent of moving a DJI Phantom quadcopter drone 1,150 kilometers. Apparently ten to twenty is considered relatively long-range for those. That problem might partly go away if you can beam them their power, I suppose.

    I think you can still weaponize them, but, only small-scale. You basically have a precision-targeted form of germ-warfare, or possibly something that can eat the concrete and rebar from your enemy's bunkers and send them crashing down on top of him. (The former is still probably ethically questionable; the latter is insidious but probably okay.)
  • Someone was talking about what it sounds like to vaporize (they said "disintegrate", but vaporization is the easiest way to accomplish that) someone's limb. And I said, "Boom."

    Because, to vaporize a human, bones and all, takes 3 gigajoules, equivalent to 717 kilos of TNT. Therefore, by the "rule of nines" (or actually "of elevenths"), to do it to an arm takes (9% of 717=)64.53 kilos TNT, and a leg would take (18% of 717=)129.06.

    That means that vaporizing someone's arm is roughly equivalent to hitting him with an AIM-7 Sparrow air-to-air missile with an RDX warhead (40 kilos of RDX is 64-odd kilos of TNT). In the arm. Probably would've been simpler to just shoot him.
  • Just decided, just like how zledo don't distinguish tanks from other artillery (referring to them as "armored guns"), and their space-force is a branch of their artillery, they also consider their air and naval forces to be artillery (air and sea, basically). After all, what makes naval vessels (apart from aircraft carriers) important is their guns and missiles; what makes air a factor, militarily, is bombs and missiles. Interestingly, there has been machinegun artillery, like the Bofors 40 mm autocannon—and it, like aircraft autocannons, is mostly used in an anti-air role.

    I think the org-chart for zled artillery is basically like the US Navy, and not just because they crew spaceships. You can think of a single artillery emplacement as being something like a single boat, a large group of them as like a large ship or a fleet; the logistics aspects are similar as well. About the only thing that's different is the actual "self-propelled vehicle" aspect, and that, too, is arguably comparable to the drivers and mechanics in a mobile artillery unit, or the power-plant and similar jobs, in a fixed base. I think their "Air Force Bases" are actually more like carrier aviation that happens to stay in one place, too.

    And then, of course, their ground forces (I'd wanted to say "infantry" but really "infantry and cavalry", at least historically though they still use pack-animals), which in their military has a subordinate role to artillery (as it did in every Western military at least from Napoleon on, if not longer), is like the Marines, who are a branch of the Department of the Navy. You do need infantry to make artillery effective; not only are guns worthless if their crews get overrun, but a guy with a heavy machinegun can pin down enemy forces long enough to bring in fire support (of which even we consider close-air support to be a sub-set).
  • Is it just me or do personal force-fields make no sense? I mean, how's it work? It can't repel most bullets magnetically, they're not ferrous. Gravity-based tractor beam?

    Hmm. An M-16's NATO-standard ammunition is a 4-gram bullet moving at 940 m/s. Suppose the force-field starts working in a two-meter radius from the user, and stops the bullets by the time they reach a one-meter radius. To stop a bullet fired from close range (where it's still moving roughly at its muzzle-velocity), in one meter (which the bullet will cross in 1/940th of a second) means an acceleration of 883,600 m/s2. That acceleration, applied to a mass of 4 grams, is still 3,534.4 newtons.

    That's as much force as accelerating an average adult human (62 kilos, taking both sexes into account) at 57 m/s2, or 5.81 G's. So your personal force-field means flinging people away from you at the equivalent of "zero to sixty in .47 seconds". (You'll recall that the Goa'uld personal force-fields, in Stargate SG-1, address this, and only work on objects moving above a certain speed. But I question the usefulness of a defense-system that doesn't protect against tomahawks.)
  • The average (adult) human male is 173 centimeters tall, while the average female is 160. Thus, the average adult human is 166.5 centimeters tall. The average man masses 70 kilos, the average woman 54; the average is, as mentioned, 62 kilograms. If humans were made of automotive alloy (guessed where I'm going with this?), they'd mass 105.283 kilos, 125.283 if they were also wearing full-body steel plate armor. And if that armored figure were ten meters tall, it'd mass 27,142.47 kilograms.

    The 100-kilogram DURUS/PROXI robot uses 2.2 kW⋅h (7.92 megajoules) every eight hours; if it were the ten-meter, 27.14 megagram mecha, it would use 597.13 kW⋅h (assuming power-use scales linearly with mass). That sounds terrible, until it's pointed out the M1 Abrams uses the equivalent of 10,020 kW⋅h over the same period. And there's 40% of the land-surface an MBT can't go on, whereas a mecha can, on nearly all of it. (Of course, the only way the mecha can beat the MBT is by using missiles...unfortunately for the tank, the mecha's modularity means it can use missiles.)

    Basically, I think I just invented the guerrilla tank. Provided the guerrillas have some mad scientists handy, anyway. Indeed, the backstory of my mecha involves them being used for precisely that. (It's a lot more plausible than "Minovsky particles", anyway.)
  • In some ways it's like reality is doing us a favor, writers I mean. Consider: while soon the only manned air combat will be close-air support, that's also the easiest to write and the least counter-intuitive kind. (CAS is also the only air-combat you'd be likely to use mecha in.)

    Or how at the ranges space-combat happens at, "close enough to control in real time" is practically the same thing as "on board", so there's no reason not to cut out the middle-man and just use manned spaceships (AI probably never reaching the point where you'd trust it with nukes).
  • Speaking of nukes, what's with this idea that space combat would involve something else? Use anything weaker in your missiles, and that fuel is probably better spent carrying more ammo for your KE weapons; and anything more exotic is going to be too big to schlep into space or too expensive to waste on a warhead. (Maybe something fragmentation-based.)

    That said, I think my setting's humans use antimatter to catalyze fusion in their bombs, whereas zledo can miniaturize topological confinement enough to make true pure-fusion weapons. The former, unfortunately, is volatile—antimatter containment is a bitch—but, I mean, you're not any less dead with a "magazine hit" involving far more conventional weapons.
  • Something occurs to me, RE: zled artillery. Given they can throw a small car (their women can flip one), they can pretty much manually load even the 750-kilo shells fired by giant things like the Soviet 2B1 Oka or the Atomic Annie nuclear howitzer—let alone the little 90-kilo shells the M110 fired (and not even bothering to bring up the 47-kilo shells the M109 fires).

    On a related note, part of the problem with putting (human) women in all the same roles as men, in the military, is they physically can't "hump" a lot of the equipment. A lot of the people pushing for a unisex, fully-coed military have bought into the fantasy of "push-button war"—which, again, even Hideo Kojima knows will never actually happen.

    Hideo Kojima having a more accurate conception of military realities than you do is a kind of shame a culture would invent harakiri to cover, even if it'd never had the practice before.