Sci-fi Weapons, Vehicles and Equipment

Blood agents are the boogeyman of the US Army Chemical Corps. They go through JLIST MOPP gear like it's paper.

In a future setting, lethal agents are a weapon of denial and/or terror. Think about it, they would contaminate crops, equipment, the ground, living spaces but most chemical gear would keep troops and civil defense alive. Against an unprepared civil populace? Very deadly.

Non-lethal weapons could find a place in crowd control and in making enemy forces surrender. A sleeping gas for example.

But the line between "less than lethal" and "war crime" is very thin.

• A gas that knocks people out could cause people to suffocate, or could be lethal to people with condition [INSERT MEDICAL CONDITION HERE]

• And if their are aliens in the setting? They may breathe the stuff, it might kill them but the dead could cause further contamination....

• Or the aliens might be pissed off and are now in a killing frenzy.

For a Type III civilization whose superweapons are capable of setting off supernovas, would a Thing-like organism that has assimilated other Type II and III civilizations and learned how to build and use their technology be considered a threat, or would that civilization be so far beyond untouchable that nothing except themselves would be able to kill them?

Tom: From the several people I have talked to there lots of times where they were not in MOPP gear. I am sure spattering the rear area where all the food, ammo, and other supplies would be...unpleasant even if everyone were already in PPE. You are also more likely to catch people outside of their PPE.

Taira: Oh god I forgot about blood agents. The substance that eats gas mask filters by rapid exposure saturation. Even worse all of them are lethal in very low doses.

I know the Russians used that "knock out" gas on the theatre and killed a bunch of people in the process.

Anybody got any Space Station ideas for an Orbital Defense Grid?

Thick smoke might dampen a momentary laser pulse entirely but a continuous stream would keep vaporizing particles until it got to the target. Ablative armor would be a better defense as lasers are notoriously inefficient.

What about a hybrid defence in the manner I've described here in the past? A type of armour that ablates into a thick anti-laser aerosol when struck by a laser. The more armour it ablates, the more aerosol it has to penetrate, weakening it still further.

If I remember correctly, during the NATO intervention in the Balkans didn't the Serbians manage to trick NATO aircraft into attacking false targets by placing a heater inside a fake tank so that on IR displays it looked like an engine was still running/had been recently on (hence enhancing the illusion)?

Admittedly there's no guarantee that would still work on future IR systems, but unconventional tricks like that are at least worth thinking about.

Interesting. So judging from your comments (and those of Teufel), it seems like the most likely result of hitting something with a railgun fired APFSDS type round would be a catastrophic kill.

Would it be possible to convert other types of tank rounds - such as canister - to railgun use? And perhaps more pertinently considering the above, anything that could be done to defend against such rounds? Or would the only defence really be "don't get spotted"?

A few thoughts occur to me.

• The agent should kill extremely quickly at very low exposure levels. This limits the amount of time those exposed to it have to protect themselves.
• The agent should also be capable of persisting for long periods of time in all weather conditions whilst retaining its effectiveness.
• It should spread quickly, but not so quickly that friendly forces will be unable to react if winds change and it begins moving toward friendly lines.
• It should be extremely difficult - or at least time consuming - to decontaminate people, vehicles, structures, etc. that come into contact with this agent.
• Preferably, it should be able to defeat contemporary chemical defence measures.

Furthermore, it should also be subtle and leave little to no indication of its use. In an environment where you may be preparing to use chemical weapons first, the longer you can deceive the enemy as to the true nature of your ordinance the better. This means that its symptoms should be minimal, and its delivery system must not clearly indicate that a chemical weapon has been deployed. That is, an air delivered munition or artillery shell should not obviously "puff" open and spray the area with droplets - if possible, it may be desirable for the munition to behave like a dud explosive whilst allowing its contents to percolate into the environment.

Subtle, non-indicative insertion techniques are the name of the game.

The question of defeating anti-chemical weapon measures is a tricky one. One possible solution I came up with is a "nano-fog"^note Probably not literally nano-scale, just trying to get across how small the droplets are that can bypass filters because the droplets are too small to get caught in it.

Alternatively, degrade their protection as preparation for the employment of chemical weapons (for example, drop incendiaries on an enemy infantry position to burn or at least damage their protective suits or powered armour... and then drop chemical agents that can withstand high temperatures - or better still, agents that become toxic at high temperatures). But that's admittedly a bit iffy (if you can damage their suits through another method, why not just cut out the chemical warfare entirely?).

Lethality isn't always necessary, and in some cases isn't even desirable. Think about this, a dead soldier at most has to be carried home and buried, while a live one needs medical attention, and put enough soldiers out like that and the enemy's support gets clogged up. Evacuating a live soldier is more difficult too, a dead one needs maybe 15-25 kg of coffin, a live one, 50-80 kg of bed, plus support staff, plus equipment, etc.

Canister and other solid round ammunition, hell yes. Explosives? Only if you dial back the acceleration power. Otherwise the explosive element is wasted.

Defending against such things is pretty much the realm of either hit a railgun round with another railgun round to deflect or obliterate it, use a barrier of sufficient protection (NOT ARMOR) preferably a big heavy mountain under/in front of you or Deflector Shields, or yes not getting fired upon in the first place.

That was one of the (alleged) advantages to intermediate ammo in The '60s. Wounding an opponent makes the enemy spend more than replacing somebody. Very World War Two logic but it was there.

Except historically it never worked that way, broken and obsolete logic right from the get go. Few people ever gave a shit about battlefield wounded. Those that did were taken advantage of by their enemies who would chuck their wounded onto them forcing the cost away. (Viet Cong, NVA, Taliban...)

Soldiers who tried to use this method often ended up either disappointed or killed. Soldiers who didn't often complained (and continue to complain) of insufficient stopping power of their weapons.

I was talking about in regards to nerve agents, not conventional weapons. A further bonus to the attacker is that sub-lethal doses are simply weaker versions of lethal doses, so you can hit more troops with them than with lethal doses.

edited 26th Nov '14 4:34:38 PM by MattII

Except it's the same logic. Not a lot of enemies are going to care about battlefield wounded and poisoned. Instead they'll dump em off on their enemies who do care (and presumably launched the attack in the first place). Or worse, they may not be able to handle those wounded and poisoned so they die anyways.

And there's no real defining line between a less-lethal dose and a lethal dose when it comes to chemical agents. A lot of folks will be killed by the small doses so you might as well go whole hog and just use the always lethal dose. Which defeats the idea of using the same amount to hit more.

edited 26th Nov '14 5:05:39 PM by MajorTom

If I can dose everyone in an area of 2 km^2 and kill them, or everyone in an area of 5 km^2 and leave them as shambling wrecks, I'll do the latter, more cleanup for me, but the enemy loses way more guys.

Saber: That isn't really defeating or hiding thermal imaging so much as creating a decent dummy target. You can see shape detail to a point even with temperature difference. You can see guys carrying kit in many modern gen thermal targeting cams. If you heat up a tank hulk the right way and look at it using only thermal it will look like a hot tank. That particular trick is used to test IR and thermal targeting. That is more decoy then defeating thermal or hiding from it. That is more like using flares to make the thermal or IR signal bigger and hope its good enough.

As it is I seem to recall laser missile dazzlers are becoming the way to go for IR or thermal targeting protection. They flash the sensor and hope to at least temporarily blind it.

As for less then lethal chemical weapons those have been around for a while. CN, CS, and variety of other agents that were meant more to incapacitate rather then kill. Same for bio weapons. There are varieties of both that are generally meant to cripple or incapacitate with low lethality.

In theory, but it will never be that way in practice. Chemical munitions are laughably unreliable in their dispersion effects. Airborne chemical munitions are easily defeated by crosswinds and liquids are often ineffective because of rain or the effects of urban terrain or slopes. A lot of chemical munitions require a significant concentration to do significant harm to a single soldier. A ziplock bag filled with liquid Sarin will kill you Deader than Dead as happened to that maintenance guy in the Tokyo subway systems back in the 90s but it has very limited effect on others. Disperse that same amount airborne and you can affect more people but the results are unreliable and unpredictable. It may concentrate in a single area, disperse too diffusely to do much harm, a thousand scenarios can happen other than the ideal all of them vastly more probable.

Some of the reasons why chem warfare is laughably rare since the First World War.

A small question: how much friction heat can a non-aerodynamic humanoid mecha realistically expect while flying (horizontal flight, not reentry) at hypersonic speeds through atmosphere similar in density to Earth's? Would it be enough to melt off the armor without an ablative heat shield?

Define hypersonic speed. Quite a few aircraft currently (or previously) existing could hit pretty high on the Mach scale and not turn to a molten block of slag while in forward flight.

And I'm not talking Mach 3.

While shaping does help, the materials play a lot into how much can a design take.

The Mig-25 and the F-4 were "the triumph of thrust over aerodynamics".

If the Mech is made of Unobtanium, anything goes. Just admit that your mech has all the aerodynamics of a brick.

edited 27th Nov '14 8:57:04 PM by TairaMai

ICBM's hit hypersonic velocities easily and don't melt. They are not exactly that heavily protect either.

You have to be going pretty high on the Mach Scale to have that be a concern. Somewhere roughly between mach 10 and mach 25.

^ Closer to Mach 25 as you're nearing escape velocity on the high end of the 10-25 range. (Beyond Mach 25 is re-entry/escape velocity speeds.)

No that is the correct range. Mach 10-25. That is where things like special design considerations for serious heat build up are required. That would be exposed components must operate at rather high temperatures or otherwise be shielded. Over Mach 25 you are talking re-entry speeds.

^ And I'm saying you'd need to worry about those effects and needs more towards the higher end of that range. At Mach 12 you're not gonna be a blazing ball of fire like a meteor, it won't be that much different than traditional hypersonic. At Mach 19, you will be brighter than a Christmas tree on IR cameras but still nothing in the visible spectrum. At Mach 23, you might actually be visibly glowing from heat effects significantly.

No you need to worry about that before a lot sooner then the high end. This is nothing like the lower mach speeds at all. Heat build up starts happening before you even reach mach 10 well before you even get close to mach 25. You already need special considerations for construction and materials at mach 5-10. At mach 12 your craft is going to be a lot notably hotter then the lower mach ranges. Again your design either needs to be able to run really hot or you have to start shielding it. You can't argue around this one tom,

edited 27th Nov '14 10:14:57 PM by TuefelHundenIV

I read somewhere that the heat generated by re-entry mostly isnt due to friction anyway.

It's actually more compression than friction. The spacecraft is falling so face that the air can't displace properly so it compresses rapidly. This also means that as much heat the craft is under, it's also under just as much physical pressure.

^ Compressional heating is the term. Its effects are seen in surface weather where you can be heated up 10-50 degrees Fahrenheit over the span of a few days before a storm arrives.

Tom: You get compression heating, NASA calls it aerodynamic heating, below the mach 10-25 speed ranges to begin with. You get it supersonic/sub-hypersonic speeds as it is never mind you start to see it at speeds approaching the low end of super sonic that is less then mach 10. We see the proof in the rail gun tests which had air compression and heating to the point of causing lensing and a plasma tail until it slows down below the thresh hold for it form. That was the less then Mach 7 test bed round. What do you think is going to happen when they push that speed even higher?

A more pertinent and notable example being the SR-71. It suffered chronic heat issues including heat expansion because it got so hot at speed and left a heat trace that was easily detected at long range. It never got past mach 3.5 never mind low hypersonic. It's design needed to incorporate special features to prevent overheating of the exterior components, via the fuel heat sink under the skin, and allow for the thermal expansion of the titanium skin. To top it off it was so hot at speed it could be tracked for hundreds of miles on heat alone from the body heating and engine heat.

Further proof is the design considerations in the Wave Rider hypersonic test bed. It needs special design considerations and construction work at hypersonic speeds and that included dealing being heated up by the speed of it's travel.

That you need to take consideration of designing certain features at high mach speeds from high heat resistant parts at a minimum to heat shielding at the more serious heat levels, especially in the ranges from 10-25 never mind 25+, fits in with everything we know about heating and high velocity air travel contrary to what you have stated.

edited 28th Nov '14 6:36:49 PM by TuefelHundenIV

So if we change amitakartok's question to "How much compression heating etc., etc., what's the answer?