[UT] Help! Future Combat Revolving Around Ultra-Tech Stabbery

[Seneschal]

So, me and my players are fleshing-out an upcoming TL11 space opera campaign and getting all the world details right. We're going for a slightly comedic campaign set in a relatively hard-sci-fi setting. While the core technologies aren't completely realistic, we're aiming for internal consistency, so I'd like to have clearly defined limits and capabilities for each of them. I'd appreciate if the hive mind here could stress-test them, and see how you would use them most efficiently, what exploits you would find, which technologies have obviously better alternatives that I've overlooked, etc.

In order to get the right "feel" of the combat (a bit more survivable, close-ranged, highly skill-based), I've set up the following premises that are supposed to shape the setting in favour of certain combat tactics. They are all subject to change; please let me know if you have alternatives, disagree with any of these, or think they would result in something else.

• Environments: The setting lacks "garden worlds" and magically-fast terraforming. The majority of humans live in self-sufficient arcologies or space habitats with extremely high population density; thanks to nanofabrication, each community is completely independent, and often a sovereign entity. Known space is dotted by thousands of micro-nations. Combat often occurs indoors, on ships, stations, or mega-buildings, and sightlines are rarely longer than 5m.
• Personal Barriers: Introduced some 50 years ago, personal forcefields are compact and affordable. They grant the wearer DR 70-100 (Ablative; Hardened 5) - it recharges by 10% every second (technobabble: the phlebotinum fields are completely impenetrable, but they are bottlenecked by the power capacitors). They hug the body closely, and are permeable by objects of sufficiently low velocity (see main issue, below).
• Weapons: Weapons tech is somewhat hard-science - no outlandish disintegrators or gravity beams exist; kW-range handheld lasers are common, but because of the aforementioned crappy capacitors, doesn't have large RoF; projectile weapons are weaker, faster, and include smart matter (to change shape and fire a wide array of calibers) and nanofabricators (for manufacturing their own ammo on the spot). In either case, the survivability of a typical combatant against these weapons is greater than that of a modern infantryman - personal barriers allow one to take 2-3 direct hits without consequence, even if the weapons are powerful enough to devastate the environment. The relative uselessness of cover (a 12d(5) burn laser rifle can easily punch through 50 cm of concrete) places emphasis on mobility and stealth.
• Mobility & Stealth: Due to advanced adaptive camouflage, long-range spotting is almost impossible, further cementing the short-ranged nature of modern firefights. In such circumstances, lightning reflexes and agility are very valuable, leading to the use of unarmored exoskeletons to improve an infantryman's speed, and cognitive upgrades that shorten response time.

The Main Issue: The personal barriers. Our first idea was for them to function like video-game rechargeable shields. Their Achilles' heel would be that they can be bypassed by melee attacks, a necessary precaution to allow the wearer to breathe and move about without deflecting off the ground. While researching the Holtzman shields from Dune for inspiration, I stumbled upon a "5 to 9 centimetres per second" factoid about the maximum speed that could pass through them. That's about 0.32 km/h, or 15 times slower than the human walking speed; it matches the fight depicted in the old Lynch movie. While it would indeed be very difficult to deal an effective knife blow at such a snail's pace, it also makes me wonder how they even manage to walk! Wouldn't every step cause them to bounce off from the floor? And even a casual stroll would suffocate them, as the air around them would move at a relative velocity of more than 0.32 km/h.

So, I decided my barriers would have a more plausible speed limit. Which one would you set? What is high enough not to interfere with one's movement, but low enough to block most attacks? How would you go about duelling with such defences and attacks? My search-fu came up with some suggestions from these forums: a Slow Attack technique, using the "pulling punches" rule, only making telegraphic attacks, and an interesting (but slightly killjoy) idea of a contact-detonation explosive on the tip of pole.

Benchmarks for human speeds (warning; some have shaky or contradictory sources):

• World's fastest runner - 44.72 km/h
• World's fastest kick - 100 km/h
• World's fastest punch - 70 km/h
• katana swing (Mythbusters S4E19) - 77 km/h
• World's fastest golf club swing - 238 km/h
• Tip of a swung longsword - 300 km/h?

[Icelander]

You're going to have to do something about the fact that anything which allows a decent punch or kick through is also going to allow lobbing a grenade through. Which is considerably more effective than stabbing someone, if you're on a battlefield and not trying to avoid having anyone know that there is a fight on.

[vicky_molokh]

Originally Posted by Icelander

You're going to have to do something about the fact that anything which allows a decent punch or kick through is also going to allow lobbing a grenade through. Which is considerably more effective than stabbing someone, if you're on a battlefield and not trying to avoid having anyone know that there is a fight on.

Wouldn't the grenade just bounce off the torso, only for its subsequent nearby explosion be stopped by the shield?

[Walrus]

Originally Posted by vicky_molokh

Wouldn't the grenade just bounce off the torso, only for its subsequent nearby explosion be stopped by the shield?

Maybe it has some sort of contact trigger since it's valuable tactics in that world?

[johndallman]

Given nanofabrication, the society needs matter, which it presumably gets from moons, asteroid belts and other shallow gravity wells, and energy. Is that fusion, solar, or what? Can a primary power source be small enough to carry? Without that, simply running an opponent's power supply down seems to be a good tactic.

What is there in the way of computing, AI and robots?

Presumably there are social controls on using large enough explosions to just kill someone through the DR of a personal barrier? Using a lot of small explosions or a machine gun to chew through the ablative DR looks very possible at present.

[Polydamas]

Originally Posted by Icelander

You're going to have to do something about the fact that anything which allows a decent punch or kick through is also going to allow lobbing a grenade through. Which is considerably more effective than stabbing someone, if you're on a battlefield and not trying to avoid having anyone know that there is a fight on.

A grenade which could only injure one person on a direct hit would not be very effective at disabling opponents. Especially if one could protect oneself completely by moving 1 m away from where it landed.

[Icelander]

Originally Posted by vicky_molokh

Wouldn't the grenade just bounce off the torso, only for its subsequent nearby explosion be stopped by the shield?

Detonate them by a contact or remote fuze. At TL11, the options for controlling exactly when a grenade explodes ought to be fairly extensive.

[Langy]

I'd probably go with 100 km/hr or so if you want it to be all about speed, but really how I'd handle it is probably kinetic energy. Allow things with relatively low kinetic energy through, and only start stopping it at pistol or rifle levels.

[Icelander]

Originally Posted by Polydamas

A grenade which could only injure one person on a direct hit would not be very effective at disabling opponents. Especially if one could protect oneself completely by moving 1 m away from where it landed.

It's a lot more effective than using knives.

[vicky_molokh]

Originally Posted by Icelander

Detonate them by a contact or remote fuze. At TL11, the options for controlling exactly when a grenade explodes ought to be fairly extensive.

Well, that still requires a direct hit and/or the ability of grenades to figure if they just hit a target or a random wall. Definitely better than knives. Definitely more fiddly than a gun.