Power Armor -- Power Shield?

[Tallor]

I was thinking about how shields had gone out of style due to improving armor, and in modern days are seen as plastic riot shields or heavy-duty entry shields... and I realized: What if someone with power armor carried a huge shield? Power armor is already very tough, but the shield would be a tactical option--the be-battlesuited one would wade into battle, hammer the shield into the ground, and move from there. Other, "softer" allies could use the shield as cover as they moved up from one position to another.

What do you think?

[mhd]

Wouldn't a big flat surface be pretty bad for modern projectiles and/or lasers?

[Mailanka]

Originally Posted by Tallor

I was thinking about how shields had gone out of style due to improving armor, and in modern days are seen as plastic riot shields or heavy-duty entry shields... and I realized: What if someone with power armor carried a huge shield? Power armor is already very tough, but the shield would be a tactical option--the be-battlesuited one would wade into battle, hammer the shield into the ground, and move from there. Other, "softer" allies could use the shield as cover as they moved up from one position to another.

What do you think?

If you want mobile cover, you could create mobile cover. I don't think it would look much like an actual shield, though, more like a portable barricade.

Would you like actual shields for actual power suits so you can have sci-fi knights with sci-fi shields and sci-fi armor? Then go for it, and don't worry overly much about the physics of it. As long as it feels plausible, it'll be okay.

[Varyon]

Originally Posted by mhd

Wouldn't a big flat surface be pretty bad for modern projectiles and/or lasers?

Shields don't have to be flat, they can be sloped/fluted just like armor.

As for OP, yes, mobile infantry could certainly carry heavy pavises for portable cover for the softer troops. Note, however, that they'd be giving up no small amount of their own carrying capacity to do so, and they may be better served by having thicker armor, heavier weapons, more ammunition, and so forth, rather than lugging around that giant pavise.

Historically, the advantage of a shield is that you can effectively cover more of your body with armor for less weight, as you can move the armor around. It also had other advantages, of course - you could actually knock an attack away rather than just absorbing it, the arm holding the shield functions as a spring to help absorb some of the blow (effectively increasing the DR of the shield, albeit slightly), the shield can be an effective weapon in its own right, and of course a shield (even a strapped-on shield) is much easier to drop than worn armor when you need to move quickly (namely, run away). With the exception of being able to drop it, none of these really apply with firearms in the mix - bullets are just too fast to intercept by more than just chance, and the inability to use one arm for ranged combat (restricting yourself to one-handed firearms) typically more than offsets the small advantage of being able to move your armor coverage around while preparing for an attack.

For pavises, the big thing (aside from weight, but the power armor helps with that) in modern and post-modern combat that offsets their benefit is explosives. HEAT/HEMP rounds are going to punch right through nearly any portable pavise and hit those hiding behind it. You could have the pavise be reactive armor (probably EMA - see later for the issue with explosive reactive armor), but the immobile nature of cover makes the multi-hit problems of reactive armor more pronounced. A pavise isn't going to be very tall and isn't going to have a roof (otherwise it's too awkward to really carry around), so airburst explosives will be a fairly reliable counter. Unless you're dealing with an incredibly heavy pavise and/or one with some really solid methods of anchoring itself (and rather resilient ground it's anchoring itself into), a decent explosion has a pretty good chance of knocking it down, at least removing it from play as cover and possibly crushing the unfortunate infantrymen hiding behind it. Also, when in an environment with natural cover, the big advantage of using such is concealment rather than proper cover - it's hard to figure out where the targets are when there's a lot of cover they could be hiding behind. A pavise is going to be a big red "Soldiers hiding here!" sign, meaning the enemy is going to bombard the thing with the options I listed above.

Note this all assumes you're up against an enemy who is comparable to you. Against less advanced forces, a pavise might be properly useful for your lightly-armored infantry to hide behind - but at that point, you could probably just leave them back at base and load your mobile infantry up with more gear in place of those pavises and have them take care of the enemy.

[Anaraxes]

Originally Posted by Varyon

Shields don't have to be flat, they can be sloped/fluted just like armor.

Being flat is also not so disadvantageous as the post seems to presume. Look at modern armored vehicles, including tanks. Planar surfaces all over. The point there is that it's unlikely that you'll hit them at a perfect 90 degree angle, and sloped armor is effectively thicker. Or look at the WW II Sherman tank. The early models had a distinctly curved hull, while later ones were planar, though the same general shape. This was because the early ones were cast, while the later ones were made out of rolled plate. This had a lot more to do with available steel foundries in the US than any ideal of armor design. For that matter, you can find examples of historical shields that are either planar or non-planar.

I agree that the reason shields went out of fashion is simply that you can't move them to intercept bullets. Therefore, they're no longer shields, but instead cover (a pavise) or armor (DR, not Block), in which case your choice of location for extra armor is probably not the off hand. The fact that the main weapons became two-handed and ranged is also likely significant. Shield-and-pistol armed troops won't deal well with riflemen.

[RyanW]

Originally Posted by Anaraxes

I agree that the reason shields went out of fashion is simply that you can't move them to intercept bullets. Therefore, they're no longer shields, but instead cover (a pavise) or armor (DR, not Block), in which case your choice of location for extra armor is probably not the off hand. The fact that the main weapons became two-handed and ranged is also likely significant. Shield-and-pistol armed troops won't deal well with riflemen.

Even when firearms were only a small factor on the battlefield, heavy armor was making two-handed weapons much more important. Once firearms could reliably penetrate any practical armor, but before the bayonet allowed for all-gun armies, it looks like shields may have actually made a small resurgence (with the Scots, for example).

[Donny Brook]

The variety of threats on the modern battlefield that avoid a shield entirely make it a device of questionable utility. The APC is the modern shield.

To restore the shield to the battlefield you need setting elements that make it sensible. E.G. Say that force screens only manifest in a disc shape and they need at least the level of energy of a battlesuit reactor.

[Railstar]

The main issue I see is that any weaponry capable of penetrating Power Armour will also be capable of penetrating Power Shields. Now you could argue that penetrating Power Shield + Power Armour would be more difficult, although in that case why not just make Power Armour with an additional layer?

So first issue is that the Power Shield needs to do something that the Power Armour does not; so you could have a reflective shield for dealing with lasers, but if the shield is not bulletproof (or whatever the standard weapon is) it will get chewed up quickly on a battlefield. But if you can make it both bulletproof and reflective, why not just do that with the battlesuit?

Portable barricades like you mention might be plausible… but I could see them having wheels or tracks or some other form of self-locomotion.

Energy field generators would seem the most viable way to go, perhaps to activate while moving, then deactivated once in position (if they also stop you from shooting out).

[Varyon]

Originally Posted by Railstar

The main issue I see is that any weaponry capable of penetrating Power Armour will also be capable of penetrating Power Shields. Now you could argue that penetrating Power Shield + Power Armour would be more difficult, although in that case why not just make Power Armour with an additional layer?

While I generally agree that shields are unlikely to see much use from power armored troopers, there are reasons why you might opt for a shield rather than thicker armor. One is weight - if you can reliably anticipate where the target is going to attack, a single shield will weigh less than putting heavier armor on every single hit location. Another is volume - if you're already at (or very near) the limit of how thick you can make your armor before it starts seriously limiting mobility (due to getting in the way), strapping on a thick shield can give you more DR without causing this problem (and without requiring you to redesign the armor to increase the character's effective SM, slowly edging toward leaving the realm of Power Armor and becoming a Mecha).

Originally Posted by Railstar

So first issue is that the Power Shield needs to do something that the Power Armour does not; so you could have a reflective shield for dealing with lasers, but if the shield is not bulletproof (or whatever the standard weapon is) it will get chewed up quickly on a battlefield. But if you can make it both bulletproof and reflective, why not just do that with the battlesuit?

The web serial Symbiote (which I haven't finished reading yet, so no spoilers please) had diamond shields that the main character could use to reliably deflect (and reflect) lasers, and the mobility of a shield was very useful in redirecting the lasers where the character needed, but he had a combination of ETS, high levels of ATR, and a hyper-advanced AI running calculations to determine exactly how to position the shields for optimal effect, so that's an option of somewhat limited use.

Thinking a bit further on the topic, it occurs to me that shields might be more useful against HEAT rounds than mere power armor. First off, simply forcing the round to detonate at some standoff distance (there's a sizable gap of air between the shield and the armor) can reduce their ability to penetrate armor. More importantly, however, a shield is probably a better surface for reactive armor technology than a suit of armor. For electric reactive armor, you don't need to worry about the volume-inefficiency of making the armor into a giant capacitor (as thickness is much less of an issue for shields). For explosive reactive armor, maximizing the distance between your body and the explosives is a good idea. The bulging and bending of non-energetic reactive armor doesn't run the risk of making you lose mobility when it's constrained in a shield. Best of all, when the reactive nature is spent, it's a lot easier to just drop the shield to save on weight and then pick up a fresh one when you have the chance than it likely would be to remove the spent remnants of the old reactive armor and get new panels installed on your armor.

As noted upthread (and a bit in your post), superscience can also make shields more viable. If the physics of force screens make them usable for shields but not so much for armor (or perhaps they simply work better for shields and/or are cheaper to make into shields), you'll see shields make a return. In the Halo series, for example, Jackals had some very useful shields that could absorb a bit more punishment from energy weapons and explosives than the conformal shields (basically, armor) of typical Elites, and also had the advantage of outright ignoring physical projectiles (they just deflect off). There are also larger versions that are used as deployed cover and give even better protection. The Jackal shields had notches in them to allow them to use their weapons while hiding behind the shields, and while the larger versions lacked anything like that, I'd imagine some sort of gun port could be arranged (bonus - you only need holes for the weapons themselves, as the shields are translucent).

[The Colonel]

How about a dirty great block of shear-hardening foam? Low mass, ballistic resistant and ablative against explosive and/or directed energy weapons.
That might make a suitable pavaise or mantlet for the power armour era.