Mechs vs Tanks

Sci-fi and anime loves mechs, but there's a widespread belief that mechs are just absolute trash idea, and tanks are superior in every way.

Here's example of such claims: part one, part two.

This is completely wrong.

Cube Square Law

Part of the problem is conflating the idea of a mech, with the idea of a giant mech. Mechs can come in all sizes.

And in fact military is already actively researching mechs! Just among many such projects - DARPA's TALOS project is an bulletproof, weaponized, AI-enhanced exoskeleton - basically a small mech.

It might take a few decades before such mechs become deployed by actual armed forced, but it's ridiculous to call something crazy when prototypes have been in development for years now.

Weapons vs Armor

History of warfare is an endless race between weapons and armor, with either being on top at different times.

During the Middle Ages, armor was king, and a fully armored knight was nearly invulnerable to whatever peasants could throw at them. But just a few short centuries later, no amount of armor humanly possible to carry could stop a musket bullet, so weapons were king, and armor got abandoned completely. Ironically the Peak Armor era was time when armor was already on verge of obsolescence, but it was easier to double down on old strategy instead of rethinking everything.

When tanks were introduced, a big reason they were quite successful was protection offered by their armor. Common infantry weapons just couldn't do anything to them, but of course that didn't last long.

As weapons got better, tank armor got heavier, and fast. First tanks to see combat in World War I had 12mm of armor.

By end of World War II, armor reached 250mm. To still be functional, it had to have far more compact shape.

It wasn't really possible to keep increasing the weight, and modern tanks aren't really much heavier than WW2 tanks, but using advanced materials to increase protection, the race between weapons and armor continued for a while longer.

Passive vs Active Protection

Right now it looks like the weapons are getting ahead. Armor is by no means useless, but in 2006 Lebanon War, Iranian anti-tank guided missiles were able to penetrate the most modern tanks just fine.

Weapons keep getting better, and it doesn't seem like armor has much space left to improve.

All militaries can see that, and they're equipping their tanks and other vehicles with active protection systems, which attempt to shoot down incoming missiles before they hit.

It's tempting to think that active protection is just another phase in evolution of tanks, but that's just wrong.

Tanks are the form they are because that's the only way to have thick armor while keeping weight reasonable.

Active protection has no such limitations. It doesn't matter if you install it on a tank, a light vehicle, or for that matter on an exoskeleton.

If active protection ends up being the winner, then mechs work just as well as tanks. And then liberated from just one form factor, we'll likely see a wide variety of different shapes of military vehicles - some might still look like current tanks, but others might very well look like mechs of various sizes, or something completely different.

And if active protection ends up being a big loser? Then giant mechs make no sense, but then neither do tanks.

Power Considerations

Another issues with mechs of all sizes is difficulty providing enough power and energy storage for them. Right now tanks are just more efficient, and mechs and exoskeletons are not very practical.

Fortunately for mechs, battery and engine technology is improving at very rapid pace, so it's entirely reasonable to expect this issue will go away soon.

There are even ways to recharge from air or space without any physical contact.

Future Prediction

In our world, it's very likely that exoskeletons will become widespread over next few decades, just like drones before them.

It's also very likely that active protection systems will increasingly become main protection. This will likely mean future tanks becoming lighter, as all that heavy armor just won't matter all that much. Wider variety of (mostly autonomous) military vehicles will come into widespread use, with very few relying on heavy armor, and most on active protection, stealth, or just being really cheap and expendable like most types of current drones.

Giant mechs? That's more farfetched for now, but if we have this discussion in a few decades, at time when most armies consist of exoskeleton-clad infantry supported by drone swarms, this really won't sound that far outside realm of possibility.

So if even our world is on verge of having mechs, it's just ridiculous to think there's no place for them in any sci-fi world, where technologies might have developed along different lines, and trade-offs are different?

The "tanks are always superior" crowd is going to sound just as ridiculous as believers in eternal superiority of heavily armored cavalry were a few centuries ago.