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human
[Pacific Rim] More practical alternatives to the Jaegers

Why did the world governments see giant monsters coming out of the see and say "Giant robot"

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I get the plasma shots.

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But why didn't they just use plasma turrets around the city.

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What about nuclear options do those work.

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Why not use satellites that would just cook the monsters from space.
gpt
The short version is that they used Jaegers because Jaegers worked.

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For the long version, let's run through your suggestions in no particular order:

They actually *did* use nuclear weapons; in fact, the very first kaiju (Trespasser) was killed in Oakland, CA, USA by three nuclear missiles. Nukes are pretty bad options, though, strictly weapon-of-last-resort - they're horribly messy. Sure, you kill the kaiju, but you also destroy and irradiate everything around it, and everything downwind of the blast. It works, but badly.

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Plasma turrets around the city would require a *lot* of plasma turrets, around every population center, enormous energy infrastructure, and some way to keep the kaiju away and targetable until the turrets could do the job. And the moment you lose a few turrets, your defenses are wide open and the kaiju can just waltz on through. This isn't an awful design, and you could protect a few key locations like this, but it doesn't scale well and it's extremely inflexible.

Worse, plasma turrets are only usable if the kaiju comes near the city. You don't want the kaiju to come near the city, they're toxic. Sometimes you'll *have* to fight them there, but if possible you want to kill the kaiju as far away from a city as you can.

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A satellite solution would require even more infrastructure than the plasma turrets. You can't just have one - you'd have to have a whole big network of them, all spread out across the globe, all engineered to be powerful enough to fire down into Earth's atmosphere and still have enough energy left to cook a kaiju. And you'd need to maintain them. And if you ever need to adapt or improve them, you'd have to be sending up new space missions. And kaiju aren't going to just stand there and be hit - you probably can't cook them while they're underwater, and on land you'll be trying to hit a relatively small, fast-moving target from a long, long, long way away. Maybe you could do this with infinite resources and a lot of space-based infrastructure, but it isn't practical.

(If you knew where the kaiju came from, and it wasn't protected by a whole lot of energy-dissipating water, you could maybe position one over the breach and snipe kaiju as they arrive - but that's not really an option for how things played out.)

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So let's re-examine our problem, here, and our needs: We have big, combat-ready monsters showing up at initially unpredictable times, in unpredictable locations, on unpredictable terrain. We can't build a wall around the whole world, but we need to kill these things before they can do too much damage, and ideally before they get too close to us.

We need war machines that can respond and deploy quickly, handle all kinds of battlefields, armed and armored to the teeth. We need to pilot them *extremely* well to keep up with the likes of the kaiju, and since each kaiju is different we need to be ready for the unknown. We need enough weapons to act as a rapid-response team, but a small enough number to be maintainable and upgradeable as tech becomes available and our understanding of kaiju grows.

We need super-tanks. That's really all a jaeger is - a manageably big all-terrain armored combat platform. Since we have the technology to pilot them in part by human brain, to make them more responsive and effective in the field, it's easiest to make them also physically resemble people so that the brain can make better sense of the input and output. So: big, armored, heavily-armed human-shaped robots.

The details, of course, are up to whoever makes the things - their priorities, their resources, their pilots, their tests & upgrades. But the basic idea, the fundamental platform, was tried, worked, and rolled out as a solution - short term or long term, depending on who you asked, but a solution none the less.