Remind me why walking combat vehicles are not a valid combat platform?

Because they are inherently unstable.
Their motion requires a controlled fall.
The unit is immobilized if one of the “legs” is disabled.
It offers a larger target area.

Two big reasons are cost and reliability.

Is there any way that they could be practical?

Maybe after another 100–200 years of development in robot leg technology.

It is a much harder engineering problem to make a humanoid object walk, balance, get up if it falls down, etc., than it is to make a blocky object roll on wheels or tracks, or an air cushion (hovercraft) or helicopter, or even hovering jets.

And there are not many advantages, except that some young boys think they look cool, and they are more appealing to human audiences. Combat advantages are few, if any.

If you had super technology, maybe they would be good for negotiating some different types of terrain compared to other forms. However they would still be less stable, so I think you would still see better payloads and road speeds for the same investment, going with tracks and wheels.

Human-sized powered exoskeletons (powered battle armor) might be more likely to be more practical, sooner.

We have the technology more or less, but the cost vs. benefits just isn’t justifiable at the moment. Walkers wouldn’t really do anything that tanks can’t do right now, and there really isn’t a tactical advantage to using them, aside from the badass factor.

Also, if the US Military ever fielded anything like the T51-b Power Armor from the Fallout games, I’d enlist in a heartbeat.

If the US millitary had an AT-AT I suspect we would have won the war on terror.

I think one of the main problems is political fallout. This sort of weapon system would certainly not be a winner with the current hearts and minds campaign.

I don’t know to what extent the M1A1 Abrams is being used in Afghanistan, but I personally believe that on hilly terrain there is a potential that the high ground could be held by mechs, supported by mobile SAM batteries.

Has anyone seriously studied this openly?

Aside from the engineering and technical difficulties, I can’t imagine the motion sickness their poor occupants would suffer from.

@gorillapaws The US will never win the war on terror, given that it’s impossible to fight an abstract noun.

@meiosis While on a general basis I would 100% agree, I feel that an AT-AT would probably still have the capabilities necessary for destroying abstract nouns as well.

@gorillapaws An AT-AT? Why would that be helpful? Seems to me that they would have trouble turning around in city streets, and they are vulnerable to attack from the sides, rear, and below, by such weapons as ropes and logs. I’m not impressed. The fact that they use legs (the point of this question) rather than tracks seems a positive disadvantage.

@Zaku I don’t think AT-AT’s are vulnerable to ropes and logs. As far as being attacked from the sides/rear/below is fairly moot given the armor on that thing. If you’ve ever seen Saving Private Ryan then you’re probably familiar with the sticky bomb scene where they blow the treads off of a tank. Walkers would be immune to such tactics because their legs are basically solid metal.

@gorillapaws In the Star Wars films, it seems there was a definite point made that brave people with ropes and logs could cripple walkers and take them out by tripping them. Stone-age teddy bear Ewoks were able to defeat them with primitive traps using logs and vines set off by stone axes. They also seem to be susceptible to crew capture by men with powered grappling hooks, and oversized orangutans (Wookies). Moreover, the heavy armor or shields they have don’t have anything to do with them being on legs, so it’s not a reason to have your combat vehicles use legs.

@Zaku you’re mixing up the AT-ST and the AT-AT. The AT-ATs were the enormous walkers on Hoth. Their feet were big enough to completely flatten Luke’s snow speeder. The AT-STs were the ones on the Endor moon that fought the Ewoks.

I just said walkers. Sure the two-legged AT-STs were easier to take out, but the AT-AT’s were also vulnerable to tripping by cable and by a grenade up the underbelly. And, why do you suppose there were no AT-AT’s in the battle of Endor? Perhaps because it was forested, and enormous walking robots wouldn’t be terribly effective there?