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Comment by sudosysgen | Hacker News Reader

Houthis use long range drones and cruise missiles which can easily be fired from the West over the Red Sea. There is no plausible situation where they simply don't point the radars that way.

There is also SBIRS and radars across Saudi Arabia. By far the likeliest scenario is that the US detected the attack and made the choice not to defend Qatar.

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The US probably was able to detect the launch, yes. But would they have assets in place to conduct an intercept in time? Different systems are meant for different targets, and physics put fairly stringent requirements on where an interceptor launcher has to be to protect a specific area. Plus you've got only a few minutes from missile launch to impact. A few minutes to figure out missiles have been launched, confirm it's not a bug or an anomaly, figure out where the target is, get that information from the person monitoring the sensors to command and control plus the missile launch crews, get authority to launch (which depending on the rules of engagement may require going high up the chain of command), get fire control radar tracking the targets (something like SBIR wouldn't be enough, the missile battery needs its own high-quality track), and then launch the interceptor. Also add that people are human beings, and that no one was expecting an eminent strike on Qatar from anyone.

Qatar has a THAAD and Patriot installation, the former assumed to be manned by the US, which can engage these threats. The latter can detect them at a much lower range.

These missiles are not especially fast given the distance they have to cover. They were in the air for 10+ minutes, more than enough time to cross check IR early warning and radar tracks.

The AN-TPY/2 radar only sees in a 90 degree arc. Given the primary threat in terms of ballistic missiles is from Iran and maybe Yemen (do the Houthis have ballistic missiles that can range Qatar?) they probably weren’t facing in that direction. I’m not sure how SBIR sensors are managed, but I’m assuming Space Force, and I don’t think there is standard automated data sharing of those findings to THAAD or Patriot batteries in the field. So you would probably be looking at someone in Space Force noticing this and sending some sort of priority alert to everyone in the area. Then the battery crews see the alert and turn their radars around, which takes a second. And then you have to think about launch angles for the missiles. If the battery was stationed a couple kilometers from the intended target, fine. But I’m willing to bet they were probably deployed further away, maybe much further away. I believe they are mostly there to protect the US base there. Quick googling estimate indicates maybe 50km, which is closer than I thought but still not close. All of this also assumes that the missile batteries were fully deployed and on ready alert too, which may not have been true.

I should clarify that it is ENTIRELY possible that you are correct. It is entirely possible the US made a choice to not intercept here. My point is that it is also entirely possible that the US didn’t make a choice. I just don’t see enough clear data to tell. I also think that, even if it was a choice, it was probably more of a split-second decision made by lower-level officers on the ground as it happened, rather than a carefully-considered decision made by national security leadership.

AN/TPY-2 has a 120 degree FoV, and CENTCOM operates them all across the ME, not just in Qatar, but also in Saudi Arabia, the UAE, and in Israel. The likelihood that none of those installations had the ALBMs in range is basically zero.

The chain of actions you're describing would have around 10-15 minutes to be executed.

The likelihood that neither THAAD nor any of the Patriot batteries were sufficiently ready to launch is also basically zero.

THAAD has an engagement range of over 100km, so the battery was undoubtedly in range; and it can cue Qatar's own Patriot batteries so they can launch the missiles; I find it hard to believe there were none in Doha.

So, this would not be a split-second decision - there was quite a bit of time given the proposed trajectory. It's very very unlikely the US didn't have the sensors to see the missiles given the intense concentration of long-range ABM radars in the region.

Is it theoretically possible the US legitimately couldn't do anything? Yes. But the odds are overwhelming that the US knew about the strike with minutes to spare before making a decision, and decided not to protect Qatar.

Your second sentence is part of the answer to your first one...

You'd need air launched ballistic missiles (which Israel used) to avoid detection by Saudi radars. The Houthis don't have those.

You'd need jets capable of operations over the Red Sea - which the Houthis don't have.

If they did have those things, they'd certainly use them to attack Israel or Riyadh, not Qatar.

ALBMs are not any harder to detect than normal ballistic missiles. You don't need jets to go over the Red Sea either, Houthi cruise missiles can operate over the Red Sea and then change course to hit their targets.

If you know where they’re launching from, you can equally detect ALBMs or ground launched ones - but given that ALBMs have mobile launch ‘pads’ with thousand+ mile ranges, they’re actually much harder to detect. Hence why we’ve just started rolling out the next gen OPIR this year..

You don't need jets to go over the Red Sea either, Houthi cruise missiles can operate over the Red Sea and then change course to hit their targets.

You do if you want ALBMs… the “A” is pretty important for that acronym.

And cruise missiles are not ballistic missiles. Cruise missiles that tracked up the Red Sea and then crossed 1,200km of Saudi Arabia while heading for Qatar would obviously be detected (and likely shot down) by US and Saudi air defenses.

The radars that Qatar has to their disposal are the same for cruise and ballistic missiles.

Due to the curvature of the earth, such a cruise missile attack would almost certainly not be detected until it got close to Qatar.

Cruise missiles fired from the Red Sea would spend nearly an hour flying over Saudi Arabia.. I didn’t say Qatar would detect them, but the US and Saudi air defenses based in Saudi Arabia would certainly.

Hence why Israel used ballistic missiles that likely reached 30+ km in altitude over Saudi air space and impacted in less than 15 minutes after launch.

They likely would not, due to the curvature of the earth. The locations of the air defenses are known, and the cruise missile fly low such that the detection range is limited to around 20km by the horizon. So they typically only get detected once they are close to their targets.

This is why cruise missiles and drones fired from Yemen routinely hit their targets in Israel, in fact that happened just yesterday.

Israel used ballistic missiles in all likelihood because those are the weapons that Qatar needs American help to intercept.

Except that Qatar's own systems also did not issue any early warnings.

The system with long range detection radars (THAAD) is operated by the US, not Qatar. Qatar's radars would not be able to detect a ballistic missile until it was already too late, as detection range for BMs is only around 100km.

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