Missile Defense Capability

[EyeKhan]

I saw the article below and wondered if anyone here knows much about the current state of anti-ballistic missile defense technology. I remember the patriot missile system from way back and how early reports claimed it was shooting down Iraq's SCUD missiles, but later analysis showed it never even scored a hit. Is the below more about propaganda, or do we actually have a capable ballistic missile defense system now?

U.S. Sends First Parts Of THAAD Missile Defense System To South Korea

Citing the threat posed by North Korean missiles, the U.S. military has sent the first elements of its Terminal High Altitude Area Defense (THAAD) system to South Korea. China has opposed the move, which has also drawn mixed reactions in South Korea.

The shipment landed in the night of March 6, with a C-17 cargo aircraft unloading two large mobile launchers on the tarmac at Yongsan Garrison in Seoul. The plan to install a THAAD system on the Korean peninsula was laid out by the U.S. and South Korea last summer.

"China says that its main concern is that the system's radar could be used to spy on China's military, and the missiles could possibly counter China's nuclear deterrent," NPR's Anthony Kuhn reports from Beijing.

The U.S. is calling the system's deployment a defensive measure, saying that it is "aimed solely at" defending against missiles from North Korea. Last month, North Korea test-fired a "medium- or intermediate-range" missile, and on Sunday, it fired four missiles — one of which is believed to have flown about 620 miles before it splashed into the Sea of Japan.

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http://www.npr.org/sections/thetwo-w..._campaign=news

[wiggin]

This is a very complicated question. First, a brief overview:

In the first Gulf War, the US military did indeed field Patriot missile batteries as a measure to intercept Iraqi Scuds that were launched at both Israel and coalition forces in Saudi Arabia et al. The concern was that these Scuds would be carrying nonconventional warheads (particularly chemical weapons), so these were high value intercepts. Unfortunately, the system at the time performed quite poorly - there were a lot of near misses that were incorrectly scored as hits (often because this version of the Patriot, the PAC-2, had an explosive warhead which did detonate near targets but was unable to destroy them). There are a lot of complexities and controversy here, but fundamentally it appears that the PAC-2 system at the time was not really a good fit for an intermediate range ballistic missile defense system. That is unsurprising that it began life (and continues to be) a pretty good antiaircraft platform but not originally intended as a missile defense platform.

Some limitations of the Patriot missiles - even their much-upgrade variants now in service with Western and allied militaries - is that their defense footprint is pretty small (you need a lot of batteries to cover a region) and they are quite expensive to launch, so are only useful against high value threats like unconventional warheads.

THAAD is a system that works a bit differently and has about an additional 2 decades of development from the PAC-2 systems fielded in 1991. It's designed to intercept short to medium range ballistic missile threats and can cover a relatively large 'theater' with a single system (though to cover all of SK you'd need several systems linked together). It works by hit-to-kill technology (e.g. it actually hits the target to intercept rather than getting close and blowing up) and sports a much better radar and targeting system than that used in 1991 for the Patriots. It, like the Patriot, targets missiles during the terminal phase of the trajectory (rather than an exoatmospheric intercept or a boost phase intercept); hard to do since the missile is moving at its fastest, but easier to do with a relatively short range interceptor. In testing, it has performed quite well after some initial teething problems in the late 90s, but it has never been tested in combat. Some limitations: also quite expensive per intercept, not useful against very short range attacks, and has unknown combat efficacy.

There are also other US systems of similar capability that have been fielded in recent years that also seem to work much better than early PAC-2 days, even if we don't know how they'll function in combat. In naval (and not land based) form, there is the Aegis BMD system which has a pretty good testing record using both SM-2 and SM-3 missiles and pretty powerful radar/targeting systems. The US-funded and Israel-designed/fielded Arrow-2 has similar performance characteristics in testing, and the Arrow-3 uses a better interceptor and seeker and may involve the capability for a limited exoatmospheric intercept. The more pie-in-the-sky systems are aimed at true ICBMs and typically involve exoatmospheric intercepts; like the Ground Based Mid-Course defense system that has been plagued with cost overruns and test failures. Theater based systems against shortish range threats are fielded and seem to be at least moderately capable.

The real question is whether THAAD would be useful in a confrontation with NK (notably, SK already fields upgraded Patriot batteries). First, they are useless against large numbers of conventional projectiles because of cost and target discrimination issues; this means that if a nuke-tipped missile was slipped in with a conventional swarm, the system likely couldn't get an intercept. Second, they are useless against shorter range threats like artillery and low trajectory threats, of which the NK military has a truly ridiculous number aimed at Seoul and environs. So in a real shooting war with NK, I wouldn't count on them being particularly useful. That being said, there's a powerful radar as part of the system that could be networked with other US systems and provide early warning of launches aimed not at SK but at allies or US bases. Furthermore, the deployment of THAAD is more of a signal aimed at NK and their patron China than a meaningful military defense; it pisses off the Chinese because the radar is also aimed at them, and it pisses off NK because, well, everything pisses them off.

A more useful system for parts of SK would probably try to counter the shortest range threats that are likely the biggest threat to SK/US forces and SK civilians in a shooting war with NK. This would probably involve so-called C-RAM systems like the Phalanx CIWS or slightly larger coverage systems like Israel's Iron Dome. They might be effective against threats like short range rocket artillery, mortars, and the like, but you need to field a LOT of systems (this is really not theater level defense but point defense) and they're useless against bigger threats. It's entirely possible that some sort of C-RAM system is already deployed near high value US bases in SK; I don't know. These systems tend to be a bit cheaper per intercept and have actual combat records (some of it quite good), but are again aimed at different threats than a nuke-tipped intermediate range ballistic missile.

So, long story short: THAAD probably works reasonably well for what it was designed to do, but it probably of limited value to SK defense. Its stationing in SK has more to do with politics than anything else.

[EyeKhan]

This is a very complicated question. First, a brief overview:

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So, long story short: THAAD probably works reasonably well for what it was designed to do, but it probably of limited value to SK defense. Its stationing in SK has more to do with politics than anything else.

Thanks for the detailed response. The conclusion is what I suspected to be the case.