Tuesday, November 08, 2005

More on Ballistic Missile Defense



UPDATE: An excerpt of the Ground-Based Midcourse Defense (GMD) article published on eDefense Online can be read here.


In a briefing conducted for invited members of the press and defense industry analysts in mid October, Raytheon officials said they were "highly confident" that the US ballistic missile defense system as currently deployed would be able to defeat an intercontinental ballistic missile (ICBM) attack from North Korea. This is a historic development with far-reaching implications for US national security policy. We are going to be covering it extensively at Situational Awareness (scroll down a bit).

Let's be clear, even if the system works as advertised this is a very rudimentary capability that would be effective against a very specific threat under a limited set of circumstances. However, given that North Korea is a high-profile potential enemy with only a very limited ICBM attack capability, the development is important in the near term as it counters a means of leverage that nation may have in its relations with the United States. It eliminates whatever certainly exists in the minds of North Korean and US leaders that a North Korean ICBM attack would be successful.

First of all, what is the US anti-ICBM capability as it exists today? In short, it is the so-called Ground-Based Midcourse Defense (GMD) system (prime contractor: Boeing) based on missile interceptors deployed at Ft. Greely, Alaska, and Vandenberg Air Force Base, California, and their associated sensors and battle management systems. As of this writing, there are nine Ground-Based Interceptor rockets deployed at Ft. Greely and two at Vandenberg. The interceptors rely on a chain of early warning radars and space sensors. The first line of detection is made up of infrared launch-detection sensors on satellites developed during the Cold War under the Defense Support Program (DSP). The satellites in geosynchronous orbit are cable of detecting ballistic missile launch plumes. The second line of detection is composed of Ticonderoga-class cruiser and Arleigh Burke-class destroyers equipped with AN/SPY-1 series radars of the Aegis combat system that would track enemy ballistic missiles during their boost-phase ascents. There are currently up to two Aegis cruisers and ten Aegis destroyers acting as radar pickets in waters near North Korea. The third and main line of detection is made up of existing early ground-based warning radars modified for missile defense purposes that would track warheads and decoys during their suborbital midcourse flights. The key installation is the AN/FPS-108 Cobra Dane L-band phased-array radar at Eareckson Air Station on Shemya Island, Alaska. Battle management of a ballistic missile intercept would be handled by the GMD Fire Control Node at Ft. Greely.

The payload of the Ground Based Interceptor is the Raytheon Exoatmospheric Kill Vehicle (EKV), which essentially is a maneuvering spacecraft with an electro-optical (EO) sensor and a command link to the ground. The Ground Based Interceptor is launched into the path of the incoming ICBM as determined from tracking data from the various ground and space-based sensors. Upon separation, the EKV receives updated course correction from the GMD Fire Control Node. During the midcourse phase of its flight, an ICBM will release its reentry vehicles and perhaps a number of decoys. The latter are typically radar decoys that mimic the radar signature of a warhead or IR decoys that mimic the IR signature of a warhead. By combining data from ground based radars and the EKV's onboard EO sensor, the wheat will be separated from the chaff and the EKV will be instructed to engage a warhead target. The interception is a "hit-to-kill" event wherein the EKV impacts the warhead, destroying it utterly through kinetic energy. Battle management doctrine would determine how many Ground Based Interceptors would be launched at a given inbound ICBM to ensure the destruction of its warhead(s). Such battle docrine is highly classified, but it might be assumed that at least two interceptors would likely be launched at a missile suspected of having a single reentry vehicle warhead.

If North Korea launched a ballistic missile at the US right now, this is the defense system that would mobilize against it. Over time, various elements of the GMD system are being modernized. Notably, the Sea-Based X-Band Radar (SBX) is on its way into the Pacific to take over for Cobra Dane as the primary mid-course sensor. The SBX is an impressive ocean-going structure that any James Bond villain would be proud to call home. It is also worth noting that the PAVE PAWS radar at Beale Air Force Base, California, and the Ballistic Missile Early Warning System (BMEWS) radar at Fylingdales, UK, are being modified to serve as GMD sensors. The US is preparing to launch new satellites and deploy new air-transportable ground-based radars to improve coverage of enemy launch sites. But for now, the system described above is what the US has in hand to defeat an ICBM attack.

And what of the threat? As it stands, North Korea does not have an ICBM that could reach the mainland United States. It does have classes of intermediate-range ballistic missiles (IRBMs) -- the Taepo Dong series -- upon which an ICBM could be developed. The GMD system is not intended nor would it be effective in engaging IRBMs or shorter-range theater and tactical ballistic missiles, of which North Korea is well supplied. This is a different threat, and different means of countering are being developed. Those programs are outside of this discussion.

Starting in 2003, there were reports about the so-called Taepo Dong-X ICBM that North Korea was on the verge of deploying. This missile was regarded as being either a further development of the Taepo Dong-2 or based on the Russian SS-N-6 submarine-launched ballistic missile or perhaps even the product of an integration of these two missile types. Estimates of its effective range varied wildly, with some unidentified Bush Administration officials reported as saying the missile could strike virtually anywhere in the continental US. There is no way of knowing, because a Taepo Dong-X has not been unveiled, much less tested. In fact, the Taepo Dong-2 is itself untested. While it would be imprudent to dismiss the threat posed by such a missile for the present, it also must be considered unlikely that the North Koreans would risk such a monumental decision as striking the US with an unproven system.

So was the high confidence expressed by Raytheon officials in the ability of the GMD system to defeat a North Korean ICBM based on the fact that no such threat exists? That would be a very cynical observation. More likely it is based on the assumption that the GMD capability in hand could be developed and modernized to stay ahead of any ICBM system the North Koreans could deploy. Thus, North Korea would not be able to strike the US with the ICBM systems it is currently developing. Consider, then, that the GMD is designed to inform North Korea and perhaps Iran or any other would-be-wielder of ICBMs (as opposed to current wielders such as Russia and China) that the US homeland will forever be beyond their ability to strike with such weapons.

Of course, the GMD doesn't speak to the threats posed by nuclear weapons delivered by shorter-range ballistic missiles launched from sea-based platforms such as Q-ships or submarines, or by long-range cruise missiles, or those smuggled in by container ship or other means. Moreover, there are many critics of GMD who question the effectiveness of such a system on technical grounds. Others oppose the system on geopolitical grounds. Still others question the cost-effectiveness of GMD in light of other options, such as pre-emptive strike. These, my friends, are topics for another day. There's a lot to discuss, so stay tuned.

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