A shot in the dark?
Recent reports that North Korea might be preparing to launch a long-range missile in the direction of the United States have refocused international attention on efforts by the US and other countries to develop a system for destroying incoming ballistic missiles.
There have been signs that Pyongyang was preparing to launch an updated Taepodong-2 with an estimated range of up to 6,000km - far enough to hit Alaska and a small portion of the western US homeland. In response, the Bush administration put its ballistic missile defence system on alert.
But it is an open question whether the system could intercept and destroy an intercontinental Taepodong-2. Unless US officials thought the missile was armed, it is very unlikely that they would even try to shoot it down.
Still, Tokyo and Washington said this week they had agreed to deploy advanced Patriot interceptor missiles by the end of this year at US bases in Japan for the first time. Tokyo already has permission from Washington to produce the American-designed Patriot Advanced Capability-3 (PAC-3) surface-to-air missiles in Japan, and install them at Japanese military bases starting this year.
The US and Japan have also sent several of their Aegis-class warships into international waters off North Korea to detect and track any Taepodong-2 launch. Two US navy cruisers have been armed with the Standard Missile-3 (SM-3). However, they are not due to be ready for use until late this year.
The US military says it has shot down incoming test missiles with the SM-3 in seven out of eight attempts. The latest successful intercept of a dummy warhead was last week off Hawaii. Missiles that North Korea has previously tested can reach all parts of Japan within 15 minutes of launching. The PAC-3 batteries based on land and the SM-3 missiles at sea are designed to hit and destroy short-range and medium-range missiles, but not intercontinental ballistic missiles like the Taepodong-2. The US plans to give the Aegis missile defence system that capability in future.
For the moment, US protection against a one-off, or limited long-range missile attack, rests on six interceptor rockets based in silos in Alaska and another two in California. Ten more interceptors are planned for Alaska by the end of this year. They would be fired at an incoming intercontinental ballistic missile while it was in outer space, in the middle of its trajectory.
However, hitting a warhead travelling at more than 24,000km/h with an interceptor going more than 11,000km/h is an enormous technical challenge. So far, the US has managed only five hits in 10 tries. The last successful test was in 2002, although Pentagon officials say the problems that plagued more recent tests have been resolved. The Bush administration is spending up to US$9 billion a year to improve its missile defences.
The next advance the US hopes to make is to use modified Boeing 747 Jumbo jets, armed with powerful laser guns and sophisticated sensors and tracking devices, to destroy long-range rogue missiles anywhere in the world within the first five minutes of their flight.
But these airborne lasers will not be operational for at least another three years, leaving the US potentially vulnerable to its two 'axis-of-evil' enemies, Iran and North Korea, who have been co-operating to develop a ballistic missile strike force.
Michael Richardson is a visiting senior research fellow at the Institute of Southeast Asian Studies. This is a personal comment