Today's relatively pedestrian (but still expensive) Missile Defence efforts are sometimes called "Son of Star Wars". Today happens to be the thirtieth anniversary of the original Star Wars movie; possibly an omen for the imminent Mid-course Interceptor test.
The Mid-Course Interceptor is the main weapon in the second layer of protection, where ICBM warheads which have survived the boost phase are picked off during their ballistic arc through space. In addition to land-based interceptors, however, the MDA also plans to make use of US Navy Aegis cruisers and destroyers here. These ships are being progressively equipped with more capable SM-3 Standard missiles, which can hit shorter-range, low-flying missiles. The warships' radars will also assist in tracking targets.
Mid-course defence against ICBM warheads travelling through space needs to be done well away from the United States; that's why the Pentagon wants to site gear in Eastern Europe, and why it's glad to have the Fylingdales radar station in the UK. Radars and interceptors in Europe would be vital to defend against an ICBM launch from Iran (just to pluck a name from the air).
The Iranians don't yet have any nukes, though the latest estimate from the UN is that they could be tooled up in three to eight years. The Islamic Republic is also collaborating closely with North Korea on missile and rocket technology. North Korea is known to have an ICBM design which could hit the USA either from Iran or across the Pacific. However, this missile - the Taepodong-2 - blew up 40 seconds off the pad when it was tested last year.
In order to guard the Pacific flank, the US is negotiating with Australia and Japan: a basic agreement was confirmed this week.
If things don't go well for the Americans in a missile attack of the future, warheads may survive boost and spaceflight to descend and re-enter the Earth's atmosphere above the USA. At this point, a final chance exists to pick them off before impact using smaller interceptor missiles such as the Terminal High Altitude Area Defence (THAAD) system. THAAD carried out "operationally realistic" tests at Kauai in the Pacific in January and April, but these were against Scud-type theatre range targets rather than simulated ICBMs. THAAD is portable and can be deployed overseas to protect US forces or friendly nations; Aegis ships with SM-3 can do this too.
The MDA has all kinds of other wacky kit apart from its radars, interceptor missiles and jumbo-jet laser cannons. There are microsatellites, sea-going radar platforms and a 500-foot solar-powered robot blimp.
This amazing armoury of gear is causing some disquiet in Beijing and Moscow. Russia's President Putin has just this week slammed the proposed European deployments as "totally counterproductive", and the Chinese authorities have made their opposition manifest, suggesting that America is "impairing the strategic stability among big powers...negatively effecting the internal stability of the relevant nations...and...increasing the offensive nature of the US foreign policy."
Russian missile forces could probably overwhelm the MDA shield as now envisaged - it was never intended to resist strikes involving thousands of warheads. President Putin said last year that "our strategic deterrent forces should be able to guarantee the neutralisation of any potential aggressor, no matter what modern weapons systems he possesses". And as things stand, they probably can.
China, however, has a much smaller and less capable arsenal, and could well feel that a working US missile-defence programme had robbed it of its strategic position. The American military sees China as a more probable adversary than Russia nowadays, so it's plausible that the MDA wants to build a shield that could resist the People's Republic as well as North Korea or Iran.
Some Washington critics of Missile Defence contend that China isn't a likely enemy and that the MDA doesn't, therefore, need everything that it's asking for.
In particular, the Space Tracking and Surveillance System - a satellite constellation which the MDA wants to augment its surface radars - has faced opposition on Capitol Hill, despite Pentagon bigwigs' support for it.
Much of the news about deadly missile threats menacing the USA in recent weeks has emanated from within the Pentagon and the US intelligence community. Examples include the launch of a new Korean missile from an Iranian site, and the revelations in today's Financial Times that the Pentagon had been "surprised" by the "quickened pace" of the Chinese push to develop credible submarine-launched nukes.
These leaks could have more to do with budget battles being waged in Washington than with future orbital or upper-atmosphere combat. ®