@CampaignReboot, making a good point as always, earlier linked to this CNN article which bemoans the state of the United States’ missile defence programme after the failure of a Ground-Based Interceptor test.

Just to reinforce his point, let’s look at how insanely difficult a task a Ground-Based Interceptor (GBI) missile has.

An ICBM launch is first detected by detectors, usually radar, at sea, on land, and in space. All this data must be fed back to the missile base and analysed by a computer within a few minutes.

A GBI attempts to intercept it while it’s in its “midcourse” phase, which generally lasts for around 20 minutes – but it’s not as if the GBI turns around and tries again if it misses. You have one chance to intercept during that time window. During the midcourse phase, the ICBM is in space, over 1000 kilometers above the Earth. It’s moving at several kilometers a second. In this test, it was over 4000 kilometers from the GBI’s launch point.

It’s around 10-20 metres long.

And you have to hit it.

This is, shall we say, not a trivial challenge?

Anyone assuming that their country’s missile defence systems entirely remove the possibility of nuclear attack is kidding themselves. Missile defence is just a part of the great game of deterrence played by the world’s few nuclear powers. If anyone launches, the world is still screwed.

Luckily for any remaining Cold War doomsayers, the GBI’s 50% intercept success rate is pretty nicely matched by the Russian Bulava ICBM’s 53% test success rate. And if your Red (/Green?) terror of the month is North Korea or Iran, can you imagine their missile programmes having anything like the success rate of the Russians’ or the Americans’?

So if all the ranty CNN commenters could get over it, it would be appreciated. The US needs missile defence, even though it isn’t perfect and never will be. Aegis has a better record than the GBIs anyway, did you forget that you had that too? North Korea is not going to nuke you tomorrow anyway.