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The US Missile Defense Agency (MDA) has finally – but military experts say the system is not good enough for combat.

A liquid-fuelled rocket – thought to be a Scud-B, similar to those being developed by Iran and North Korea – was fired from a ship off the coast California on 11 February.

Within the next 20 seconds, the “airborne laser testbed” onboard a modified Boeing 747 locked-on to it with two low-powered tracking lasers, then a laser beam of several megawatts, to heat-damage the missile’s skin. If such damage is done while booster rockets are still firing, the stresses caused by the acceleration can .

At the same time as its announcement that the airborne laser had shot down the liquid-fuelled rocket, the MDA also reported that the laser had downed a solid-fuel rocket launched from land on 3 February. An attempt to hit another solid-fuel rocket shortly after the successful test of 11 February failed.

Out with a bang

are planned, and the airborne laser is being demoted to a research project. Defense experts say this is because the system must get within a few hundred kilometres of a missile launch within its first 2 minutes to work, limiting its military usefulness.

“The test shows the system can track a target and focus its beam long enough to destroy it, which is impressive,” says Geoff Forden of the at the Massachusetts Institute of Technology. “But this is not representative of a combat engagement.”

The laser seemed relatively close to the target, and fired before the missile was moving very fast, making both tracking and destruction easier, says Forden. “I do not expect them to have much greater ranges later.”

In the last decade the US has spent $1 billion on lasers for missile defence, once dubbed “Star Wars”. The MDA did not request any money for airborne laser tests for next year.