The American military has been working since 1996 on a tricked-out 747 that could blast ballistic missiles out of the sky with a ultra-powerful laser. After 14 years of promising “the American people their first light saber,” the Missile Defense Agency finally pulled it off Thursday night at 8:44 p.m
It’s one of a number of steps forward for real-life ray guns in the past year or so. “Solid state” electric lasers finally hit what’s commonly considered battlefield strength. A laser-equipped Air Force gunship disabled a truck with its energy beam. A ground-mounted ray gun blasted drones out of the sky. But all of those energy weapons were weak — and the engineering challenges limited — compared to last night’s shoot-down.
A short-range, Scud-like ballistic missile was launched from an at-sea mobile launch platform near the Point Mugu Naval Air Warfare Center, off of the central California coast. “Within seconds, the Airborne Laser Test Bed [ALTB] used on-board sensors to detect the boosting missile and used a low-energy laser to track the target. The ALTB then fired a second low-energy laser to measure and compensate for atmospheric disturbance. Finally, the ALTB fired its megawatt-class High Energy Laser, heating the boosting ballistic missile to critical structural failure. The entire engagement occurred within two minutes of the target missile launch, while its rocket motors were still thrusting,” according to a statement from the Missile Defense Agency. [Update: That's the video of Thursday night's test, above.]
This is a test the MDA was hoping to conduct in 2002, after spending about a billion dollars. But the Airborne Laser ran into all kinds of problems along the way. The chemicals the jet depended on to generate its high-strength laser weighed down the 747. Getting the laser to accurately zap through the atmosphere proved tougher than anticipated. The Airborne Laser eventually ballooned into a $7.3 billion project. Finally, Defense Secretary Robert Gates got so fed up, he told the MDA to end the Airborne Laser program after a single jet.
“I don’t know anybody at the Department of Defense who thinks that this program should, or would, ever be operationally deployed,” Gates told Congress last year. “The reality is that you would need a laser something like 20 to 30 times more powerful than the chemical laser in the plane right now to be able to get any distance from the launch site to fire.”
So, right now the [jet] would have to orbit inside the borders of Iran in order to be able to try and use its laser to shoot down that missile in the boost phase. And if you were to operationalize this you would be looking at 10 to 20 747s, at a billion-and-a-half dollars apiece, and $100 million a year to operate. And there’s nobody in uniform that I know who believes that this is a workable concept.
But Gates did add that the concept of using laser and other speed-of-light “directed energy” weapons to knock down missiles still had promise. It might be the only way to stop missiles in “boost phase” — when they were just getting off of the ground.
That’s why many in the military will be excited about Thursday night’s test. As the MDA notes, it’s the first time a laser in the sky has successfully downed a missile. And even if this particular weapon doesn’t work out, the technology developed can be used for later systems. “The revolutionary use of directed energy is very attractive for missile defense, with the potential to attack multiple targets at the speed of light, at a range of hundreds of kilometers, and at a low cost per intercept attempt compared to current technologies,” the agency notes.
“Less than one hour later,” there was a second test, with another missile. The Airborne Laser lit it up. But didn’t destroy the thing. That test was for another day.
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The ALTB in flight. 
An infrared video of the Airborne Laser Testbed (right) disabling a threat-representative short-range ballistic missile (left) during the initial boost phase. 
The United States Missile Defense Agency have announced that their airborne laser system has successfully shot down a ballistic missile for the first time. In a test on Thursday the "Airborne Laser Testbed" (ALTB), a modified Boeing 747-400F, detected a boosting short-range missile and tracked it using a low-energy laser. A second low-energy laser was used to measure and compensate for atmospheric disturbance, before the aircraft's High Energy Laser was used to destroy the target.

The missile was liquid-fuelled and said to be "threat-representative", possibly similar to a Scud. It was launched from sea, and shot down by the ALTB within two minutes. In a second test less than an hour later, a solid-fuel missile launched from a ground location was also successfully hit by the High Energy Laser, but deliberately not destroyed. A similar missile was destroyed on February 3.

In a press release announcing the successful tests the Missile Defense Agency said: "The revolutionary use of directed energy is very attractive for missile defense, with the potential to attack multiple targets at the speed of light, at a range of hundreds of kilometers, and at a low cost per intercept attempt compared to current technologies."

The ALTB is described as a "pathfinder" for the use of directed energy in missile defense. It is designed to operate at high altitudes above the clouds, and to detect and destroy ballistic missiles soon after launch whilst they are still in their boosting phase. The aircraft is provided by Boeing, the main laser by Northrop Grumman, and the control systems by Lockheed Martin.

"Through its hard work and technical ingenuity, the government-industry team has produced a breakthrough with incredible potential," stated Greg Hyslop, vice president of Boeing Missile Defense Systems. He said that the experiment had "made history". 

The US has been working on the program since 1996, and has faced numerous problems in that time. The megawatt-class High Energy Laser is known as the chemical oxygen iodine laser (COIL), and consists of six modules, each as large as an SUV. The sheer weight of chemicals needed was almost too much for the 747 jet. The laser also had problems with accuracy due to atmospheric conditions.

February's tests were originally scheduled to be carried out in 2002. The amount spent getting the project to this stage has also risen from a planned US$1 billion to $7.3 billion. Last year, Secretary of Defense Robert Gates cut the program back to a single jet for research, suggesting it would not see actual deployment.

“The reality is that you would need a laser something like 20 to 30 times more powerful than the chemical laser in the plane right now to be able to get any distance from the launch site to fire,” Gates told Congress. "So, right now the jet would have to orbit inside the borders of Iran in order to be able to try and use its laser to shoot down that missile in the boost phase."

Gates also raised concerns at the large number of planes that would be required, and the ensuing cost. However, he said that directed energy weapons still had potential for missile defense.