On February 12, 2010, the U.S. Missile Defense Agency (MDA) used the Airborne Laser Test Bed (ALTB) mounted on a Boeing B-747 jumbo jet to shoot down a liquid-propellant and a solid-propellant target missile.

The ALTB project is one of the MDA's most ambitious and long-term programs. Washington launched its initial research in this sphere in the 1970s. At that time, an NKC-135-ALL aircraft, a modified version of the KC-135 Stratotanker, was built and used as an airborne laboratory.

United Technologies built a 10-ton, 04-0.5-MWt CO2 laser system for the program. The NKC-135-ALL was involved in a series of tests in the late 1970s and the early 1980s. Although the tests proved that a laser weapon was feasible, it had a range of just a few kilometers and therefore lacked any military prospects.

In 1985, a laser weapon used in ground tests heated up the stationary fuel tank of a Titan-1 intercontinental ballistic missile simulating a Soviet ICBM a thousand meters away causing it to explode.

Such tests, as well as the NKC-135-ALL program, were conducted under the Strategic Defense Initiative (SDI) program. However it was impossible to develop a feasible missile defense system based on airborne laser weapons because most of the technical problems remained unsolved.

The Soviet Union also implemented an airborne laser weapon program and built a Beriev A-60 aircraft, an upgraded version of the Il-76 transport aircraft. Although Moscow virtually mothballed the program after the break-up of the U.S.S.R. in late 1991, the media reported last year that it had been resumed.

The United States resumed work on airborne laser weapons in the late 1990s after the issue of implementing the National Missile Defense Program (NMD) was raised. Initially there were plans to build two prototype and five production aircraft by 2012.

However, it was later decided to scale down the program, due to skyrocketing costs. Although a prototype aircraft was scheduled to be completed by 2012, Washington decided not to build it and retained only one YAL-1 prototype, work on which began in 2000.

What is the ALTB's potential? Although there is no exhaustive information on the February 12 tests, some conclusions can be drawn on the basis of available reports.

The Boeing YAL-1 Airborne Laser (ABL) weapons system has three laser systems, namely, a Track Illuminator Laser (TILL) for illuminating the target and adjusting the parameters of the laser weapon's optical system, a Beacon Illuminator Laser (BILL) for reducing atmospheric aberration, and the six-module High-Energy Laser (HEL) weapon system.

The YAL-1 can hit ballistic missiles during their boost phase and has a range of 200-250 km. The effective range is limited by the laser unit's power, the laser beam's atmospheric dissipation, atmospheric aberration affecting siting accuracy and the laser-beam gas breakdown effect which has not yet been eliminated. Moreover, an excessively powerful laser unit could overheat the fuselage and cause the plane to crash.

These factors and the system's low rate of fire currently make it possible only to intercept individual missiles at short range. It appears that such systems will be unable to neutralize an all-out nuclear strike in the next 20-30 years.

Speaking of a hypothetical Russian-U.S. conflict, airborne laser weapons would have to be deployed in Russian air space in order to be able to intercept Russian missiles in their boost phase and during the separation of their multiple independently targetable reentry vehicles (MIRVs). In fact, they would have only 3-5 minutes to accomplish this objective.

However, even Russia's problem-ridden air-defense system would not allow a B-747 to roam free in national air space.

Airborne laser weapons present a greater threat to strategic ballistic missile submarines which either patrol Russian territorial waters or international waters. However, there is one limitation. As the submarines spend most of their time underwater, laser-carrying aircraft could not quickly reach the optimal firing position necessary for a successful missile interception.

Consequently, this project's current version threatens only countries such as Iran or North Korea which have a small territory and are therefore unable to deploy missile bases far from their borders.

In the next several decades, the potential for laser weapons may be enhanced, especially if it becomes possible to deploy them on hypersonic suborbital platforms operating in the upper atmosphere where laser dissipation is minimized.

However, it would be pointless to deploy such weapons aboard spacecraft, unless payload mass is increased drastically because it would otherwise prove impossible to orbit high-power laser units.

It is impossible to struggle against the development of laser weapons. Practical experience shows that legal documents seldom effectively limit technical progress. Consequently, we must start preparing for a new round of the arms race now.

It is common knowledge that Russia is currently developing new-generation ballistic missiles which will be able to breach missile-defense systems with laser weapons. This objective can be accomplished by reducing a missile's boost phase, enhancing the maneuverability along this flight leg, etc. Analysts are discussing other measures that can shield missiles from laser beams.

Naturally, Russia must conduct independent research in this area to be able to manufacture airborne laser weapons and to effectively cope with similar enemy systems. Media reports about the reinstatement of the A-60 program are particularly important in this context.

The opinions expressed in this article are the author's and do not necessarily represent those of RIA Novosti.