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How the Guardian Anti-missile System Works

        Science | Explosives

Directional Infrared Countermeasure
The pointer/tracker system tracks an incoming missile and directs an infrared beam at the missile's seeker.
The pointer/tracker system tracks an incoming missile and directs an infrared beam at the missile's seeker.
Photo courtesy of Northrop Grumman

Guardian is known as a Directional Infrared Countermeasure (DIRCM) and relies on two distinct systems to defend against missile attacks. The first system includes ultraviolet sensors that detect an incoming missile. The second includes the transmitter that directs a beam of infrared energy at the missile’s seeker. Both systems are enclosed within a single compact pod, which mounts to the underside of a jet’s fuselage.

Here’s how the systems work together:

  1. When a MANPADS missile is fired, it produces all forms of energy across the electromagnetic spectrum. Sensors in Guardian’s missile-warning system detect the ultraviolet wavelengths and send a signal to the transmitter. Future versions of the Guardian solution could include sensors that detect two bands of infrared energy, making it easier to sense missiles at significantly greater ranges.
  2. Once it receives a signal from the missile-warning system, the pointer/tracker assembly tracks the missile as it approaches.
  3. A high-intensity gas arc lamp then fires a beam of infrared energy at the missile’s seeker.
  4. For the seeker, it's like having an extremely bright light shined in its “eyes.” But Guardian doesn’t simply blind the missile. Its laser beam has a special waveform that actually gets into the missile seeker’s guidance loop and causes an error signal to build, making the missile’s guidance system think it's off course.
  5. The guidance system responds by adjusting the missile’s flight path.
  6. The missile eventually becomes so off course it no longer poses a threat.
  7. The entire process occurs in two to five seconds and requires no action on the part of the aircraft crew. Once the aircraft reaches approximately 18,000 feet — the range of most MANPADS — the Guardian system shuts down until it is time to land.
Photo courtesy of Northrop Grumman

Feasibility

The technology used in the Guardian system has a proven track record in military applications. According to Northrop Grumman, NEMESIS has successfully completed more than 4,000 hours of flight testing, more than 200,000 jamming effectiveness tests, and more than 100 successful missile, live-fire engagements, including combat.

So the real question is not whether Guardian is effective, but whether the commercial airline industry can afford to implement the solution. According to a 2005 study conducted by RAND Corporation, it would cost an estimated $11 billion to install anti-missile systems on America’s 6,800 commercial airliners. Operating the systems after installation would cost up to $2.2 billion annually. Because of these figures and because resources available for Homeland Security are limited, RAND recommended that the United States look to other strategies that might be more cost-effective. But some experts weigh the cost of protecting airlines against the cost of a successful attack. For every aircraft downed, there would be $1 billion in direct costs, and indirect costs would be much more significant.

Seal of the U.S. Department of Homeland Security
Seal of the U.S. Department of Homeland Security

All of this is under consideration by the Department of Homeland Security. In January 2007, the department entered the third phase of its three-year feasibility study. In this phase, FedEx will fly 11 MD-10s with Northrop Grumman’s Guardian system for 18 months to test whether the equipment is cost-effective and reliable for commercial aircraft operations. A second team is studying another laser-based DIRCM system known as Jeteye. Jeteye, developed by BAE Systems, will be mounted on American Airlines’ Boeing 767s flown by carrier ABX Air. If one system is found to be more cost-effective and reliable, it could win the department’s approval. The addition of the Guardian system will not change the way the plan is flown. In fact, the system engages itself upon takeoff. If it is deployed to stop a missile, it will do so on its own; there is no need for the pilots to do anything. Once the plane hits 18,000 feet (out of range of most shoulder-fired missiles), the Guardian system will disengage until it is time to land the aircraft.