U.S. warplanes vulnerable to shoulder-fired missiles.

In Operation Desert Storm, the United States lost at least 20 aircraft to heat-seeking missiles. Ten years later, Pentagon officials have taken a cautious approach in planning air strikes on Afghanistan, fearing the threat from shoulder-fired infrared missiles.

"Our strike planners worry about the man-portable SAMs [surface-to-air missiles], because we've learned the lesson of those who went before and of our own experiences," said Marine Corps Lt. Gen. Gregory S. Newbold, Joint Staff director of operations. Such apprehension shapes the planning of each strike -- the altitude and "the way in which we fly and the protection which escorts our missions," Newbold told reporters during a briefing on Operation Enduring Freedom.

Shoulder-fired air defenses, commonly known as Manpads, have been around since the 1960s. They are of particular concern to commanders and aircrews executing close-air support missions, because, for the most part, U.S. tactical fighter aircraft do not have warning systems against infrared missiles. If a missile is fired from a mile away, for example, it could hit the aircraft three or four seconds later. That is not enough time for a human to react and get away.

U.S. tactical fighter/bomber aircraft participating in air strikes over Afghanistan generally have flown at a safe altitude of 15,000 feet or higher, outside the range of SAMs. During the first few weeks of the conflict, Pentagon officials reported that most of Afghanistan's fixed SAMs had been destroyed. But it is not clear how vulnerable U.S. warplanes remain to the threat of Manpads operated by Taliban militias.

"Our air forces do not have adequate missile warning systems," said Congressman Joseph Pitts, R-Penn., who chairs the so-called Electronic Warfare Working Group. Pitts has been a long-time advocate of increased spending in electronic countermeasures to protect aircraft.

"We must be prepared [to defend against] infrared-guided, man-portable SAMs," Pitts told a conference on Capitol Hill. "We need to ramp up self-protection countermeasures," he said. "This is especially important for large aircraft, such as the C-130 and the C-17 cargo airplanes."

The Air Force C-17 has been used in Operation Enduring Freedom to air-drop humanitarian food rations to the Afghans. According to press reports, these drops were made from high altitudes, above 20,000 feet, to avoid enemy fire. During the conflict, both the Air Force and the Special Operations Command have operated several variants of the C-130 Hercules.

Retired Air Force Maj. Gen. John Corder, who flew more than 100 missions over North Vietnam in the 1960s, said that infrared threats are "very difficult."

Most U.S. aircraft have flares that can suppress infrared missiles, Corder said in an interview. But no matter how many flares a pilot has at his disposal, if he is not warned of an incoming missile, he does not have enough time to activate those flares, he said. "The problem is when to put the flares out."

If a pilot does not see the missile being launched, Corder explained, he "will die," unless the aircraft has a missile-warning system. "We don't have those on combat airplanes today," he said.

To cope with the IR threat, Corder added, aircraft are equipped with flares of various kinds. "The problem is that most guys who are shot down by IR missiles are shot down unaware, with a full load of flares.

"You could have one hundred million flares on the airplane, but you don't know where to put them out," because there is no time to react, he said. Under these circumstances, he said, the pilot is faced with two choices: drop flares when "he thinks that he is in trouble," or fly at altitudes above 15,000 feet.

What is needed, said Corder, is a missile-warning system that will automatically eject a flare when the aircraft is under attack. "We haven't bought those systems," he said.

The Defense Department has focused on acquiring infrared countermeasure systems to protect large aircraft, such as the C-130 and the C-17. Traditionally, large airplanes have defended themselves from heat-seeking missiles by dropping flares. As IR missiles became more advanced, they also became more resistant to this type of countermeasure.

"Modern missiles can attack airplanes from any aspect and are fast enough to engage tactical aircraft," said Arnold Welch, vice president for infrared countermeasures programs at Northrop Grumman Corp.

The company is producing the DIRCM (directional IR countermeasure system) for the Defense Department. The newest version of the system, called Nemesis, was designed to defeat infrared surface-to-air missiles.

Shoulder-fired Manpads "can go anywhere [and] cannot be seen," Welch said during a briefing to reporters last June.

He estimated that there are more than 500,000 Manpads worldwide. They range in cost from $20,000 to $70,000 per system.

"IR countermeasures have come along lately," Welch said. The Defense Department has paid more attention to those systems, given that a greater number of aircraft have been lost to IR missiles than to RF (radio-frequency) guided weapons.

An effective IR countermeasure system requires a missile warning mechanism that detects where the threat is coming from, and can direct IR energy precisely in its path, to jam the missile, Welch explained. "As the threat evolved, it became necessary to take the available energy that comes out of the jammers and focus the energy to a very narrow beam and point it directly at the threat."

When a missile is fired, he said, "a missile-warning system tells us where it's fired from." Typically, there would be four to five DIRCM units around a large airplane. The threat location information is processed by a computer, which tells one of the transmitter units to slew over to where the threat is coming from, tracks the threat and jams it with infrared energy. "Then, the threat goes off into a different direction," Welch said.

This whole process takes a few seconds. "The pilot doesn't have to do anything," he said. "There is a cockpit indicator unit that will tell the pilot that a missile has been approaching and it's been jammed."

Large transmitters are required for big aircraft, especially in the rear, said Welch. The company produces both small and large transmitters, for various aircraft sizes. Other companies, such as BAE Systems and Raytheon also make these systems.

In Nemesis, a missile-warning system picks up the bright flash, indicating a launch, said Welch. "In the blink of an eye, the turret transmitter points to that missile and starts communicating with the missile, telling the missile to fly off and steering the system in the direction that the DIRCM system decides, well away from the aircraft." The pilot never sees the missile launch.

DIRCM originally was a U.K. Ministry of Defense program that began in 1989. The U.S. Special Operations Command signed on to the project in 1993. A contract was awarded to Northrop Grumman in 1995 to install DIRCM on several aircraft, from small helicopters to large fixed-wing aircraft. It's made up of three line-replaceable units (modules), said Welch. "You may need one or more turrets for larger aircraft."

Large aircraft with big engines are vulnerable, because they have an enormous infrared signature. That means that an IR missile can go after larger aircraft more easily than smaller aircraft, from a longer range. "Large aircraft have to put out jamming energy that is larger than the aircraft signature," Welch explained. "In order to do that, we use a large turret."

The Nemesis system is being installed on 14 types of aircraft for U.S. and U.K. military forces.

This technology, said Welch, allows aircrews to plan combat tactics much differently than was previously possible. "They can be more aggressive, more confident," he said.

The same technology, Welch said, could be adapted for tanks or ships.

"Customers want something that is low cost," he said. "Typically, ground vehicles are exposed to more than just IR threats -- there are landmines, top-attack threats. The customers want a solution that does it all. This might be a piece of it."

Currently, the only programs that have been funded by the Defense Department are for aircraft.

Last month, Northrop Grumman received a $66 million U.S. Air Force contract to develop and produce a laser-based version of the DIRCM infrared countermeasures system.

The project is called Large Aircraft Infrared Countermeasures (LAIRCM) and is designed to protect big cargo airplanes from sophisticated heat-seeking missiles. The contract has production options worth up to $112 million.

The Air Force plans to install the LAIRCM equipment on 20 C-130 and C-17 transport aircraft.

In July, the Electronic Warfare Working Group published an "issue brief," asking the Air Force to invest in the next-generation technology for IR missile protection, called CLIRCM (close-loop infrared countermeasures). The author of the paper, Rep. Tom Sawyer, D-Ohio, said that CLIRCM technology "will provide aircraft self protection from IR missiles at about half the cost of the initial open-loop LAIRCM and will enable the system to assess the characteristics of an incoming missile and defeat its targeting system."

Research work on CLIRCM has been under way at the Wright-Patterson Air Force Base, in Dayton, Ohio, for nearly three decades and is now being moved to the Air Force Research Laboratory, also in Dayton. The new program is called laser IR countermeasure flyout experiment (LIFE). The closed-loop system, Sawyer wrote, "can rapidly identify and defeat the enemy missile."

The Air Force tested the LIFE technology successfully about a year ago at the White Sands Missile Range.