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4 October 2002 |
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http://cm2000.cm.nctu.edu.tw/news/200204117.htm |
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WASHINGTON - Even before the Taliban crumbled, U.S. Defense Secretary Donald Rumsfeld boasted that unmanned spy planes, which beamed live pictures of fleeing Taliban and al Qaeda fighters to U.S. pilots and commanders, were one of the stars of the Afghanistan war. The Pentagon has budgeted over $1 billion to buy 37 more of the high-tech aircraft next year. But the military probably won't be able to fly them all. With the collapse of the commercial-satellite industry, the Pentagon faces a bandwidth crunch: a shortage of the communications hardware that links people on the ground and planes in the air. Bandwidth is a measurement of how much data can flow through a network of transmitters, receivers and satellites. More satellites make for a more robust network that can handle more data and more unmanned planes flown by people on the ground. Remote Control In late December, Air Force Capt. Elissa Beddow was told to use the Predator unmanned surveillance plane that she operates to hunt for some al Qaeda fighters trying to flee Afghanistan. Sitting in a ground station hundreds of miles away in Pakistan, Capt. Beddow directed the spy plane with a control stick, a computer keyboard and several television monitors that provided live video feeds. She flew the 27-foot-long aircraft up and down the road where the men had last been seen. Thirty minutes into the search, she spotted them. Over the same satellite link that let her fly the Predator and watch the video, she summoned a Navy fighter jet and led it to the mud hut where the men had parked their sport-utility vehicles. On the video feed, Capt. Beddow saw the al Qaeda fighters milling around their SUVs. "You almost wanted to scream, 'Run! Get out of the way! You're going to be killed!' " she says. A few minutes later, the fighters were all dead. In the 1990s, the U.S. military bet that by 2005 almost 1,000 new satellites would be available for weapons such as the Predator that rely on space-based communications. But the commercial-satellite industry, which the Pentagon was counting on to launch those satellites, fell on hard times. Of the 675 launches expected between 1998 and 2002, only 275 satellites reached space, according to Futron Corp., a Bethesda, Md., firm that tracks the industry. A Major Barrier Now, the scarcity of satellite links stands as a major barrier to President Bush's vision of transforming the military into a light, lethal force capable of striking anywhere in a matter of days. "The challenge of the future isn't building a great infantry carrier or artillery piece," says Lt. Gen. John Riggs, who is leading the Army's modernization effort. "The challenge is building a system that ensures we get the right information to the right place at the right time on the battlefield." Even in Afghanistan, a smaller operation than Kosovo or the Persian Gulf War, the military has felt the satellite squeeze. The Pentagon assigned six Predators and two larger Global Hawk unmanned planes to Afghanistan, but it has been able to keep only two Predators and one Global Hawk in the air simultaneously. To conserve satellite capacity, Global Hawk pilots have been forced to turn off some of the aircrafts' sensors and transmit fuzzier, lower-quality video, officials say. The problem will probably hamper the military at least through the next decade. In February 2000, the Defense Science Board, the Pentagon's internal think tank, concluded that the military would need an average of about 16 gigabits per second of bandwidth -- the equivalent of about 208,000 simultaneous phone calls -- to fight a major war in 2010. Today, the projected requirement, which is classified, is "significantly higher than what we forecast," says Army Brig. Gen. Stephen J. Ferrell, who is heading a study on the Pentagon's communications needs. Falling Short The Pentagon plans to launch three of its own satellites between 2004 and 2006, but Defense officials say the additional capacity will amount to only six to 7.5 gigabits. The military will have to make up the difference by buying more commercial-satellite links, but that won't be easy. In Kosovo the Pentagon struggled to buy less than one gigabit per second of capacity because of the scarcity of available satellite links. "All Defense Department-owned communication acquisitions over the next 10 years will not come close to meeting the bandwidth requirements," the Defense Science Board report concluded. Demand for bandwidth continues to grow as the services develop more data-intensive weapons systems. To reduce risk to men and women in uniform, all of the services are relying increasingly on remote-controlled weapons. Beaming intelligence back to bases in the U.S. for processing also lets the services slash the number of people and tons of equipment they bring to the battlefield. In 1996 and 1997, Pentagon officials decided to rely on the commercial-satellite industry to produce most of the hardware they would need for these new bandwidth-intensive weapons systems. The military then planned to lease capacity on the satellites. At the time, the growing industry appeared to be on the verge of providing huge amounts of bandwidth to anyone who wanted it almost anywhere on the globe. New companies such as ICO-Teledesic Global Ltd. -- backed by billionaires Bill Gates and Craig McCaw -- said they would use their satellite networks to sell telephone and broadband Internet service to businesses and consumers world-wide. Wall Street poured billions of dollars into the fledgling business. "Ubiquitous satellite communications and unlimited bandwidth seemed the destiny of the world," says Air Force Col. Dave Anhalt, who has studied the issue for the Secretary of Defense's office. Bandwidth Glut Fiber-optic cable, which carries huge amounts of information in the form of light beams, ruined the plan. It proved a cheaper and more reliable way of moving gigabits of information around the globe. Scores of companies built fiber-optic networks spanning the world, creating a bandwidth glut that has contributed to the demise of many telecommunications companies. The cable didn't help the military, which needs wireless connections to tanks, planes and ships. But the surge in fiber-optic networks hurt the satellite companies. In the past few years, ICO-Teledesic and about a dozen other companies -- including Motorola Corp.'s Celestri project and Hughes Electronics Corp.'s Spaceway project -- have had to cancel, scale back or postpone new satellite launches. Hints of a Problem The first hints of a problem for the military surfaced in Kosovo in 1999. During that war, the military's requirements exceeded all of the existing military and commercial-satellite capacity combined. After allotting available capacity to air operations, "we simply couldn't find enough bandwidth to support our ground forces," says Col. Steve Lisi, who was working at the time for Henry Shelton, then-chairman of the Joint Chiefs of Staff. The Clinton administration and the military had limited the use of ground forces, chiefly because of concerns about casualties and the Army's inability to mobilize a large, capable force quickly enough to make a difference. But the bandwidth crunch weighed on planners' minds, too, Col. Lisi says. "If we had decided to use ground troops, it would have been a real challenge," he says. The shortage has become more obvious in Afghanistan, largely because of the prominent role played by unmanned Predators and Global Hawks, which are by far the most voracious consumers of battlefield bandwidth. In the early days of the war, the Predator's usefulness seemed limited. It could beam live pictures of the battlefield to commanders in the U.S. and Saudi Arabia, where the air-operations center was based. But Predator pilots sitting in Pakistan couldn't talk to soldiers on the ground or to fighter pilots in the air to relay what was appearing on their video screens. The pilots were too far away from the ground troops to communicate with conventional radios, which have a limited range. "We were basically just a nice little reconnaissance platform," Capt. Beddow says. An Efficient Tool A few weeks into the war, however, Air Force officials rigged the Predators so that Capt. Beddow and her fellow pilots could talk via satellite to ground troops and fighter pilots in Afghanistan. Over time, the Predators proved an efficient tool for coordinating close air-support missions, in which advancing ground troops work with warplanes circling the battlefield to target and then kill an enemy from the air. Demand for the unmanned aircraft began to outpace supply. Throughout the war, the U.S. air commanders, stationed at Prince Sultan air base in Saudi Arabia, have had the final say on who got Predators for their missions. That didn't stop some generals, planning missions out of the U.S. and Afghanistan, from calling Predator pilots in Pakistan to demand one. "We'd politely remind them to call Prince Sultan," says Capt. Joe Rizzuto, a Predator pilot. Meanwhile, Predators and Global Hawks were sitting unused on the runway. The military didn't have enough ground stations for the remote pilots, but even if it had more of those stations, there wasn't sufficient bandwidth to fly all the available planes, defense officials say. There were other problems. In some areas of Afghanistan, satellite coverage was spotty and the video feed from the planes would fade in and out. To get videos from the Global Hawk planes back to the command center without overwhelming the system, pilots often would have to lower the quality, making the pictures fuzzier. But the military nevertheless saw unexpected potential in the spy planes. Back in Washington, they are often referred to as "high demand/low density assets," which Mr. Rumsfeld says is Pentagonese for "we didn't buy enough." He plans to remedy that in next year's budget with purchases that threaten to exacerbate the bandwidth crunch. The Pentagon currently plans to buy 22 Predators, 12 Army Shadow unmanned aerial vehicles and three of the big Global Hawks. Just one Global Hawk consumes about 500 megabits per second of bandwidth, or about five times the total bandwidth consumed by the entire U.S. military during the Gulf War. Seeking Solutions Led by the Air Force, the services are seeking new solutions. One option is to manage available bandwidth better. For example, satellite capacity currently assigned to the Predator or the Global Hawk goes to waste when those planes aren't flying and the capacity isn't used by other systems that need it. The services are working on new technology that would allow several systems to share bandwidth from a single satellite transponder. The Air Force's chief of staff, Gen. John Jumper, has pushed for outfitting airborne fuel tankers with antennas that would allow the lumbering planes to function as mini-satellites capable of relaying information within a 300-mile radius. To expand capacity substantially -- short of spending billions of dollars to launch new satellites -- the military needs an alternative technology. The Air Force Research Lab is working on communication lasers, which can carry far more information than traditional radio frequency, with the Massachusetts Institute of Technology's Lincoln Labs and a few private companies. But shooting a laser beam from space to an orbiting plane is fraught with challenges, in part because beams are degraded by moisture in the atmosphere. Defense officials are optimistic that by the end of the decade they'll be able to use lasers to shoot information from a plane flying at 50,000 feet -- above the clouds -- to an orbiting satellite. But the Pentagon probably will still have to depend on the commercial-satellite industry for a portion of its needs, says retired Air Force Gen. Bill Donahue, who has been tapped by the Pentagon to contribute to another bandwidth study. He has suggested that the Pentagon subsidize private companies' satellite launches in return for a dedicated slice of bandwidth in a time of war. The military has a similar deal with the airline industry, which is paid to make available a portion of its fleet in reserve for wartime use. The Bush administration is hesitant about putting money into the struggling industry. But Gen. Donahue says, "Ultimately, the Pentagon might be in the position of picking the winners and losers." Meanwhile, in a small, cinder-block building at Eglin Air Force Base near Pensacola, Fla., a team of 25 military officers and engineers led by Col. W. Rhys MacBeth is dreaming up new bandwidth-eating missions for Capt. Beddow's Predator. Earlier this year, the team rigged a Predator to drop a small sensor that lodges in the ground and beams seismic data, indicating vehicle or tank movement, up through a satellite to Predator pilots and commanders. If the sensor detects something, the pilots can swing their drone in for a closer look. Col. Rhys's team also has rigged the Predator to pass still photographs of potential enemy targets directly to fighter jets so the Predator pilots won't have to take the time to describe enemy positions orally. "Everyone has an idea of some kind of sensor or munition that they want to hang on the Predator," Col. MacBeth says. For now, the only limit to their plans is bandwidth, he says.
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