Hugh Pickens writes writes: "Reuters reports that pair of bulbous, helium-filled "aerostats" — each at 243 feet more than three quarters the length of a football field at will be moored to the ground and fly as high as 10,000 feet, as part of a high-tech shield designed to protect the Washington D.C. area from an air attack like the one that took place on September 11, 2001, when Al Qaeda militants hijacked American Airlines Flight 77, a Boeing 757, and crashed it into the Pentagon. One of the aerostats carries a powerful long-range surveillance radar with a 360-degree look-around capability that can reach out to 340 miles. The other carries a radar used for targeting. Operating for up to 30 days at a time, JLENS is meant to give the military more time to detect and react to threats (PDF), including cruise missiles and manned and unmanned aircraft, compared with ground-based radar and is also designed to defend against tactical ballistic missiles, large caliber rockets and moving vehicles that could be used for attacks, including boats, cars and trucks. "We're trying to determine how the surveillance radar information from the JLENS platforms can be integrated with existing systems in the National Capital Region," says Michael Kucharek, a spokesman for the North American Aerospace Defense Command. Washington is currently guarded by an air-defense system that includes Federal Aviation Administration radars and Department of Homeland Security helicopters and fixed-wing aircraft on alert at Reagan National Airport to intercept slow, low-flying aircraft."