Second airship launched in test of missile defense system

1	The U.S. military has launched the second of two helium-filled airships near Baltimore to test an East Coast missile defense system.
2	The confirmed launch Wednesday at the Army's Aberdeen Proving Ground completes the aeronautical part of the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System, or JLENS.
3	The radar-equipped aerostats are tethered to concrete pads 4 miles apart.
4	They're designed to float unmanned at 10,000 feet.
5	During the three-year test, one balloon will continuously scan 360 degrees from upstate New York to North Carolina's Outer Banks, and as far west as central Ohio.
6	The other carries precision radar to help the military on the ground pinpoint targets.
7	The aerostats don't carry weapons.
8	Enemy missiles would be destroyed by weapons launched from the air, the sea or the ground.