Blimps are experiencing a bit of a renaissance. Recently Montabello, Calif.-based Aeros said it was working on a rigid airship that could fly like a plane and float like a balloon. And now Raytheon has just finished testing a military aerostat of that, starting next year, will be a first line of defense for Washington, D.C.
It's called JLENS, for Joint Land Attack Cruise Missile Defense Elevated Netted Sensor, and it's a pair of radar-equipped helium blimps tethered to the ground that give personnel the ability to see further away than with ground-based radar. The two blimps work together with one using radar to "see" an enemy target and the other guiding a missile to destroy it.
Unlike a true airship, an aerostat doesn't have it's own power source or drive system. The concept goes back to World War I and World War II, when tethered balloons were used to defend against dive-bombers. Modern versions focus on surveillance.
Raytheon's aerostat is 75 yards long and hovers at about 10,000 feet. This gives it a 360-degree view over the horizon that is not blocked by trees, hills or houses. At that height, any aircraft, drone, cruise or short-range ballistic missile can be detected up to 320 miles away. That range allows JLENS to alert military personnel minutes before an attack. Ground-based radar systems may only provide a few seconds.