Via Raytheon.

A 242-foot-long military surveillance blimp designed to protect D.C. and the East Coast from cruise missiles, unmanned aircraft and other threats will be tested next week.

The Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System, or JLENS, will be launched from the Army’s Aberdeen Proving Ground in Maryland, Venture Beat reported: “Designed to patrol the eastern seaboard from an altitude of up to 10,000 feet, JLENS is made up of two blimps, each equipped with a different radar system, which can spot potential incoming threats from up to 340 miles away.”

The North American Aerospace Defense Command, or NORAD, is leading the three-year test:

The first JLENS radar is expected to be airborne in mid-December 2014, followed approximately six weeks later by the second radar. During the three-year exercise window, JLENS capabilities will be fully explored in a real-world environment as part of the NORAD air defense architecture to evaluate operational utility in support of NORAD’s homeland defense mission.

The JLENS is a key contributor to joint air and cruise missile defense capability objectives. It can extend the air defense umbrella of protection over population centers, critical infrastructure, and military assets, enabling ways to improve our national security. The JLENS wide area surveillance capability should increase decision time available to respond efficiently and accurately for the defense of the NCR.

Approximately 130 operators and their families will be assigned to APG to support the exercise. The soldiers have received very comprehensive, months-long training, and are well prepared to operate the system at Aberdeen.

Here’s more from Raytheon, the maker of the blimp:

There’s a good reason senior military leaders are concerned about cruise missiles. They fly low, making them really hard for a ground-based radar to spot; there are lots of them out there; and some of them can even be launched from innocent-looking cargo containers.

Cruise missile defense is literally JLENS’s middle name. When the system is operational at Aberdeen Proving Ground, it will become part of the defenses that help protect the National Capital Region — the federal government’s name for the metro Washington, D.C. area.