Pentagon spy blimp breaks free, floats menacingly over US East Coast

The US military is scrambling to recover an expensive spy blimp that broke loose from its moorings and is threatening air traffic north of Baltimore, Maryland. Fighter jets are shadowing the helium-filled balloon as it drifts over Pennsylvania.

Known as an “aerostat,” the floating surveillance platform has been moored at the Aberdeen Proving Ground, northeast of Baltimore, since 2014. It broke loose around 12:20 local time Wednesday.

According to the US Army’s North American Aerospace Defense Command (NORAD), the runaway blimp was first reported at an altitude of about 16,000 feet (4.8 km). It is trailing 6,700 feet (2 km) of cable below, posing a navigational hazard to aircraft.

Around 3 p.m. authorities in central Pennsylvania reported fires on the ground as the tether tore up power lines. Some 21,000 residents were without power.

Local media initially reported that the errant airship landed in Columbia County, Pennsylvania, somewhere between Jerseytown and Millville, around 65 miles west of Scranton.

Eyewitnesses on the ground, however, said the blimp was still airborne, slowing down as the dragging tether pulled it steadily lower.

NORAD said the "partially deflated" blimp made landfall just after 4 p.m. near Williamsport, Pennsylvania.

The 240-foot (74-meter) blimp is part of a program by the weapons manufacturer Raytheon named JLENS, which stands for “Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System.” The airborne radar has the ambitious objective of giving early warnings of low-flying missiles and planes.

The 17-year program has cost the Pentagon around $2.7 billion, according to a recent feature in the Los Angeles Times. Raytheon lobbied hard for its survival after the Army tried to cancel it in 2010, leading defense commentators to dub JLENS a "zombie" program: costly, ineffectual and seemingly impossible to kill.

JLENS failed spectacularly on April 15 this year, when a postal worker from Florida flew unchallenged through a restricted area around Washington DC in a gyrocopter, landing in front of the US Capitol.

Authorities in Maryland and Pennsylvania have issued statements that they are tracking the blimp, warning the population to call 911 and not to attempt to engage the runaway sensor platform on their own.

While two F-16 fighters have been scrambled to follow the renegade aerostat, the military hopes to recover the multi-million dollar sensor technology aboard the JLENS rather than shoot it down.