A US government surveillance airship broke free of its moorings and headed to Pennsylvania, carrying its load of very sensitive and super-secret hardware.

The blimp is part of Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS), which is a radar and surveillance system designed to spot vehicles, boats, and drones from the air. It consists of two 70-meter-long airships containing VHF and X-band radar systems floating 10,000 feet up which send fire control data back to missile batteries on the ground.

JLENS aerostat detached from mooring station in Aberdeen Proving Grounds, MD. NORAD working interagency partners to address safe recovery. — NORAD & USNORTHCOM (@NoradNorthcom) October 28, 2015

At 1154 ET (1554 UTC) today the tether holding one of the blimps in place snapped and the airship headed east under wind power, trailing about 6,700 feet of tether. It was tracked by two F-16 fighters, and the Aberdeen Proving Ground, which was running the JLENS program, says it has the situation under control.

"Emergency personnel are tracking the aerostat which is still aloft in moving toward Pennsylvania," it said in a statement.

"Anyone who sees the aerostat is advised to contact 911 immediately; people are warned to keep a safe distance from the airship and tether as contact with them may present significant danger."

Needless to say there have been plenty of sightings – a huge blimp floating over head is difficult to miss – and social media is filling up with spottings under the name @AberdeenBlimp. At the time of writing, the blimp was over Bloomsburg, Pennsylvania.

Be free @AberdeenBlimp go live your dreams and save your people pic.twitter.com/udcWbicpou — Karma (@useless_phuck66) October 28, 2015

"The Governor's Office is in communication with the Pennsylvania Emergency Management Agency, the Pennsylvania State Police, the National Guard, and the appropriate authorities with the federal government," said state governor Tom Wolf.

"We are closely monitoring the situation, and we will work with the appropriate authorities to respond to any resource requests and assist in any way possible."

According to Raytheon, which manufactured the airship, there are systems in place to bring the airship down safely, but whether those can be activated remotely remains to be seen. If not, the craft may have to be shot down. ®

Breaking as The Reg went to press

It appears the blimp has been stopped. Excitement over.

BREAKING: State police: Military blimp that broke loose, drifted over Pennsylvania is on ground, secure. — The Associated Press (@AP) October 28, 2015

Bootnote

Technically the aircraft isn't a blimp, which is defined as a balloon without an internal framework. The correct terminology is an aerostat, but blimp is a much more fun word to say and thus tends to get affixed to any floating gasbag.