The Pentagon reportedly has suspended a costly missile surveillance program while officials investigate how one of the program's pilotless blimps broke free from its moorings in Maryland and floated into Pennsylvania, knocking out power for tens of thousands of people. 

Army spokesman Dov Schwartz told the Los Angeles Times the investigation would be "complete and thorough."

The Oct. 28 mishap was the latest setback for the $2.7 billion JLENS (Joint Land Attack Cruise Missile Defense Elevated Netted Sensor) program. The two blimps had been in testing mode, hovering some 10,000 feet over the Washington D.C. area and carrying sophisticated radar designed to detect and track airborne threats including cruise missiles. Operated by NORAD (North American Aerospace Defense Command), the blimps are supposed have 360-degree situational awareness and be able to stay aloft for 30 days at a time.

The Los Angeles Times reported that the runaway blimp had been taking part in an exercise that was scheduled to begin in January. However, problems with computer software delayed the launch of a required second blimp until mid-August.

JLENS has endured bad publicity from the start. In 2010, the prototype airship costing the Pentagon about $182 million was destroyed when a civilian blimp unmoored in a storm and crashed into it at a manufacturing facility in North Carolina. Then, after a series of problems with cost and performance, the Pentagon was forced to scale back the project in 2012, effectively quashing production of any new machines beyond the two already produced.

In the meantime, the reviews have been lackluster at best -- in 2012 and 2013, the Pentagon’s Operational Test and Evaluation Office said the blimps were not meeting operational goals, in one case charging that JLENS “did not demonstrate the ability to survive in its intended operational environment.” The evaluation also found flaws in the airships’ software and communications programs.

But with consistent lobbying by Raytheon, the program has lived on like a “zombie,” racking up $2.7 billion in costs by 2014, The Los Angeles Times reported in September.

Despite the setbacks and criticism, JLENS was spared from a $5 billion cut to a revised version of the massive defense policy bill to align it with the new budget agreement President Obama signed into law.

Obama had initially vetoed the $612 billion defense authorization bill over a larger dispute over government spending. But that dispute was resolved and the leaders of the Senate and House Armed Services committees announced Tuesday that they had agreed on how to trim $5 billion from the original bill to bring it in line with the budget agreement at a total of $607 billion.

Rep. Jackie Speier, D-Calif., slammed the program in a statement, calling it "a 'zombie program' that doesn’t provide an advantage over aircraft that we’ve already bought." However, the Los Angeles Times reported that House Armed Services Committee chairman Mac Thornberry, R-Texas, told a private meeting of members and staff that Republicans still back the system.

Among the adjustments were $230,000 for the next-generation bomber to replace the aging bomber fleet — money that the Pentagon wasn't going to spend anyway because it took longer than expected to sign the contract to build it; $1 billion saved because of lower-than-anticipated oil prices; and $442 million in readiness funds for the Army and National Guard.

Fox News' Kelley Beaucar Vlahos and the Associated Press contributed to this report. 

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