It’s larger than a football field and can fly 20,000 feet in the air for 21 days at a time. After two years in development, later this week the U.S. Army is expected to test launch a new-generation surveillance blimp designed to float above warzones, intercepting communications and monitoring people on the ground below.

Up to three so-called “Long Endurance Multi-Intelligence Vehicles” were commissioned by the Army in 2010 as part of a $517 million deal cut with defense and aerospace manufacturer Northrop Grumman. The 300-foot-long, unmanned, helium-filled airship, Grumman claims, will “shape the future” of the military’s intelligence-gathering capabilities—adding a new dimension to its existing fleet of surveillance aircraft by providing a “persistent unblinking stare” from the sky.

A prototype LEMV is set to take off sometime between June 6 and 10 from New Jersey’s Joint Base McGuire-Dix-Lakehurst before heading to Florida to be fitted with “a custom-designed gondola containing the blimp’s cameras and radios,” according to Wired. If the trial run on domestic soil is successful, it is thought the airships will then be sent to Afghanistan.

The army’s significant investment in LEMVs is part of what has been described as a blimp renaissance. Large blimps have not been widely used by armed forces since they were retired from service by the U.S. Navy in 1962 , in part due to a series of accidents, but also because they are not as technically robust as traditional aircraft. They are slow moving, don’t perform well in bad weather, and rely on helium, a gas that is in short supply.

In recent years, however, they have proven increasingly popular. The army has already deployed some small surveillance blimps in Afghanistan. And the Department of Homeland Security has also tested camera-mounted blimps for domestic border surveillance—using a 75-foot computerized “aerostat” to make arrests in Nogales, Ariz., earlier this year.

Blimp boosters have ambitious plans for large, long-deployment blimps capable of spying. It was revealed in 2009 that the Pentagon wanted to build a “revolutionary” blimp that would float 65,000 feet above the Earth for 10 years, providing constant surveillance. And one year later, then-Defense Secretary Robert Gates ordered the Air Force to begin building a huge 370 foot “Blue Devil” airship that he said was “urgently needed to eliminate combat capability deficiencies” (though the Blue Devil project is now expected to be canceled due to a lack of funding).

But it’s not just the United States that is keen to exploit blimps’ eye in the sky capabilities. Police forces in the United Kingdom have previously considered investing in a 72-foot long airship—the G22, developed by Lindstrand Technologies—for domestic surveillance. And Israel has used blimps to spy on Gaza, though their success has been limited. In March, an “observation balloon” operated by Israeli security forces reportedly crashed after a collision with a civilian crop duster.

Correction, June 5, 2012: This item originally misstated from where the blimp will launch. It will be launched from Joint Base McGuire-Dix-Lakehurst.