SALT LAKE CITY — The skies over the Utah desert are becoming the test site for a new fleet of hulking high-tech dirigibles the U.S. military is hoping will give battlefield commanders a bird's-eye view of cruise missiles and other threats.

One of the unmanned balloons — a 242-foot-long craft known as an aerostat — was launched Wednesday morning about 80 miles west of Salt Lake City, at a military-owned tract of desert that resembles the terrain of Afghanistan. It stayed aloft for about three hours before it was pulled back down as planned.

It was the first of several tests expected in the coming year or so in Utah, according to Dugway Proving Ground spokeswoman Paula Nicholson. More flights could come this week.

The dirigibles are outfitted with radar and communications systems to provide long-range surveillance of threats from aircraft, ballistic and cruise missiles.

Raytheon Co. was awarded a $1.4 billion contract from the Army in 2007 to design, build and test the aerostats.

More tests planned for later in the year include over the remote northern portion of the Great Salt Lake and parts of the Snake Valley.

The aerostats were first flight-tested in Elizabeth City, N.C., last summer but were limited to a height of 3,000 feet. In Utah, they are expected to fly some 10,000 feet above the Air Force's Utah Test and Training Range, where air space is restricted up to 58,000 feet.

The dirigibles, expected to be capable of staying aloft for a month, are tethered to processing stations on the ground. They don't need an airstrip to launch and could also be tethered to ships.

Officials said the aerostats will be less expensive to maintain and operate than conventional aircraft-based radar while providing a battlefield view of threats.

"Not only will it expand the view well over the horizon, but do so at the least cost to the taxpayer. This is a critically needed capability as we continue to prosecute the global war on terrorism," Dugway's commander, Col. William E. King IV, said in a statement.