Pentagon Tests Blimp Over D.C.

A developmental Army surveillance blimp (search) made an extended appearance over the nation's capital Wednesday, buzzing over the Pentagon (search) and other landmarks in what officials said was a demonstration of a technology that could be used to protect troops.

The 178-foot-long white blimp — the military prefers to call it an "airship" — is equipped with infrared and optical cameras and can transmit pictures to controllers on the ground. Similar equipment is already used in Iraq (search) and Afghanistan, mounted on tall towers or tethered balloons called aerostats, giving security forces a bird's-eye view of what's happening at the periphery of a military base or airfield.

Put cameras on blimps and they can patrol roadways, pipelines and towns, military officials said. Compared with other military hardware, blimps are cheap — running $2 million to $4 million each.

Navy Cmdr. Mike Giauque, a deputy project manager for the surveillance systems, said they can also take some punishment. Bullets puncturing the blimp's envelope will not cause a catastrophic deflation or explosion, because the helium inside is close to normal air pressure.

"It takes damage very well. Bullet holes will not bring it down," Giauque said. It will fly out of range of most small arms, and any militarily useful blimp would have countermeasures against surface-to-air missiles, he said. However, blimps traditionally are vulnerable to bad weather, particularly high winds.

Blimps can hover for extended periods of time because they need little fuel to maneuver. The blimp over Washington was to be aloft for a 24-hour stretch as part of a demonstration flight, officials said.

The blimp, called an A-170 Lightship, is made by the American Blimp Corporation (search), the only manufacturer in the United States. The military leased the system for the demonstration.

It has been in the region since last week, and is expected to perform additional test runs in the Washington area Thursday and in Maryland on Friday before returning over the weekend to Huntsville, Ala., where the Army's program is based.

Militaries made use of blimps and their rigid counterparts, commonly called zeppelins, during World War I and World War II, primarily for reconnaissance. Airship manufacturers are now proposing futuristic variants capable of hauling heavy cargo over long distances.