4 New 'Blimp' Designs Bring Return of the Airship Read more: 4 New 'Blimp' Designs Bring Return of the Airship - Popular Mechanics

Always on the verge of a seeming comeback, airships are back in the spotlight, touting new technologies. The Defense Advanced Research Project Agency recently announced funding for an innovative, ballast-free airship technology created by Aeros Aeronautical Systems, based outside Los Angeles. The Aeroscraft ML866's potentially revolutionary Control of Static Heaviness system compresses and decompresses helium in the 210-ft.-long envelope, changing this proposed sky yacht's buoyancy during takeoff and landings, Aeros says. It hopes to end the program with a test flight demonstrating the system. Other companies are planning their own first flights within the next few years. Each has a design that it promises will launch a new era of lighter-than-air transportation.

HAA

Description: To blanket hundreds of miles with high-resolution radar, the 450-ft.-long, unmanned High Altitude Airship will use old-fashioned lifting gas to ascend. A top-mounted solar array may enable this massive radar platform to stay aloft for up to a month.
Designer: Lockheed Martin
Operational Alt.: Up to 60,000 ft.
Speed: 28 mph (cruising)
Progress: The airship's radar system is still being developed, but Lockheed is scheduled to fly a full-size prototype of the ship by the end of 2009. The Missile Defense Agency is a potential user.
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SA-60

Description: This unmanned, 62-ft.-dia. diesel/electric hybrid broke the world airship altitude record in 2003, reaching 20,000 ft. Designed for scouting and surveillance, the SA-60 can fly autonomously. Its round design gives it more low-speed maneuverability.
Designer: Techsphere Systems International
Operational Alt.: Up to 10,000 ft.
Speed: 35 mph (cruising)
Progress: With no major deals announced, Techsphere is putting its best blimp forward, with a higher-altitude followup to the SA-60--the SA-68--scheduled to fly this year.

Skycat-20

Description: The cargo-hauling SkyCat-20 features retractable hover-cushion engines that allow for vertical takeoffs and landings and can also be reversed, eliminating the need for a ground crew or handling equipment. Variants could include firefighting blimps.
Designer: World Skycat
Operational Alt.: Up to 10,000 ft.
Speed: 97 mph (maximum)
Progress: World SkyCat originally planned a first flight for 2002. The updated schedule calls for a SkyCat-20 world tour by the end of this year, and production models in early 2009