Satellites are the kings of the communications skies, providing a wealth of voice and data services worldwide. But if last month’s Lighter-Than-Air Technical Committee Convention and Exhibition in Akron, OH, is any indication, they’ll soon get serious competition.Enter stratospheric airships, high-altitude, blimp-shaped mavericks that will beam communication signals far and wide. Compared with satellites, these airships may prove more portable and cheaper to launch and recover, and they could start arriving within five years.
It’s still fairly early days for such sophisticated airships, though, cautions Ron Hochstetler, the convention’s technical chairman. “There’s no cookbook. Only now are we starting to collect the knowledge base we need.”
Stratospheric ships could hover at altitudes of up to 70,000 feet-just above the jet stream-beaming communication signals over a 19,000-square-kilometer area and carrying payloads up to six metric tons. Prime applications for such high-altitude craft include wireless telephony and broadband Internet services.
Many of these ships are designed to run on regenerative fuel systems, which combine solar power during the day and fuel cells at night. Electric motors power slow-turning propellers that help keep the airship platforms stationary.
Charles Lavan, an engineer from Lockheed Martin, says that development of these ships is “beyond the computer modeling phase, but they’re not ready. Stratospheric airships have flown at this altitude. Telecommunications electronics have been tested. The systems have not been integrated and flown together.”
In addition, researchers are still modifying the overall structure of the craft in order to reduce drag as much as possible. Lavan estimates prototypes will be flying in two to three years, with a fully operational stratospheric airship likely in five years.
“There’s also quite a lot of interest from the military in flying sensors and stationary communications platforms,” he adds. “They stay where you put them-that’s the reason for flying at 70,000 feet.”
Military interest in lighter-than-air craft is nothing new. Once a staple for anti-submarine warfare, military blimps are making a comeback-with robotic blimps.
Piloted by a model-plane-like control system, robotic blimps can maintain altitude for long periods. One example is Bosch Aerospace’s unmanned airship, initially designed and tested with the light Volkswagen Beetle engine, now powered by more dependable 80-horsepower Rotax engines.
“The military is interested in an airship that can look for mines in the water,” says James Boschma of Bosch Aerospace. “That’s a very boring and dangerous job for a guy in a helicopter.”
For mine detection, the blimp is programmed with a grid pattern of the flight area of interest. It then scans the ocean surface with lasers. The blimp can also drag the surface with a mine-detonating sled. “In both cases you eliminate the man-in-the-loop,” Bosch says. “It’s a very low-risk approach.”
Other potential military applications include electronic warfare, early warning for sea-skimming missiles, and missile decoys. The robotic blimp can also transmit and receive information to and from ground receivers via satellite-or perhaps, at some future date, via stratospheric airships.
The six-metric-ton lifting capacity of the typical stratospheric airship pales when compared with CargoLifter’s CL 160, a transport airship capable of carrying 160 metric tons. To give it another spin, one CargoLifter payload equals the combined payloads of eight Boeing 727 freighters.
“Nobody has ever built anything like these airships,” says Hochstetler, referring to all manner of lighter-than-air craft. “There are incredible challenges building something more sophisticated than the Goodyear blimp.”