Airship of Dreams: Lighter-Than-Air Travel Is Back
With technology borrowed from submarines, a scrappy California company is attempting to resurrect a century-long dream of building huge airships to carry freight—and people—across the skies.
By Kalee Thompson
The Aeroscraft prototype, seen here in its hangar in Tustin, Calif., could herald a new era in airships.
Nathaniel Wood
A few of the engineers crowdedinto the compact glass-and-aluminum cockpit suspended below the hull. At the push of a button, the imposing airship lifted from the concrete, becoming airborne for the first time. It rose 10, 20, and finally 35 feet in the air. Then engineers shifted the ship into descent mode and the Aeroscraft settled back to the floor.
The January test was modest: The engineers called it a first float rather than a first flight. The first test outside the hangar, which occurred in early September, after a necessary Federal Aviation Administration certification was granted, was perhaps less ambitious—the ship remained tethered as it rose about 20 feet in the air. But the vision behind the Aeroscraft is expansive. Its inventor, Kazakhstan-born engineer Igor Pasternak, has dreamed since childhood of building huge airships that would crisscross the skies ferrying freight. He is just one in a long line of believers, stretching back at least as far as the German Count Ferdinand von Zeppelin, who built the first rigid airship in the 1890s. "That idea has been around for over a hundred years," says John Hansman, a professor of aeronautics at Massachusetts Institute of Technology and the director of the university's International Center for Air Transportation. By the mid-20th century, lighter-than-air craft had completed more than 150 trans-Atlantic passenger trips. During World War II American airships carried supplies, bombs, even planes. But then the technology stalled—for good reason, Hansman says. "Once airplanes could make long-range flights and carry a lot of payload, the market quickly shifted."
Today most lighter-than-air ships, or aerostats, are blimps—basically oversize balloons that serve primarily as flying billboards. However, the dream of rigid airships carrying freight refuses to die. In the past decade no fewer than a half-dozen companies have invested millions toward the goal. So far they have little to show for it. But Pasternak and his partners believe they will succeed where others have failed, thanks mainly to the Aeroscraft's innovative buoyancy system. Tony Tether ran the military's DARPA (Defense Advanced Research Projects Agency) program from 2001 to 2009 and now serves on Aeros's advisory board. "It's as big a deal as Kitty Hawk," he says without irony. "This will change the way we deliver cargo, and maybe people, around the world."
When I visited the Tustin hangar in May, the Aeroscraft was skinned like a fish. The flexible composite exterior draped the lower frame, while, above, the complex skeleton and a row of car-size helium tanks were left exposed. The tanks lie at the heart of the Aeroscraft's buoyancy system, which is based on submarine technology. One of the lead engineers, 32-year-old Tim Kenny, walked me through it. Submarines draw in seawater to descend, then pump it out to increase buoyancy and rise toward the surface. The Aeroscraft works the same way, he explained, but it uses air rather than water.
Kenny showed me one of the tanks. Empty, it weighed 500 pounds. Right now, filled with helium at low pressure like a child's balloon, it needed an anchor. I was able to push the huge melon out of place with two fingers. Once it is pumped full of highly compressed helium, Kenny explained, each tank becomes far heavier, like a full propane tank for a backyard grill.
Next Kenny pointed out several large, white expansion bladders. When the airship's helium is compressed inside the tanks, a partial vacuum develops around the bladders, and they fill with air from outside the craft. Buoyancy drops and the ship descends. "Once the tanks release that helium back into the main envelope, the expansion bladders deflate to neutralize the internal pressure of the airship and force the air—the ballast—outside the aircraft," he said. The ship rises.
Conventional airships need to take on ballast (typically water) after delivering their cargo to compensate for the lost weight. They need ground crews and runways, though much shorter ones than an airplane uses. An operating Aeroscraft would require none of that—or any ground infrastructure at all. The machine could fly to a roadless region in the Arctic, settle down on the tundra to unload mining equipment from its huge cargo compartment, and take off again on its own. It could deliver immense wind turbines slung below its hull and hover like a helicopter while bearing loads normally associated with ocean freighters.
The biggest challenge in achieving this capability has been the buoyancy system's weight—the heavy tanks, pumps, and hull structure. "People did not believe you could do all of that and end up with something that could float," Tether says. To solve the problem, Aeros engineers became obsessive ounce-watchers. During my tour Kenny handed me a 6-foot piece of carbon-fiber and aluminum truss, the material that makes up the airship's skeleton. It was disconcertingly light.
Even MIT's Hansman, who remains skeptical of the airship industry's future, believes the technology could work. "It's definitely possible. There are no physics that would prevent them from doing what they want to do. It's just hard—hard technically, in terms of financing and having the persistence to get there."
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