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."
The Aeroscraft uses a buoyancy system called COSH, for Control of Static Heaviness, which is inspired by submarine technology. The system eliminates the need for runways and ground crews. That could make this airship ideally suited for moving heavy cargo to remote locations.
Aeros's first planned production model will have 18 helium tanks (1). To increase lift, the pilot releases helium, which is much lighter than air, from the tanks into the large envelope (2) that makes up most of the volume of the ship (cargo hold not shown). This applies pressure to the four large air bladders (3) located along the sides of the Aeroscraft.
As the bladders are squeezed, much of this air is expelled to the outside. The overall density of the Aeroscraft decreases and the ship rises. To descend, the pilot reverses the process. Three powerful compressors (not shown) force the helium from the envelope back into the storage tanks. A partial vacuum develops inside the envelope and the airbags expand, pulling in dense air from outside the ship. The Aeroscraft sinks. (The transfer of air is assisted by a system of fans and valves.) In flight, the Aeroscraft's shape helps it de-velop some additional lift, but this is not needed for takeoff and maneuvering.
Pasternak was born in what is today Kazakhstan and grew up in Ukraine, the son of Soviet civil engineers. After graduating in the 1980s with an advanced engineering degree, he started building aerostats for advertising and environmental monitoring, as Mikhail Gorbachev's perestroika initiative got started. By the early 1990s he had 60 employees and was selling and leasing 3000 oversize, unmanned balloons throughout the Soviet bloc and beyond. Everything, he says, came from experimentation. "I was creating technology. You don't have textbooks, you don't have examples."
Then the Soviet Union collapsed. "There was only one decision," Pasternak said. "To build something like the Aeroscraft, you need to be in America." He emigrated in 1994 and spent his first few months in New York. One day he saw then President Clinton on the news, announcing the closure of California's Castle Air Force Base, a former B-52 testing site. By the next year Pasternak and a handful of employees with heavy accents were building balloons in a facility still redolent of the Cold War. "It was a bunch of Russians and B-52s—same hangar!"
Pasternak built manned airships for advertisers—the 1996 Atlanta Olympics, MasterCard, tourism boards. After Sept. 11 the in-sky advertising market dried up, but the Department of Defense started looking into aerostats. Pasternak and Lockheed Martin both secured multimillion-dollar design-feasibility grants for a program called Walrus HULA (Hybrid Ultra Large Aircraft), which sought to develop an airship that could cover 12,000 nautical miles in seven days, with a payload capability of at least 450 tons. The military didn't pursue Walrus, but it later initiated a program called the Long Endurance Multi-Intelligence Vehicle (LEMV), which funded a Northrop Grumman design before being canceled in early 2013. During this period of on-and-off military spending on airships, Pasternak managed to acquire $35 million in government money to build his Aeroscraft, while assembling a scrappy team of engineers.
"You need to know how to hold a screwdriver," he told me—not just how to run computer modeling programs. "It's mechanics." As a second requirement, Pasternak hires only employees who have virtually no experience with airships. "We're not hiring anyone from mainstream industry," Pasternak said. "We are grabbing the people who don't already know what is impossible."
The Aeroscraft in Pasternak's hangar is the biggest rigid airship built in the United States since the 1940s. But it's tiny compared with the transport vehicle that Pasternak envisions. He sees, first, a fleet of 555-foot-long airships that he says will carry 66 tons in the cargo hold. Eventually Pasternak plans to launch a version that could haul 250 tons. It would be 770 feet long, three times the length of a Boeing 747.
Bigger is better is a key tenet of airship transport. It all comes down to something called the square-cube law, explains aerospace engineer Robert Boyd, head of the hybrid airship program at Lockheed Martin. "If you take an airship and you double its length, that makes the surface area go up by roughly four; that's the square," Boyd explains. "And it makes the volume go up by roughly eight, which is the cube." The square is associated with the bad things—drag and weight. The cube is what's good: A bigger volume of helium means more lift. "So, as you get larger, the good things grow much faster than the bad things," Boyd says, and that brings a huge benefit in efficiency.
Lockheed Martin's own prototype, developed independently of any government contract, is a 120-foot airship called the P-791. The company's largest proposed version would be 800 or 900 feet long and haul up to 500 tons. Large airships like that could transport cargo far more cheaply than fixed-wing planes, according to a study prepared a decade ago by the Pentagon's U.S. Transportation Command. Airships would ultimately cost about a third as much to build as a 747 and would use a third as much fuel. Even airships that require a ground crew and runway are less infrastructure-intensive than large fixed-wing aircraft.
Of course, airships have weaknesses as well. The Aeroscraft's cruising speed will be about 115 mph, versus more than 500 mph for an airplane such as the 747. And bad weather presents unique challenges. An airship of any design is "probably less sensitive [than airplanes] to things like turbulence because it's so big—kind of like an ocean liner as compared with a rowboat," MIT's Hansman says. "But it's got a much more difficult time dealing with wind and turbulence on takeoff and landing." The full-scale Aeroscraft is designed to operate in winds up to 40 knots, but it can't outrun bad weather the way an airplane often can—the operators would have to rely on weather forecasts and conservative planning. That would be a challenge in the Arctic, where violent storms can last for days.
There are business challenges, as well. After the P-791's successful test flight, there was talk of developing larger versions of the ship to carry cargo, but, so far, the prototype has flown only a handful of times. Today it sits, waiting for a suitor, in a hangar at Lockheed Martin's Skunk Works facility in Palmdale, Calif. "Nobody's really built a cargo aircraft in the history of aviation," Boyd says. "What they build are people-carrying aircraft, and then they convert them to cargo." That's how Lockheed's workhorse C-130 and C-5 cargo planes got started. Now, however, airship companies are trying to convince freight carriers to take the risk.
Days after I talked with Pasternak in his Montebello office, he was on a plane. In the past few months he's been peddling his Aeroscraft everywhere from the Paris Air Show to transportation conferences in Washington, D.C., Munich, and Anchorage, Alaska. He is seeking private investors to help fund two full-size, 66-ton-payload airships; he would then spin off a separate company to lease them to private industry, just as he did with his early aerostats in the Soviet Union. The entire effort had a setback in October, when a 25-foot section of the hangar roof collapsed, damaging the prototype and delaying further test flights. Still, Pasternak predicts that by 2020 he'll have an initial fleet of 24 airships.
"What we're trying to do, we're trying to change the world completely," he says. As I listen to Pasternak, at once so eager and so patient, I can't help but ask the obvious question: People have been talking about cargo airships for more than a century. Why now? "That is very simple," he answers. "We are ready."