DURING THE PREPARATIONS for the 1996 Summer Olympics in Atlanta, local entrepreneur Mike Lawson rounded up a group of investors, pooled $1 million, and bought a one-person, helium-filled airship. His plan: Persuade Olympics officials to rent the craft for security surveillance. “That little sucker would fly about 50 miles per hour,” Lawson recalls.
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On a gloomy day in October 1995, the great nemesis of all airships rose up and dashed his spirit. The remnants of Hurricane Opal blew through Atlanta, ripping Lawson’s lighter-than- air ship from its mooring and carrying it away. No one was hurt and Lawson did retrieve the craft, but it was a total loss. He says he learned an important lesson about airships: “What you put on paper does not necessarily work in the real environment.”
Lawson is now the CEO of a small Columbus, Georgia company, Techsphere Systems International, that stitches sail material into spherical airships, which are maneuvered by swamp-boat propellers. (When on the ground, they can be deflated and folded up, so bad weather is no threat and storage is not a big deal.) Now the Army is funding improvements to make them potential spy platforms.
Techsphere is one of a dozen or so companies that hope to find new applications for a technology that’s been around since the late 1700s, when the Montgolfier brothers in France made the first flights with lighter-than-air craft. Some companies are trying to develop an airship that can hover in the stratosphere for months at a time to spy on terrorist camps or spot truckloads of insurgents or cruise missiles in flight. Others are working on craft that are not quite lighter than air: They would combine the lift of helium with the control capability of heavier-than-air vehicles like airplanes. In the Arctic, where global warming is rendering ice roads unusable, the new vehicles would float drill equipment over the soggiest terrain. All these scenarios envision important new missions for aviation’s historic underachievers.
Balls in the Air
Techsphere Systems was born the day Lawson got a call from Hokan Colting, a Swedish-born hot-air balloonist famous in the airship community for advocating spherical designs. In 1988, Colting founded 21st Century Airships in New Market, Ontario, Canada. In the wake of the 9/11 attacks, Colting persuaded Lawson to set up a company to manufacture and market his spheres for use in patrolling borders and other surveillance applications.
To reduce atmospheric drag, most airships are shaped like cigars. Decades of answering the question “Why spheres?” has made Colting adept at delivering an Airship 101 lesson.
All airships, regardless of shape, get their lift by carrying a lighter-than-air gas, usually helium. As an airship rises, the helium expands, so designers must leave plenty of space in the envelope, or hull. Despite the empty space, airships like the Hindenburg kept their shapes with rigid supports. Modern airships accomplish the same thing by filling the void with air-filled bags, or ballonets, which can be adjusted in size by blowing air in or venting it out. As the craft rises, the helium around the air bags expands, pressing on the bags and causing them to vent their air and shrink; the expanding helium also keeps steady pressure on the ship’s hull.
Helium is tricky stuff, though. It collects at the top of a container like an upside-down puddle, and it has a nasty habit of sliding around like liquid mercury. In an airship shaped like a cigar, elaborate steps have to be taken to keep the helium from accumulating in the nose and pushing that end of the craft up. Because they don’t have noses, Colting’s spherical airships don’t have that problem.
In 2003, Colting sat inside one of his spheres with a pilot and took it to an altitude of 20,453 feet above Gull Lake in Alberta, Canada; it was a record for airships. “It was basically to market that we had a technology that could go to that altitude,” Lawson says. In Iraq and Afghanistan, the current threats to U.S. aircraft are shoulder-fired rockets and rifles, so getting to an altitude above 15,000 feet would put an airship out of harm’s way.
The Navy tested the spheres, and now the Army has awarded a contract to spy equipment manufacturer Sierra Nevada Corporation of Sparks, Nevada, to test a 94-foot-diameter Techsphere prototype, the SA-90. The first flight is scheduled for August.
The Army contract specifies that the SA-90 must demonstrate its usefulness by flying at 18,000 to 20,000 feet for up to 24 hours. Aluminum propellers, 18 feet in diameter, will provide maneuvering. Hovering is easy, but engineers want to see if the sphere can fly at 55 mph to keep up with special operations units on the ground. Of course the spheres will never cut through the air as easily as cigars, so engineers are working on a way to compensate. According to company program manager Rick Osmun, Sierra Nevada hopes to use a 10-foot-diameter prototype to show that a cone-shaped “aero tail” attached to the rear of the SA-90 will reduce drag the way the taper of a sailboat’s stern increases speed.
Though the sphere would evade shoulder-fired rockets, a miniature moon hovering over the battlefield could be an easy target for enemy aircraft. Plans call for camouflaging the spheres “air-superiority gray” like U.S. Air Force fighters.
Today, most airship designers have ambitions to reach the stratosphere, 60,000 feet up, which is about 10 times the current average blimp’s maximum altitude. In addition to being safely above commercial air traffic and the winds of the jetstream, the altitude would give customers the ability to stare continuously at the same patch of ground.