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JP Aerospace’s “high rack”—a rig with cameras fins, and antennas, delivers another bunch of “Pongsat” experiments to near-space. (JP Aerospace)

To Space (Okay, Near-Space) in a Balloon

A little company dreams of replacing rocket power with buoyancy.

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(Continued from page 1)

Powell’s aerospace team is unique. There is no paid staff, no PR department, no lobbyist. The headquarters could fit in one of Lockheed Martin’s utility sheds. “We’re the slowest aerospace program in history,” Powell says. “Think big by thinking small.”

Powell’s office, in an industrial park east of Sacramento, California, looks like a cross between the headquarters of a modest non-profit and the bedroom of a boy in love with flight. A small bookcase holds titles on aerodynamics, polymer dynamics, and electric propulsion, along with Patent It Yourself (Powell has one big patent, for lighter-than-air orbital vehicles, and three others nearing approval) and Sneakier Uses for Everyday Things.

Yet JP Aerospace has managed to solve some of the problems of working in near-space that have stymied large, well-funded organizations. For example, the Air Force spent two decades and $4 billion trying to develop a propeller that would work in the airlessness of space, and still failed. JP Aerospace cracked the challenge in just three months and with only $5,000. The company relied on the aerodynamic distinction between “laminar” and “turbulent flow.” With laminar flow, the layers of the fluid slide past each other like a deck of cards; they don’t separate from the surface. With turbulent flow, they create eddies that ricochet off one another. Because the performance of an airfoil with laminar flow is vastly superior, Powell says, “everyone’s chasing the laminar-flow propeller at 100,000 feet…. A turbulent-flow propeller will work badly at 100,000 feet, but a laminar-flow propeller that’s not doing laminar flow doesn’t work at all.”

Powell’s propellers were put to the test in October 2011, when JP Aerospace’s tandem-balloon vehicle set a new absolute altitude record for an unmanned airship. The previous record was set by the U.S. Army Space and Missile Defense Command, which in 2005 sent its HiSentinel airship to 74,000 feet—14 miles.

JP Aerospace’s Tandem looks like something made with a giant erector set. The 27-foot-long carbon-fiber frame, stocked with cameras, tracking devices, and parachutes, is lifted by a high-altitude balloon on each end and sports two of those turbulent-flow propellers, powered by electric scooter motors. It cost $30,000 to produce—and fully loaded weighs only 60 pounds. On its record flight, it made a smooth liftoff from the Black Rock Desert, then weathered the turbulence of the jetstream as team members radioed signals to fire the propellers in short bursts that would prevent freezing. When the airship passed the Army’s 74,000-foot mark, the ground crew cheered. Video from onboard cameras (on YouTube, search on “World’s Highest Airship”) shows the craft turning, flying forward, and flying in reverse in response to commands sent to the propellers. In the thin air at 95,085 feet, the helium in one of the balloons had expanded so much that the balloon exploded, as planned. Powell sent a command to detach the other, and the vehicle descended under its five parachutes, landing safely.

***

Powell’s ultimate goal is to fly humans into Earth orbit. The three-stage system he envisions for that mission, the Airship to Orbit (ATO), seems far-fetched, even outrageous. A ship light enough to float to an altitude from which it could be accelerated into orbit would first be torn apart by the weather systems in the lower atmosphere, according to Powell. One strong enough to survive them would be too heavy for the final voyage into orbit. His solution is a system with three separate airships. The first stage would be as long as three 737s, the final stage would stretch over a mile, and his middle stage would measure three miles across and permanently hover 26 miles above Earth’s surface. (The immense size of the vehicles serves to maximize lift.) All three airships would employ the same design—multiple gas-filled lifting cells that are contained by an inflated outer fabric shell, strengthened by lightweight carbon-fiber keels.

The first-stage, the V-shaped Atmospheric Ascender, would float up to 140,000 feet. Powell actually built a 175-foot-long version of the Ascender for the Air Force—with disastrous results. The military wanted a reconnaissance vehicle that could fly at 100,000 feet undetected by radar, but disregarded weather warnings and insisted on a demo launch in what became an actual tornado. The vehicle was destroyed.

At 140,000 feet, the Atmospheric Ascender would dock with the second stage, the Dark Sky Station (DSS), named for the sky’s darkness at that altitude. Shaped like a starfish and using buoyancy from the gas-filled cells to stay parked in the thin atmosphere at that altitude, the DSS would serve as airport, warehouse, construction site, and launch site for the third stage: the Orbital Ascender. The Ascender would float up to 200,000 feet, where, in the absence of even minimal atmosphere for lift, it would switch to an alternative energy source for propulsion—Powell thinks a hybrid engine using both chemical and ion propulsion. (Ion engines have been used since the late 1990s to power satellites and exploratory spacecraft.) During this final leg of the journey, which would take about five days, like a leisurely ocean voyage, the Orbital Ascender would gradually accelerate to the speed needed to achieve a stable orbit around Earth. For the return trip, the sequence would be reversed.

Aerospace experts believe that ATO won’t work, arguing that it is physically impossible for Powell’s third-stage airship to reach orbit. Considering weight, mass, velocity, and whatever drag the thin atmosphere at that altitude produces, John Jurist, an adjunct professor in aerospace studies at the University of North Dakota, concludes, “It’s an interesting idea, but when you start actually putting the numbers to it, it just doesn’t appear to work. The acceleration to orbital speed is the killer.”

About Mark Karpel

Mark Karpel takes breaks from his practice as a psychologist to write about people who think big and get carried away. His article on cluster balloonists appeared in the Aug. 2010 issue.

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