A Revolutionary Way to Observe Earth

By Adam Voiland, NASA's Earth Science News Team

Science tends to be a conservative profession. Only rarely are "discoveries" made or paradigms upended. And most researchers spend entire careers working toward incremental advances in understanding rather than dreaming up radical new ways to tackle a problem.

So it's not often that you'll find the word "revolutionary" in the pages of a peer-reviewed scientific journal. Yet, that’s precisely the word that a group of earth scientists and balloon boosters use liberally in a Bulletin of the American Meteorological Society article describing the experimental balloon platform that NASA-funded scientists and engineers have dreamed up.

They’re called StratoSats and, according to advocates like Warren Wiscombe, a senior scientist at NASA's Goddard Space Flight Center who studies Earth's energy budget, the long-duration balloons would cruise on the cusp of space far above airplane traffic. From high in the stratosphere, these super-pressure balloons could collect key data on Earth’s energy budget, climate, magnetic field, and atmospheric water vapor for a tiny fraction of the cost of competing technologies, such as unmanned aerial vehicles or satellites.

Advocates for StratoSats envision hundreds floating in the stratosphere. Constellations of the balloons could be organized to suit the needs of scientists, from “string of pearl” formations that keep a hurricane constantly in view to more or less uniformly distributed formations - as shown in the simulation below (each yellow dot represents a StratoSat).

With the uniform distribution, Wiscombe says, the StratoSats could survey over 99 percent of the atmosphere both vertically and horizontally and cover certain areas near the poles that aren't readily detectable by satellite instruments in sun-synchronous orbits. The StratoSats would be able to ride strong zonal winds that would push them around the Earth every 10 to 20 days.

One nagging drawback of research balloons is that they drift with the winds, which can make it difficult to collect usable data. However, the StratoSats would have a 15-kilometer tether toting a 5-meter wing far below. The wing would function much like the sail of a sailboat, and give scientists the means to keep the balloons on a set course. "Steering a StratoSat is somewhat like steering a cruise ship," Wiscombe said. "You can't make sharp turns, but you can achieve a new course within a few days."

For the last ten years, NASA has been developing ultra-long-duration balloons (ULDB) that aim to study remnants of the early universe. Though some of these stratosphere capable balloons have failed to deploy completely during tests, NASA's Balloon Program, based at Wallops Flight Facility in Virginia, has carried out a successful 54-day flight of a small Super Pressured Balloon.

Meanwhile, full-scale mechanical prototypes of the StratoSat guidance system have already been built and ground-tested. And NASA-funded engineers have successfully flown one-quarter scale balloon guidance systems (below) from blimps, Wiscombe said.

StratoSat boosters may not have too much longer to wait. According to David Pierce, the Chief of NASA's Balloon Program, his team is already well on its way to providing the sort of capabilities that StratoSats would require.

"There is still some engineering development that must be accomplished to fully integrate the small super-pressure balloons with the StratoSat sail, but you can expect the smaller super-pressure balloons to be available within the next year for Earth science missions," he noted. "We are quite confident that StratoSats could do a lot of science at much less cost than orbiting satellites."

 Image Information: In the first image, engineers watch a quarter scale model of a wing-like guidance system that could be used to steer a new type of Earth-observing balloon.  The second image is an illustration of the StratoSat platform. The third is a map that shows the potential formation of a fleet of StratoSats (each yellow dot represents one StratoSat). All three images were published in the Bulletin of the American Meteorological Society without crediting information.