Balloon-based transceivers for long-distance medical telemetry communications? It sounds like whimsical science fiction, but Space Data of Chandler, Ariz., has found a way to make it work.

The company has come up with a business model that combines high-flying weather balloons and reusable, parachute-equipped radio transceivers. These transceivers can relay radio communications across a circular footprint 400 miles across — for a very low cost.

This combination of wide coverage and low cost has convinced the Navajo Nation to adopt Space Data's platform for a diabetes telemedicine application. Using consumer wireless devices, diabetics in the Navajo Nation will transmit their blood-sugar readings to remotely located physicians in real time. Given the scarcity of medical resources in their territory — doctors are often 100 miles away — wirelessly monitoring these diabetics is a cost-effective way to deliver needed treatment.

The Navajo Nation is the largest Native American reservation in the United States. It covers 27,000 square miles in Arizona, New Mexico and Utah, and is home to 180,462 Navajos.

Unfortunately, the Navajo Nation's location — where the four corners of Arizona, Colorado, Utah and New Mexico meet — is in the Great Desert Basin. Not only is the climate hot and dry (except in winter, when it snows), but the land is unsuited to raising anything beyond herds of sheep, goats and a limited number of cattle. Add an economically depressed population scattered among small towns and vast open spaces, and providing quality medical care is a serious challenge.

“We don't have the same level of infrastructure as the rest of the country,” said Dr. Peterson Zah, former president of the Navajo Nation and now an advisor to the president of Arizona State University on American Indian affairs. “We do have some landline and cellular coverage in our nation, but it is far from complete. Meanwhile, many of our people live in rural areas without electricity, and many of the roads that serve them are impassable in bad weather. So jumping in the car to see the doctor is not feasible on a regular basis.”

Diabetes is a real problem for the Navajos. According to government research, 20% of Navajos ages 20 and older have Type-2 diabetes. This is why effective blood sugar monitoring is a priority for the Navajo Nation, and why its tribal government decided to look at Space Data's technology.

“The Space Data approach provides two-way connectivity for our people wherever they are; even in deep canyons where earth-based radio systems can't penetrate,” Zah said. “Meanwhile, the fact that the system allows us to use consumer-grade wireless devices — which can be charged using solar energy if need be — is a practical cost-saver.”

Space Data is a pioneer in near-space communications — the broadcast area above airplanes but below satellites in orbit. “Our airborne equipment occupies the space between 65,000 feet and 100,000 feet altitude,” said Jerry Knoblach, Space Data's chairman and CEO. “This is a place safely above the path of airliners and far below spacecraft. It is unused high ground that can provide effective wide-area radio communications.”

Space Data's transceivers serve a number of markets. For instance, its SkySite balloon-borne platforms have been providing telemetry to southwestern U.S. oil and gas companies for the last five years. Meanwhile, the company's StarFighter platform provides a similar wide-area service to military units.

For the Navajo Nations project, which is in the process of being implemented, Space Data's plan is to launch 900 MHz radio transceivers on weather balloons.

“900 MHz qualifies as the Narrowband PCS spectrum,” Knoblach said. “Space Data is currently the largest NPCS license holder in the country. This spectrum can be used for broadband communications, such as … voice and data traffic for first responders.”

Each NPCS transceiver will be loaded onto a platform that includes batteries, antennas, a parachute and a radio-controlled release device. Because the entire package weighs six pounds, it does not require FAA approval to fly. Like SkySite, the Navajo Nations platforms will operate at low data rates of just 6.4 kb/s. This is sufficient for two-way data communications.

“We attach each platform to a weather balloon,” Knoblach said. “At launch, the balloon measures 5 feet in diameter. At 100,000 feet, it expands to 30 feet in diameter.” At this height — which is 18.9 miles above Earth — the view down is breathtaking (as balloon-shot photos taken by Space Data clearly show). But what is really impressive is the coverage: 200 miles in all directions from the transceiver platform.

“What our balloons are is the world's tallest transmission towers — without the towers,” Knoblach quipped. “That's what balloon-based transceivers can provide, at a very reasonable cost.”

Of course, batteries can only run for so long. “After 24 hours, we launch a second balloon to take over duties from the first,” Knoblach said. “Once it is on station, we signal the first platform to detach from the balloon and parachute to earth. It is recovered upon landing, checked out and fitted with new batteries. When the time comes, it is returned to service on another balloon.”

“We are able to provide satellite-style communications at a cost that is a thousand times less,” he added. “We can adjust and upgrade our equipment as need be, since we get to see it every 24 hours. That's not possible with satellites. Once they're up there, there's nothing you can do, save perhaps a software fix.”

What about the balloons that are left without their 6-pound payloads? They gain altitude until they burst; usually into tiny fragments that rain down to Earth without any serious environmental impact.

As mentioned earlier, the data that is relayed by the Space Data transceivers is sent via consumer-graded wireless devices. The patients take their readings, then text them to their doctors. The data is then stored in the doctors' monitoring programs. Any anomalies in the readings — too high, too low, or changing too dramatically and often — are sent to the physicians as alerts. Patients also can send e-mails to their community health workers.

For the Navajos, the Space Data platform is an affordable, practical answer to their diabetic telemedicine needs. “This system is easy to use and able to operate in the remotest of locations,” Zah said. “It works well for our population; even those elders who are not familiar with mainstream technology.”

“Near space communications is a fast, affordable and redundant alternative to satellites and towers,” Knoblach noted. “For the Navajo Nation, balloon-based transceivers make the difference between having access to telemedicine or not. It's that simple.”

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