SoftBank’s HAPSMobile and Alphabet’s Loon, best known for its internet connection service using balloons, have successfully tested their jointly developed communications payload in the stratosphere on HAPSMobile’s “Sunglider,” a solar-powered unmanned aircraft system (UAS). The test marked the world’s first successful delivery of LTE connectivity from a massive solar-powered drone, flying in the stratosphere.
During the test flight at Spaceport America (SpA) in New Mexico, the drone flew at an altitude of 62,500 feet. (About 19 km) near the stratosphere (66,000 feet or 20 km). The total flight time was 20 hours and 16 minutes, and flew near the stratosphere for 5 hours and 38 minutes, including using the Internet communication system in the stratosphere developed in conjunction with Loon.
According to HAPSMobile, the equipment worked well despite the winds of more than 58 knots (100 km/h) and low temperature, which reached -73 degrees Celsius.
The broadband communication payload enabled a video call between Loon members and AeroVironment team members with smartphones at SpA and HAPSMobile team members in Tokyo. The service link used a 5MHz band of the 700MHz spectrum band (LTE Band28) for this test. This allows the devices to connect directly to the aircraft as if it were a regular telephone tower. In addition to an outdoor environment, the video call test was successful indoors.
The fixed-wing Sunglider is based on a concept called High Altitude Platform Station (HAPS). It is basically an immense wing with a wingspan of 78 meters (256 feet) and is propelled by ten electric motors powered by solar panels covering the surface of the wing and rechargeable battery packs, resulting in zero emissions.
Flying at an altitude of approximately 65,000 feet (20 km) above sea level and above the clouds, the Sunglider can carry payloads weighing as much as 150 pounds and is designed for continuous, extended missions of months without landing. In this region, a single aircraft is capable of providing broadband services over a large area, functioning almost as a “satellite” without the complexity and cost of an orbital flight.
“This successful test represents yet another step to develop a new layer of connectivity based in the stratosphere. It is also an important step in our ongoing strategic partnership with HAPSMobile. By developing technologies to harness the opportunity of the stratosphere, we are making progress toward our shared goal of connecting unconnected and under-connected populations around the world,” said Loon’s CEO Alastair Westgarth.