Altaeros’ ST-Flex is a rapidly deployable autonomous aerostat

HOKKAIDO SPACEPORT, TAIKI TOWN, HOKKAIDO, JAPAN (JUNE 22, 2022): , SoftBank Corp. (“SoftBank”), Japan’s leading mobile carrier, completed initial testing of Altaeros’ ST-Flex™ autonomous aerostat. Operational and telecom tests were performed at Hokkaido Spaceport, Taiki Town, Hokkaido, Japan. Learn more about ST-Flex:

SoftBank and Altaeros first launched the ST-Flex on May 2, 2022 and performed evaluation tests through May. ST-Flex carried SoftBank’s base station system, which was equipped with its proprietary cylindrical antenna that realizes communication area footprint fixation, to a height of 816 feet (249m), where it was connected to their ground equipment via optical fiber and power conductors embedded in the tethers. From SoftBank’s announcement: “The newly developed high-altitude tethered aerostat base station system was operable at higher altitudes and carried heavier communication payloads, and it also achieved wider area network coverage with greater communication stability during the trial Details and additional results from SoftBank’s telecom testing can be found here:


ST-Flex Launches in Hokkaido

Aerostat Autopilot™, Altaeros’ proprietary autonomous control system, eliminates on-site crew for daily operations and ensures the highest level of reliability, making ST-Flex the most cost-effective aerostat solution in its class. During the test program, the ST-Flex excelled in highly variable weather conditions, including gale-force wind. Altaeros’ three tether autonomous controls create stability in the aerostat and control pitch, roll, and yaw to keep the aerostat steady even in varying weather conditions. The autonomous features provide a level of performance and flexibility unparalleled amongst commercial unmanned aerial vehicles (UAVs). Watch highlights here:

“We are incredibly excited to have completed the first international launch of the ST-Flex,” said Altaeros CEO, Ben Glass. “Successful testing of SoftBank’s Footprint Fixation Technology on the ST-Flex is a huge milestone which will further the development and effectiveness of many aerial telecommunications platforms to help bring critical services around the world.” 

About SoftBank Corp.

Guided by the SoftBank Group’s corporate philosophy, “Information Revolution – Happiness for everyone,” SoftBank Corp. (TOKYO: 9434) provides telecommunications services and combines them with advanced technologies to develop and operate new businesses in Japan and globally. In the year ended March 2022, SoftBank Corp. registered 5.7 trillion yen of revenue, 985.7 billion of operating income, and had 319 group companies (245 subsidiaries and 74 affiliates), both in Japan and abroad. SoftBank Corp. has 57 million mobile and broadband subscribers in Japan, and through its group companies Yahoo Japan Corporation, PayPay Corporation and LINE Corporation, 86 million online media users, 46 million smartphone payment users and 92 million communication app users, respectively (as of May 11, 2022). With this strong business foundation and compelling number of customer touchpoints, SoftBank Corp. is expanding into non-telecom fields in line with its “Beyond Carrier” growth strategy while further growing its telecom business. Also, by fully harnessing the power of 5G, AI, IoT, Digital Twin, Non-Terrestrial Network (NTN) solutions, including High Altitude Platform Station (HAPS)-based stratospheric telecommunications, and other key technologies, SoftBank Corp. aims to realize the “Implementation of Digitalization into Society.” In recognition of its ESG initiatives, SoftBank Corp. was selected for inclusion in the Dow Jones Sustainability Indices, FTSE4Good, 2022 Constituent MSCI Japan ESG Select Leaders Index and other leading global ESG investments indices. To learn more, please visit


About Altaeros: Altaeros’ mission is to connect people, machines, and data, no matter where they happen to be located. We leverage cutting edge autonomy and advanced aerospace technology to build the most effective aerial platform available. Our SuperTowers are used to deliver high speed, low-cost broadband to underserved communities, build IoT networks to monitor industrial sites or crop health, provide an elevated vantage point for first responders fighting wildfires or other natural disasters, and any number of other applications. Altaeros is headquartered in Greater Boston, with production and test facilities in southern New Hampshire. Altaeros is backed by SoftBank Group, SPARX, SKK, Safar Partners and others.
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Elise Gianattasio