Sceye and SoftBank Corp. have completed a trans-Pacific stratospheric flight of the ST1 high-altitude platform system from New Mexico to Japan, with the mission travelling more than 15,000 km over 13 days and operating at about 16.5 km altitude. The aircraft then began its return to the United States, where it was still en route at the time of the announcement.
The Japan segment included more than seven days of trials over Japanese airspace, where ST1 demonstrated mobile broadband connectivity to unmodified devices through SoftBank’s core network. The mission also verified HAPS-based edge computing and communications with drones, presenting the platform as a potential layer for a wider 3D communications network.
Sceye’s ST1 launched from New Mexico on 9 August 2026 and completed the first flight from the company’s service test programme to Asia. SoftBank described the work as a step towards commercial HAPS deployment in Japan, where it has been exploring pre-commercial stratospheric communications services as part of its broader connectivity strategy.