Sceye HAPS flies 9,300 miles to Japan in connectivity test

On Aug. 9, a U.S.-built high-altitude platform lifted off from New Mexico. Thirteen days and 9,300 miles across the Pacific later, Sceye’s ST1 entered Japanese airspace for its first Asian mission and began connectivity trials with SoftBank Corp.

The aircraft is a high-altitude platform station, or HAPS: a communications platform flying about 10.3 miles above Earth. Its SceyeCELL payload connected directly with standard mobile devices, so users did not need modified handsets. Using SoftBank’s core network, engineers demonstrated text messaging, voice calls, internet access and video streaming, along with an emergency alert system designed for large-scale disasters.

The test also moved part of the network into the sky. Engineers placed a mobile core network and web server aboard the HAPS, allowing data from a smartphone to be processed on the aircraft and sent back without relying entirely on an internet cloud service. Sceye reported an average round-trip processing time of 68 milliseconds and said latency fell by more than 40% compared with internet-based cloud processing. The aircraft also communicated with drones, testing a shared link for vehicles operating at different altitudes.

Keeping such a platform in the right place is part of the challenge. Sceye reported a station-seeking radius as low as 3.1 miles during the mission, while the aircraft stayed in Japanese-managed airspace for more than seven days. The company says a full-scale platform could cover an area equivalent to roughly 500 terrestrial towers. SoftBank, which invested in Sceye in 2025, is pursuing a communications mix that combines ground, aerial and space-based systems.

So, concretely? In regions where conventional infrastructure faces coverage or deployment limits, the demonstrated combination could give ordinary phones access to messaging, calls, internet services and disaster alerts from a single airborne platform; it could also help connect drones. The limits are visible too: ST1 was still flying back toward the United States over the Pacific when Sceye announced the results. Sceye CEO Mikkel Vestergaard Frandsen said the route showed the performance needed for the stratosphere to become an infrastructure layer, but this remains a field test rather than a deployed service.