A U.S.-built high-altitude platform has completed a 9,300 miles journey from New Mexico to Japan. The flight marks Sceye’s first mission in Asia and puts its stratospheric communications system through a major real-world test.
Sceye’s Service Test 1 mission launched from New Mexico on Aug. 9. The HAPS spent 13 days crossing the Pacific before entering Japanese airspace, where it worked with SoftBank Corp. on connectivity trials.
The mission tested whether a platform flying about 10.3 miles above Earth could provide services normally handled by ground infrastructure. It also examined how the aircraft could support drones and process data in the stratosphere.
U.S. platform crosses Pacific
The aircraft traveled more than 9,300 miles before reaching its operating area over Japan. It then remained within Japanese-managed airspace for more than seven days.
Sceye reported a station-seeking radius as low as 3.1 miles during the mission. That capability matters because HAPS platforms must maintain a tight operating area to provide reliable coverage.
The aircraft carried SceyeCELL, the company’s stratospheric telecommunications payload. The system connects directly with standard mobile devices without requiring modified handsets.
SoftBank used its core network to test that connection over Japan. Engineers demonstrated text messaging, voice calls, internet access, and video streaming from the stratospheric platform.
The tests also included emergency communications. Sceye and SoftBank used an emergency alert system designed for large-scale disasters.
Computing moves into stratosphere
The mission also pushed processing beyond the conventional ground-based network. Engineers installed a mobile core network and web server directly aboard the HAPS. Data could therefore move from a smartphone to the platform, undergo processing, and return without relying entirely on an internet cloud service.
That setup produced an average round-trip processing time of 68 milliseconds. Sceye said the result cut latency by more than 40% compared with internet-based cloud processing.
The aircraft also communicated with drones during the mission. That experiment could help connect aircraft operating at different altitudes through a single communications layer.
Sceye CEO Mikkel Vestergaard Frandsen called the flight a defining moment for the company. He said the New Mexico-to-Japan route demonstrated the performance needed to make the stratosphere a viable infrastructure layer.
HAPS targets wider coverage
Sceye sees HAPS as a middle layer between terrestrial networks and satellites. The aircraft can operate far above commercial aviation while staying much closer to Earth than orbital spacecraft.
A full-scale Sceye platform could cover an area equivalent to roughly 500 terrestrial towers, according to the company. That could make the technology useful across regions where conventional infrastructure faces coverage or deployment limits.
The partnership also reflects SoftBank’s interest in combining ground, aerial, and space-based communications. The Japanese operator invested in Sceye in 2025 to support development of its stratospheric infrastructure.
The ST1 aircraft remains in flight and was heading back toward the United States over the Pacific when Sceye announced the results. The mission follows an earlier Sceye endurance flight that traveled more than 6,214 miles from New Mexico toward Brazil.