An artistic visualization of the Aalto Zephyr HAPS flight in Kenya. Photo: Aalto

Aalto HAPS has conducted a successful connectivity test on the behalf of customer Space Compass and its partner NTT Docomo. The test saw Aalto conduct a stratospheric connectivity test in Kenya, connecting a 4G mobile device to the Zephyr High Altitude Platform Station (HAPS), the company announced March 3.

Zephyr was equipped with a connectivity payload that made direct communication to a 4G mobile device on the ground and a direct-to-device gateway station in Kenya. Aalto claims this is the first wireless connection achieved by a fixed-wing HAPS flying continuously above 60,000 feet, which included a telephone call from the site in Kenya via Zephyr which was transmitted to the U.K. over a local internet link.

Aalto also conducted different tests to characterize the performance of the connectivity system including measuring throughput and overall signal quality. Aalto said the demonstration was facilitated by a comprehensive regulatory framework in Kenya, where the HAPS vehicle launched and landed.

NTT Docomo, one of Japan’s leading mobile operators, and Space Compass, a joint venture between NTT and SKY Perfect JSAT, are part of the HAPS Japan consortium that committed to a $100 million investment in Aalto in 2024. HAPS Japan, Aalto, and Airbus are establishing a roadmap for commercial HAPS services to begin in Japan from 2026.

“HAPS will play a critical role in Japan’s communications ecosystem, addressing hard-to-reach areas and supporting responses to events such as natural disasters. Space Compass and NTT Docomo have long pioneered the connectivity potential of non-terrestrial networks. The demonstration of connectivity with Aalto’s Zephyr marks a strong start to 2025. This year we will work together to progress commercial timelines for entry- into-service in the Japanese market,” Shigehiro Hori, co-CEO of Space Compass, said in a statement.