Milestone stratospheric 4G connection for Aalto’s HAPS
March 4, 2025
Airbus subsidiary Aalto has completed successful stratospheric connectivity testing of its ‘Zephyr’ High Altitude Platform Station (HAPS) from high in the skies above Kenya.
Flying continuously at over 60,000 feet, the fixed-wing Zephyr aircraft 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,” explained Aalto. The connectivity testing was performed on behalf of Aalto’s customer Space Compass, and partner and mobile operator NTT DOCOMO; both part of the HAPS Japan consortium that committed to a $100 million investment in Aalto in 2024.
Building on the Zephyr’s first flight of 2025 (which saw the crafts soar in the stratosphere for 13 continuous days, carrying a custom connectivity integration payload), ongoing testing further seeks “to unlock game-changing services from the stratosphere, particularly across connectivity and Earth observation,” explained Aalto CEO Hughes Boulnois.
Aalto had previously indicated that with type approval process to be completed by the end of 2025, the pseudo-satellite’s full operational capability could be online as soon as 2026. HAPS Japan, Aalto, and Airbus Defence and Space will now work to establish 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,” elaborated Shigehiro Hori, co-CEO of Space Compass Corporation. With Space Compass and NTT DOCOMO having “long pioneered the connectivity potential of non-terrestrial networks, the demonstration of connectivity with Aalto’s Zephyr marks a strong start to 2025,” he concluded.
Aalto describes its 100% solar-powered craft as “the most advanced fixed-wing HAPS on the planet” and the only fixed-wing platform to have around-the-lock longevity. During the most recent flight, the company also conducted the performance of the Farnborough-developed connectivity system, including measuring throughput and overall signal quality.
The aircraft was launched from Aalto’s custom-built ‘Aaltoport’ in Kenya, with regulatory operating permissions secured in 2024 following 18 months of regulatory engagement and technical studies facilitated by the Kenya Space Agency and the Kenya Civil Aviation Authority. The most recent connectivity testing was facilitated by the Communications Authority of Kenya.
