On May 2, AALTO announced that its Zephyr High Altitude Platform System (HAPS) has set a new stratospheric flight record, with one of its aircraft flying continuously for 67 days. The flight was jointly managed by the stratospheric operations center located in Farnborough, Hampshire, UK, and a ground control station in the United States, operating in three shifts daily.AALTO stated that the flight mission took off from its AALTOport operational base in Kenya on February 20, maintaining a continuous flight in the stratosphere for 67 days, 6 hours, and 52 minutes. The flight was ultimately terminated early on April 28, 2025, over a designated aviation protection area in the Indian Ocean due to an undisclosed issue, forcing operators to abandon the aircraft in the Indian Ocean, resulting in the loss of one Zephyr aircraft.AALTO’s Chief Technology Officer Pierre-Anthony Aubrog said that the aircraft had “a lot” of remaining battery power at the end of the flight. “This was our first time conducting a 12-hour night flight,” he noted, as previous flights had been conducted closer to the equator. “We are very satisfied with the degradation of the aircraft and batteries, which was less than expected,” he added.After its launch, Zephyr conducted payload connection tests before flying over Australian airspace. During this flight, Zephyr traversed seven different flight information regions, the most ever recorded for HAPS. The aircraft also crossed the Intertropical Convergence Zone (ITCZ) twice, demonstrating Zephyr’s stability and performance amid weather changes in the Northern and Southern Hemispheres. The ITCZ is a low-pressure area near the Earth’s equator where the trade winds from the Northern and Southern Hemispheres converge, leading to frequent thunderstorms and heavy rainfall.“We challenged the aircraft’s limits in terms of temperature, vibration, and more,” he pointed out. “This is a very important step for us to prepare for the commercialization of [the project] next year.”AALTO stated that this controlled descent occurred within a pre-planned “designated aviation safety zone.” This demonstrated the safety of the aircraft, as AALTO has procedures and technologies in place for implementing a safe termination even in such events.AALTO indicated that the company will soon conduct further flight tests of Zephyr to provide demonstrations for important stakeholders and partners in Japan. Next year, AALTO plans to launch commercial services for Zephyr in the country through collaboration with Japanese mobile communications service providers NTT Docomo and Space Compass. AALTO plans to conduct multiple flights from Kenya in 2025, with plans to deploy two aircraft simultaneously in the stratosphere.
At the same time,AALTO stated that the company is seeing increased interest from potential military and commercial customers.“In Europe, the United States, and other potential defense users, some want to move very quickly, possibly hoping to fly in the summer. I believe we can support them. Many countries are now focusing on High Altitude Platforms (HAPS), especially us, as they are not relying on technologies controlled by Europe or sovereign nations, such as Starlink, which is advantageous for us. Telecommunications operators, including those in the Asia-Pacific region, are looking for ways to expand direct-to-device network coverage. When people see High Altitude Platforms (HAPS), they often focus solely on the aircraft and its technology, overlooking the end-to-end systems required to manage that system—this is precisely what AALTO is currently demonstrating; it is not just an aircraft.”