Sceye’s Pacific flight is the latest milestone in a decades-long effort to build persistent platforms above conventional air traffic. Government backing and regulatory work are gathering around the technology but as always, commercial success will depend on the services it can sustain.
In September of this year, Sceye announced that its Service Test 1 platform had returned to the United States after a month-long journey to Japan and back. The company reported nearly 30,000 km of travel, more than seven days in Japanese-managed airspace and successful communications trials with SoftBank. It described operations at 16.5 to 17 km altitude and a station-seeking radius as small as 5 km during part of the mission. The vehicle subsequently underwent additional testing and a planned termination and descent near Moriarty, New Mexico (Sceye, 9 September 2026).
For anyone who remembers the broad, slender wings of Airbus’s Zephyr, this will reignite interest in high-altitude platform systems (or HAPS, because if it doesn’t have an acronym, is it real?), which are aircraft and lighter-than-air vehicles intended to carry useful payloads for extended periods in the stratosphere.
The attraction for Earth observation is persistence. Where a customer needs to follow a particular region through a developing event, an platform overhead will provide measurements between satellite passes and reduce the need for repeated aircraft sorties. Turning that proposition into a dependable service is the challenge that has occupied developers for decades.
One ambition, several kinds of aircraft
Airbus’ Zephyr uses solar-powered wings and batteries to sustain flight (crucially through the night) whilst Sceye follows a lighter-than-air approach, using buoyancy to remain aloft. Alphabet’s former Loon programme used balloons that changed altitude to exploit winds travelling in different directions. These approaches have different implications for payload capacity, energy use and control over location.
The terminology also needs care. The International Telecommunication Union’s formal definition concerns a radio station on an object at 20–50 km altitude, maintaining a nominal position relative to Earth. Industry uses HAPS more broadly, including for the lower-altitude operations reported by Sceye. A label is therefore less informative than the actual flight altitude, payload and operating conditions.
A history of progress and difficult lessons
The foundations long predate today’s interest in persistent monitoring. NASA’s Environmental Research Aircraft and Sensor Technology programme supported solar aircraft including Pathfinder and Helios during the 1990s and early 2000s. Helios reached 96,863 feet in 2001, then was lost during a test flight in 2003. NASA subsequently identified an inability to predict its increased sensitivity to atmospheric disturbances after configuration changes. Lightweight structures and ambitious endurance targets demanded a deep understanding of how the whole aircraft behaved.
Britain developed a prominent strand of this technology through Zephyr. Airbus acquired the programme from QinetiQ in 2013 and its commercial development now sits within AALTO. The programme’s history records an almost 26-day flight in 2018 and more than 64 days in 2022. These milestones progressively extended the evidence for sustained solar-powered flight.
Another British programme, BAE Systems subsidiary Prismatic’s PHASA-35, illustrates the importance of repeatability. In December 2024, BAE reported a 24-hour flight above 66,000 feet followed by a landing in a ‘serviceable condition‘ with the aircraft ready to fly again two days later. Recovery, inspection and redeployment matter to a future operator alongside the duration of any one flight.
Loon demonstrated stratospheric connectivity was possible but closed in 2021 because commercial viability was taking longer and proving riskier than expected.
What Sceye’s flight means for EO
The recent Pacific mission was principally a communications demonstration. SoftBank reports tests involving smartphones, video services and emergency messaging including cooperation with the Japan Coast Guard. Its announcement targets commercialisation from 2027 onwards which represents meaningful progress towards an operational service, while remaining distinct from proof of a mature EO offering.
Sceye identifies wildfire detection, maritime awareness and industrial emissions monitoring as observation applications. These make sense as potential markets for persistent sensing as fires develop, vessels move and emissions vary over time. However, the usefulness of a particular product depends on the sensor, its coverage and the quality of the resulting measurements. A platform’s endurance does not establish a methane detection threshold or guarantee that a vessel can be identified.
Being above much of the weather also means that clouds are in the line of sight to the ground and obscure surface information in optical imagery, making payload choice fundamental to the service (Read the ESA explanation of cloud masking).
There is already a relevant European development. ESA lists HAPSEYE, led by ICEYE Spain, as an InCubed-supported project to develop a solar-powered platform carrying synthetic aperture radar. Its intended role is to complement ICEYE’s satellite constellation with persistent observation and rapid delivery during disasters and other critical events. The 30-month activity is listed from September 2025 and it is development work not evidence that a commercial HAPS radar service is already available.
Governments are dipping their toes
In 2016, the UK Ministry of Defence announced a third Zephyr-S as part of a £13 million contract, supporting work on future intelligence capabilities. And whilst this is historical evidence of government procurement, there a little or no evidence of newly available funding in the UK for HAPS.
The US government’s SBIR database records a 2025 NASA Phase II award of $899,994 to Spectral Sciences for a hyperspectral imaging system combining its instrument with Sceye’s platform. The proposed work includes a 14-day demonstration and the recorded award period runs to August 2027. This connects HAPS development to NASA’s Surface Biology and Geology measurement needs rather than relying solely on commercial enthusiasm.
Japan provides further evidence of coordinated interest. NICT lists a five-year HAPS communications research programme covering fiscal years 2023–2027. Separately, a Japanese consortium including NTT DOCOMO, Space Compass, Mizuho Bank and the Development Bank of Japan committed $100 million to AALTO in 2024.
These examples establish that governments and public institutions recognise the technology but of course, they do not establish a general subsidy for HAPS operators or guarantee long-term customer demand.
Who governs the airspace?
The stratosphere is not an unregulated space simply because it lies above most airline traffic: the ICAO reiterates that states have sovereignty over the airspace above their territory. Its guidance also explains that unmanned aircraft are subject to the Chicago Convention’s provisions on pilotless aircraft including the requirement for special authorisation when flying without a pilot over another contracting state’s territory. Calling a vehicle a pseudo-satellite does not give it satellite-style freedom of overflight.
So there is a task to adapt aviation oversight to unusual vehicles and operating patterns. A HAPS mission must climb and descend through other traffic, operate safely during communications or propulsion failures and coordinate movements across boundaries. Where an air traffic service manages an oceanic region, that responsibility should not be confused with sovereignty over the ocean beneath it.
Europe is working on these questions now. EASA’s January 2026 guidance says existing higher-airspace activities are handled through national or case-by-case arrangements but there is no dedicated harmonised European framework yet. Under a European Commission mandate, EASA is developing draft rules during 2024–2027 and uploaded new guidance on innovation testing frameworks on 4 September 2026. This is preparation for regulation, rather than a completed regime already governing every HAPS mission.
EUROCONTROL’s ECHO 2 project addresses the operational side, including HAPS integration, cross-border coordination and contingency procedures. Its participants include NATS and AALTO giving the work a direct UK connection. The UK CAA has also explicitly considered higher-airspace operations in its airspace research.
Radio permissions form another layer. ITU arrangements address spectrum use and interference protection whilst flight authorisation addresses aviation safety and airspace access. A successful telecommunications demonstration does not by itself settle the permissions needed for routine operations elsewhere.
What should the industry watch next?
For BARSC’s readers, the most useful next milestones will be evidence of repeatable service delivery. How long a platform can observe its assigned area, how much useful data it delivers and how reliably a replacement can take over. Seasonal performance, launch conditions, payload power requirements and maintenance will all influence the service a customer can actually buy.
A plausible future is a combination of platforms. Satellites provide broad coverage and identify events that need attention whilst a dedicated HAPS could sustain regional observation leaving aircraft, drones and ground teams to supply targeted detail and verification.
The opportunity for remote sensing companies extends to compact sensors, calibration, data processing and integration with existing customer systems.
Sceye’s journey adds evidence that stratospheric platforms can undertake complex international missions but the next test is whether HAPS operators can make useful observation routine enough, reliable enough and affordable enough for customers to build into their daily work.
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