DSEI 2025: How PHASA-35 Drone Brings a New Dimension to Military and Civil Operations in the Stratosphere
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At the DSEI 2025 exhibition, BAE Systems and its subsidiary Prismatic Ltd present the PHASA-35 system, a solar-powered uncrewed aircraft designed to operate in the stratosphere. Conceived as a high-altitude pseudo-satellite, it is intended as an alternative to traditional means of communication and surveillance, whether through satellites or conventional aircraft. Its purpose is to provide a platform capable of remaining airborne for several consecutive months without refueling, with limited operational costs and greater flexibility compared to currently available systems.Follow Army Recognition on Google News at this link
PHASA-35 can support maritime monitoring, border protection, and secure data transmission for armed forces (Picture source: Army Recognition)
PHASA-35, an acronym for Persistent High Altitude Solar Aircraft, conducted its first flight trials in 2020 after being designed and assembled in less than two years. In 2023 and again in 2024, it reached altitudes above 66,000 feet during test campaigns before landing without incident. With a wingspan of 35 meters, comparable to that of an Airbus A320, and a weight of 150 kilograms, similar to a motorcycle, the aircraft relies on a composite structure and solar panels extending across its wings. These supply rechargeable batteries that maintain flight during night operations. This configuration allows the platform to operate in the upper layers of the atmosphere, well beyond commercial air traffic.
The system offers operational advantages compared to other platforms. Unlike satellites, which require costly launches and cannot be retrieved once deployed, PHASA-35 can be launched from conventional runways, recovered, modified, and reused, reducing both cost and logistical complexity. Unlike conventional aircraft and drones, which depend on refueling, ground crews, and limited endurance, PHASA-35 can maintain position over a designated area for several months without continuous human management. This persistence enables surveillance or communications coverage that no current airborne platform can match.
The range of potential uses is wide, extending across civil and military applications. PHASA-35 can support maritime monitoring, border protection, and secure data transmission for armed forces. It can also provide communication services such as mobile coverage or internet access in remote or underserved regions. In addition, the system may be deployed as a relay during disaster relief operations, when ground infrastructure is damaged, or as a platform for environmental and climate monitoring. Its modular payload design allows integration of ISR sensors, imaging systems, or communications equipment, with the possibility to adapt and update these payloads as technology progresses.
The program is integrated within FalconWorks, BAE Systems’ research and development center dedicated to advanced and agile aerospace solutions. Its lightweight structure and energy autonomy reduce logistical requirements and make long-term deployments feasible. The absence of the need for orbital launches, combined with the option of retrieval and reuse, positions PHASA-35 as a practical complement to satellite constellations while providing more persistence and coverage than conventional aerial platforms. This makes it a potential enabler for extending communications networks, including the development of 5G infrastructure.
PHASA-35 illustrates the effort of BAE Systems and Prismatic Ltd to introduce new aerial systems that occupy the operational space between satellites and conventional aircraft. Its presentation at DSEI 2025 underlines the growing demand for persistent, flexible, and cost-effective surveillance and communications solutions. The deployment of this technology points to the wider proliferation of stratospheric aircraft, a development that could reshape the balance between air and space platforms in defense and security.
{loadposition bannertop}
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At the DSEI 2025 exhibition, BAE Systems and its subsidiary Prismatic Ltd present the PHASA-35 system, a solar-powered uncrewed aircraft designed to operate in the stratosphere. Conceived as a high-altitude pseudo-satellite, it is intended as an alternative to traditional means of communication and surveillance, whether through satellites or conventional aircraft. Its purpose is to provide a platform capable of remaining airborne for several consecutive months without refueling, with limited operational costs and greater flexibility compared to currently available systems.
Follow Army Recognition on Google News at this link
PHASA-35 can support maritime monitoring, border protection, and secure data transmission for armed forces (Picture source: Army Recognition)
PHASA-35, an acronym for Persistent High Altitude Solar Aircraft, conducted its first flight trials in 2020 after being designed and assembled in less than two years. In 2023 and again in 2024, it reached altitudes above 66,000 feet during test campaigns before landing without incident. With a wingspan of 35 meters, comparable to that of an Airbus A320, and a weight of 150 kilograms, similar to a motorcycle, the aircraft relies on a composite structure and solar panels extending across its wings. These supply rechargeable batteries that maintain flight during night operations. This configuration allows the platform to operate in the upper layers of the atmosphere, well beyond commercial air traffic.
The system offers operational advantages compared to other platforms. Unlike satellites, which require costly launches and cannot be retrieved once deployed, PHASA-35 can be launched from conventional runways, recovered, modified, and reused, reducing both cost and logistical complexity. Unlike conventional aircraft and drones, which depend on refueling, ground crews, and limited endurance, PHASA-35 can maintain position over a designated area for several months without continuous human management. This persistence enables surveillance or communications coverage that no current airborne platform can match.
The range of potential uses is wide, extending across civil and military applications. PHASA-35 can support maritime monitoring, border protection, and secure data transmission for armed forces. It can also provide communication services such as mobile coverage or internet access in remote or underserved regions. In addition, the system may be deployed as a relay during disaster relief operations, when ground infrastructure is damaged, or as a platform for environmental and climate monitoring. Its modular payload design allows integration of ISR sensors, imaging systems, or communications equipment, with the possibility to adapt and update these payloads as technology progresses.
The program is integrated within FalconWorks, BAE Systems’ research and development center dedicated to advanced and agile aerospace solutions. Its lightweight structure and energy autonomy reduce logistical requirements and make long-term deployments feasible. The absence of the need for orbital launches, combined with the option of retrieval and reuse, positions PHASA-35 as a practical complement to satellite constellations while providing more persistence and coverage than conventional aerial platforms. This makes it a potential enabler for extending communications networks, including the development of 5G infrastructure.
PHASA-35 illustrates the effort of BAE Systems and Prismatic Ltd to introduce new aerial systems that occupy the operational space between satellites and conventional aircraft. Its presentation at DSEI 2025 underlines the growing demand for persistent, flexible, and cost-effective surveillance and communications solutions. The deployment of this technology points to the wider proliferation of stratospheric aircraft, a development that could reshape the balance between air and space platforms in defense and security.
