The BAE Systems Persistent High Altitude Solar Aircraft (PHASA-35) is a

High-Altitude Long Endurance A high-altitude platform station (HAPS, which can also mean high-altitude pseudo-satellite or high-altitude platform systems), also known as atmospheric satellite, is a long endurance, high altitude aircraft able to offer observation or communi ...

(HALE)

unmanned aerial vehicle An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...

(UAV) developed by

BAE Systems BAE Systems plc is a British Multinational corporation, multinational Aerospace industry, aerospace, military technology, military and information security company, based in London. It is the largest manufacturer in Britain as of 2017. It is ...

in collaboration with Prismatic. Designed as a cheaper alternative to satellites, the aircraft can be used for

surveillance Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing, or directing. This can include observation from a distance by means of electronic equipment, such as ...

border control Border control comprises measures taken by governments to monitor and regulate the movement of people, animals, and goods across land, air, and maritime borders. While border control is typically associated with international borders, it als ...

communications Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...

and

disaster relief Emergency management (also Disaster management) is a science and a system charged with creating the framework within which communities reduce vulnerability to hazards and cope with disasters. Emergency management, despite its name, does not actu ...

with a potential ability to stay airborne for up to 12 months. Developed in less than two years, the aircraft carried out its first flight in February 2020 and further trials are currently ongoing.

Development

PHASA-35 was originally designed and developed by engineers who had previously worked on the

Zephyr In European tradition, a zephyr is a light wind or a west wind, named after Zephyrus, the Greek god or personification of the west wind. Zephyr may also refer to: Arts and media Fictional characters * Zephyr (comics), in the Marvel Comics univers ...

HAPS drone for

Qinetiq QinetiQ ( as in '' kinetic'') is a British defence technology company headquartered in Farnborough, Hampshire. It operates primarily in the defence, security and critical national infrastructure markets and run testing and evaluation capabili ...

. When Qinetiq sold Zephyr to

Airbus Defence and Space Airbus Defence and Space is a division of Airbus SE. Formed in 2014 in the restructuring of European Aeronautic Defence and Space (EADS), Airbus SE comprises the former Airbus Military, Astrium, and divisions. Contributing 21% of Airbus reven ...

in 2013, these engineers left and formed their own company, named Prismatic, to develop a rival aircraft. Development of PHASA-35 consequently began in 2018, in collaboration with BAE Systems, and a first flight was scheduled for 2019. Prior to this, a quarter-scale model, named the PHASE-8, completed a successful first flight in 2017. In September 2019, BAE Systems acquired Prismatic as a subsidiary. After less than two years in development, the PHASA-35 made its maiden flight on 17 February 2020 at the

Woomera Test Range The RAAF Woomera Range Complex (WRC) is a major Australian military and civil aerospace facility and operation located in South Australia, approximately north-west of Adelaide. The WRC is operated by the Royal Australian Air Force (RAAF), a S ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

with support from the UK's

Defence Science and Technology Laboratory The Defence Science and Technology Laboratory (Dstl) is an executive agency of the Ministry of Defence of the United Kingdom. Its stated purpose is "to maximise the impact of science and technology for the defence and security of the UK". The a ...

and Australian

Defence Science and Technology Group The Defence Science and Technology Group (DSTG) is a part of the Australian Department of Defence, which provides science and technology support to Defence and defence industry. The agency's name was changed from Defence Science and Technolog ...

. Further trials commenced and, in October 2020, the aircraft carried out an endurance trial whilst carrying a sensor payload. The trials saw the aircraft operating 72 hours whilst in a simulated environment of harsh stratospheric conditions. In January 2021, BAE Systems announced plans to carry out a flight demonstration in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

after acknowledging “strong growing interest” in the aircraft from across the

U.S. Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an executive department of the U.S. federal government charged with coordinating and supervising the six U.S. armed services: the Army, Navy, Marines, Air Force, Space Force, t ...

and federal agency customer base. By December 2024, it had flown for 24h and reached more than from

Spaceport America Spaceport America, formerly the Southwest Regional Spaceport, is an FAA-licensed spaceport located on of State Trust Land in the Jornada del Muerto desert basin north of Las Cruces, New Mexico, and southeast of Truth or Consequences. Wit ...

in New Mexico, targeting operational activity by 2026.

Design

The aircraft is a solar-electric HALE UAV designed as a cheaper alternative to

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

s and is able to carry out a range of tasks, including border protection, maritime and military surveillance, disaster relief and communications. It is powered by the sun during the day, before switching to battery power during the night and can potentially stay airborne for 12 months. Featuring long-life battery technology, ultra-lightweight solar cells, a wingspan and a weight of , the aircraft is designed to operate in the

stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...

. It has a payload capacity of 15kg.

References

{{reflist Solar-powered aircraft Unmanned military aircraft of the United Kingdom High-altitude platform stations BAE Systems research and development High-wing aircraft Twin-engined tractor aircraft PHASA-35 Aircraft with conventional landing gear Aircraft first flown in 2020 Aircraft with jettisonable landing gear

Development

Design

See also

References