The Zephyr operates on solar power, above the weather and conventional air traffic as a high-altitude pseudo-satellite. (Image source: Airbus)

Airbus Zephyr S breaks world flight endurance record during maiden flight

The Zephyr S flew for 25 days without refueling.
After taking off on July 11 in Arizona, the Zephyr S unmanned aircraft from Airbus Defence and Space in Ottobrunn, Germany logged a maiden flight of over 25 days – the longest-duration flight ever made without refueling. This first flight of the solar-powered Zephyr S operational concept demonstrator (OCD) aircraft ended August 6, proved system capabilities, and achieved engineering objectives.

The Zephyr S is a solar-electric, stratospheric unmanned aerial vehicle (UAV), often referred to as a “drone;” however, Airbus goes one step further and designates it as a “high-altitude pseudo-satellite” (HAPS). It harnesses the sun’s rays, running exclusively on solar power above the weather and conventional air traffic. It also fills a capability gap complementary to satellites, UAVs, and manned aircraft to provide persistent, local, satellite-like services, such as communication relay and persistent surveillance.

An application has been made to establish this event as a new world record. The flight was supported by the United Kingdom (UK) government and reflects the UK Ministry of Defence’s position as the first customer for this innovative and potentially game-changing capability. The UK MoD’s Operational Concept Demonstrator (OCD) contract with Airbus was signed in 2016 and includes the purchase of three Zephyr S platforms, with further flight trials planned for the coming months.

“This very successful maiden flight represents a new significant milestone in the Zephyr program, adding a new stratospheric flight endurance record which we hope will be formalized very shortly. We will in the coming days check all engineering data and outputs and start the preparation of additional flights planned for the second half of this year from our new operating site at the Wyndham airfield in Western Australia,” says Jana Rosenmann, head of Unmanned Aircraft Systems (UAS) at Airbus.

The Zephyr S on its maiden flight (Image source: Airbus)

The previous longest flight duration record was also logged by a Zephyr prototype aircraft – the Zephyr 7 – in July 2010, achieving then more than 14 days of continuous flight. At the time of the Zephyr 7 flight, the previous record was nearly 30.5 hours held by the Northrop Grumman RQ-4A Global Hawk unmanned surveillance aircraft – less than one tenth of the Zephyr 7 record.

(The longest refueled flight took place over 50 years ago from December 4, 1958 to February 7, 1965 and lasted nearly 65 days. Robert Timm and John Cook made the flight in a modified Cessna 172, periodically flying “low and slow” and refueling from a moving truck.)

The ultra-lightweight Zephyr weighs 75 kilograms (165 pounds), has a wingspan of 25 meters, and operates at an average altitude of 70,000 feet, flying above weather (clouds, jet streams) and regular air traffic. The only aircraft that regularly flew at this altitude was the Aérospatiale/BAC Concorde supersonic commercial airliner (retired) and the Lockheed SR-71 Blackbird (retired) and Lockheed U-2 (in service) strategic reconnaissance aircraft.

The original target mission of the Zephyr is to provide local persistence at an affordable price with a re-usable solar-powered aircraft, providing a wide scope of applications, ranging for example from maritime surveillance and services, border patrol missions, communications, forest fire detection and monitoring, or navigation.

(Image source: Airbus)

According to Airbus, the Zephyr will bring new capabilities to both commercial and military customers, providing the potential to revolutionize disaster management, including monitoring the spread of wildfires or oil spills. It provides persistent surveillance, tracing the world’s changing environmental landscape, and will be able to enable communications in the world’s most remote regions.

It can stay focused on a specific area of interest – up to hundreds of miles wide – while providing satellite-like communications and Earth observation services with greater image granularity or detail over long periods of time without interruption with – what Airbus refers to as – “see, sense, and connect” sensor payloads.

The Zephyr can be controlled from ground stations anywhere in the world using beyond-line-of-sight (BLOS) capabilities and has civil and military approval from countries across four continents, including Europe and Australia.

The larger Zephyr T is currently in development. It weighs 140 kilograms (308 pound), has a wingspan of 33 meters, and will be able to carry communication and sensor payloads with larger masses.


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William Kucinski is content editor at SAE International, Aerospace Products Group in Warrendale, Pa. Previously, he worked as a writer at the NASA Safety Center in Cleveland, Ohio and was responsible for writing the agency’s System Failure Case Studies. His interests include 'literally anything that has to do with space,' past and present military aircraft, and propulsion technology. And also sportscars.
Contact him regarding any article or collaboration ideas by e-mail at
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