A Swiss pilot claims to have broken the more than 15-year-old altitude record for electric, solar-powered aircraft.
Raphaël Domjan on Tuesday flew an electric plane propelled by solar cells, registered HB-SXA, to an altitude of 9,521 meters, or over 31,200 feet, according to his SolarStratos project. At that altitude, SolarStratos said, Domjan soared over the Swiss Alps and even crossed paths with a commercial airliner.
“Up there, facing the sun that powers our wings, flying without burning a single drop of fuel is an indescribable feeling…a moment out of time,” Domjan said in a post on LinkedIn.
Despite falling just short of its 10,000-meter target, the flight surpassed the 9,232-meter altitude achieved by André Borschberg in 2010 with Solar Impulse—another Swiss experimental aircraft project.
The World Air Sports Federation is reviewing Domjan’s flight to determine whether it qualifies for the record.
“The mythical 10,000-meter mark is within reach,” he said. “Next goal: touch the stars with nothing but the power of the sun.”
Stratospheric Odyssey
Domjan is on a mission to prove that sustainable aircraft can equal or even surpass the capabilities of traditional technology. SolarStratos describes the 42-year-old plane, helicopter, and glider pilot as an “eco-adventurer.” Domjan previously led the PlanetSolar project, during which he captained the first trip around the globe by a solar-powered electric boat.
After hitting 10,000 meters, the Swiss pilot will embark on what SolarStratos calls a “stratospheric odyssey.” The mission is expected to last just over six hours, with about 15 minutes spent at stratospheric altitude. There, Domjan will take “unprecedented measurements” of the atmosphere, which will be shared for scientific research and the development of future sustainable but high-performance aircraft.
The SolarStratos aircraft was built by Germany’s Elektra Solar with thermal management systems designed to handle this extreme environment, where temperatures can approach minus-70 degrees Celsius. Its canopy is designed to protect Domjan—whose pressurized suit pumps in oxygen to aid breathing—from high-altitude conditions.
HB-SXA’s solar cells cover an area of more than 230 square feet on the wing, powering lithium-ion batteries, a double electric motor, and a front-mounted, three-bladed propeller. The propulsion system generates about 50 kilowatts of continuous power and zero pollution, per SolarStratos.
The aircraft’s long, slender wing—spanning about 81 feet—creates a high lift-to-drag ratio that is ideal for fast climbs and low-speed flight. The wing and fuselage are made entirely of carbon fiber. Its cockpit contains “usual aeronautic equipment as well as specific equipment for solar and electric flight,” with a pair of tandem seats.
Altitude Ambitions
HB-SXA surpassed 100 flight hours on July 31—the same day that a preparatory flight reached 6,589 meters. Despite limited time in the sky, the design is already reaching new heights for electric and solar-powered aviation.
The potential record-setting flight took off on Tuesday from Switzerland’s Sion Airport (LSGS), lasting 5 hours and 9 minutes. According to SolarStratos, it was powered entirely by solar energy, with some help from thermal updrafts. Per CBS News, the aircraft must recharge its batteries at an altitude of 4,000 to 5,000 meters before continuing its climb.
“A moment of great pride and emotion for the entire SolarStratos team—fittingly celebrated with a well-deserved raclette!” SolarStratos said in an announcement exalting the milestone.
SolarStratos and others pushing the boundaries of flight have plenty of reasons to celebrate as aviation regulators warm up to new technologies.
The final Modernization of Special Airworthiness Certification (MOSAIC) rule, for example, removes powerplant limitations for light sport aircraft, permitting the use of electric, hydrogen, and other nontraditional power sources. The FAA in July also published certification guidance for powered-lift aircraft—those capable of vertical takeoff and landing (VTOL) and wingborne forward flight, often using electric or hybrid-electric power.
Recent White House directives, meanwhile, promote the production of drones, electric aircraft, and spacecraft and order an end to the ban on supersonic flights over land.
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