Swiss Solar-Powered Electric Aircraft Soars to Unofficial Altitude Record of 9,521 Meters

On August 31, it was revealed that a propeller-driven solar-electric aircraft has reached a new, unofficial altitude milestone for its class. On August 12, a modified Elektra One soared above Switzerland, climbing to an impressive 31,237 feet (approximately 9,521 meters).

The record-setting flight was piloted by Raphaël Domjan, founder of the pioneering SolarStratos project. Registered as HB-SXA, the aircraft took off from Sion Airport and completed a 5-hour and 9-minute journey powered entirely by solar energy. The climb over the Valais Alps took two hours, while the descent lasted three.

Weighing just 992 pounds (around 450 kilograms) and boasting an 81.4-foot (24.8-meter) wingspan, the HB-SXA is equipped with solar panels across its wings, feeding a 43-horsepower electric motor with an impressive 90% efficiency rating. A 20 kWh lithium-ion battery serves as a backup power source, theoretically enabling up to 24 hours of continuous flight.

While its power specifications may seem modest, HB-SXA is fundamentally a motor glider, designed to harness thermal and other rising air currents for altitude gain and sustained flight. As part of the SolarStratos initiative, the aircraft serves as a testbed for demonstrating the viability of solar and electric propulsion in high-altitude, long-endurance missions. The project’s ultimate ambition: to ascend to the stratosphere, reaching 82,000 feet (around 25,000 meters).

To achieve this, the aircraft has been extensively lightened — including the absence of a pressurized cockpit. During this record attempt, Domjan wore a specialized pressurized suit to withstand the low pressure and extreme cold encountered at high altitude.

According to the SolarStratos team, this flight surpasses the previous record of 30,298 feet (about 9,235 meters) set on July 9, 2010, by the Solar Impulse 3. However, this new achievement awaits official certification from the Fédération Aéronautique Internationale (FAI).