SolarsStratos
A new aviation milestone has been reached as a solar-electric, propeller-driven plane climbed higher than any of its kind before—though the feat still awaits official recognition. On August 12, 2025, a customized Elektra One soared to 31,237 feet (9,521 m) above Switzerland.
The Record-Breaking Mission
The aircraft, registered as HB-SXA, took off from Sion Airport with SolarStratos founder Raphaël Domjan at the controls. The mission lasted five hours and nine minutes, powered solely by solar energy, including a two-hour ascent and a three-hour descent across the Valais Alps.
Engineering and Design Features
Weighing only 992 lb (450 kg), the HB-SXA features an 81.4 ft (24.8 m) wingspan lined with solar cells, which supply a 43-bhp electric motor said to run at 90% efficiency. A 20-kWh lithium-ion battery serves as backup, enabling up to 24 hours of flight.
SolarsStratos
Although modest in power, the aircraft is essentially a motorized glider optimized to ride thermals and updrafts to maintain altitude. It forms part of the SolarStratos initiative, a Swiss program showcasing the potential of solar and electric propulsion for long-duration, high-altitude missions, with the ultimate goal of reaching the stratosphere at 82,000 ft (25,000 m).
Challenges of High-Altitude Flight
To achieve this, engineers designed the plane to be extremely lightweight, leaving the cockpit unpressurized. Domjan therefore flew in a custom pressure suit to withstand both the thin atmosphere and frigid conditions.
While SolarStratos reports surpassing the previous record of 30,298 ft (9,235 m) set by Solar Impulse 3 in July 2010, the achievement remains unofficial until validated by the Fédération Aéronautique Internationale (FAI).
Read the original articel on: New Atlas
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