The flight took place in the team's home country of Switzerland, at the Payerne airport. Flown by test pilot Damian Hischier, the aircraft took off at 8am and proceeded to fly for seven minutes at an altitude of 300 metres (984 ft) before landing and returning to its hangar. Raphael Domjan, who will pilot the plane on its stratospheric mission, looked on from the runway throughout.
"The plane is very nice to fly," Hischier said afterwards. "It is responsive and it is obvious that it has been very well designed and built."
SolarStratos is equipped with 22 sq m (237 sq ft) of solar panels. These charge a 20 kWh lithium-ion battery pack, which powers a 32-kW electric motor that in turn drives a 2.2-m (7.2-ft) propeller. It measures 8.5 m (27.9 ft) long, has a wingspan of 24.9 m (81.7 ft) and weighs in at just 450 kg (992 lb).
Designed by Calin Gologan, it is reportedly able to fly continuously for over 24 hours, which is more than enough to cover the expected two-and-a-half hours it will take to reach the stratosphere, 15 minutes cruising at peak altitude and three hours to return to the Earth.
Other test flights at higher altitudes are now in the works, with the final mission scheduled to take place next year.
"Our plane, which can fly at 25,000 metres, opens a window to electric and solar-powered high-altitude aviation – something that has never before been attempted," said Domjan. "Only by flying can we work out the plane's limits and today's short flight was an important first step on this pathway."