The Solar Impulse 2, which completed the world’s first flight around the globe powered only by solar energy in 2016, has crashed into the ocean following an 8-day autonomous maritime patrol flight.
Solar Impulse 2 boasted a nearly-71-metre wingspan and was powered by 17,248 solar cells and 4 lithium-ion batteries connected to the electric motors, and completed its circumnavigation of the globe in 2016 after a much-interrrupted flight spread over 16 months.
Pilots Bertrand Piccard, who conceived of the Solar Impulse idea, and Swiss pilot André Borschberg, made 17 stops along the route and racked up a total of 21 days of flight.
The Solar Impulse Foundation, which was founded by Piccard and Borschberg in 2004 to advocate for clean energy technologies, sold the Solar Impulse 2 in 2019 to Skydweller Aero, an American-Spanish aerospace company pioneering unmanned solar-powered aircraft.
Unlike its originally intended purpose of advocating for solar power, Skydweller Aero is focused on the military and law enforcement capabilities of uninterrupted flight and the revamped Solar Impulse 2 completed its first autonomous flight in 2023.
Reports emerged early last week that Solar Impulse 2 had crashed into the Gulf of Mexico during an autonomous test flight a week prior. A notification from the US National Transport Safety Board (NTSB) reported that the plane had been destroyed with no injuries.
Skydweller Aero insisted that the Solar Impulse 2 had not crashed but had rather executed “a controlled water ditching” following its participation in a US Navy exercise in which it completed an 8-day (192-hour) and 14-minute autonomous and uninterrupted maritime patrol flight.
It said once it had completed the patrol flight, Solar Impulse 2 “remained airborne to wait out a large cold front covering the Gulf”, leading to one and a half days of “weather-constrained loitering” before a window opened for it to return to base.
However, during the plane’s return transit, “the aircraft encountered more severe weather than forecast, including heavy turbulence and vertical drafts, causing climb and descent rates in excess of ten times typical rates.
“While the airframe and autonomy systems performed as designed, these conditions required more power than expected to maintain altitude, leading to a controlled ditch on the morning of May 4.”
It said the controlled ditching was executed only after the plane’s energy reserves were depleted by sustained and extreme weather conditions.
The Solar Impulse Foundation announced a few days later that it had “learned through social media about the crash” and were awaiting further information. This was followed up several days later with a subsequent announcement in which the Foundation repeated Skydweller Aero’s findings.
“Despite the loss of the aircraft, Skydweller exceeded its initial target of seven days’ endurance, and all systems, including the flight controls, performed as expected,” Piccard and Borschberg said in a statement.
“This confirms that the incident was due to extreme weather conditions and not a technical failure. This is reassuring news for the team of engineers who designed and built this technological marvel, which has flown successfully for 12 years, first around the world as Solar Impulse 2, and then autonomously as Skydweller.
“Although saddened by the loss of our ‘beautiful bird’, we are reassured that the aircraft has in fact completed its entire operational life cycle and has, once again, successfully demonstrated the ability to carry out autonomous operations lasting several days powered by solar energy.”
