The Solar Impulse 2 was on Monday approaching the end of its epic bid to become the first sun-powered airplane to circle the globe without a drop of fuel to promote renewable energy.
When the experimental aircraft touches down in Abu Dhabi in the early hours of Tuesday it will cap a remarkable 42,000-km journey across four continents, two oceans and three seas.
With Swiss explorer and project director Bertrand Piccard in the cockpit, the plane is due to land at Al-Bateen Executive Airport in the UAE capital where it launched its tour on March 9, 2015.
By 1300 GMT on Monday, Solar Impulse 2 had travelled more than 2,200 km in nearly 38 hours on its final leg, flying over Qatar’s northern tip after crossing the vast Saudi desert.
“Thanks to our lovely #sun, #Si2’s batteries are fully charged,” the Solar Impulse team said on Twitter.
“After a turbulent night from extreme high temperatures, the sun rose above a desert of sand dunes above #SaudiArabia,” Mr. Piccard tweeted earlier.
Dubbed the “paper plane,” the Solar Impulse 2 is circumnavigating the globe in stages, with 58-year-old Piccard and his compatriot Andre Borschberg taking turns at the controls of the single-seat aircraft.
It took off from Cairo on its final leg early on Sunday, having previously crossed Asia, North America, Europe and North Africa.
Mr. Borschberg, 63, smashed the record for the longest uninterrupted journey in aviation history with the 8,924-km flight between Nagoya, Japan and Hawaii that lasted nearly 118 hours.
“#Si2 is both the 1st airplane of unlimited endurance & the only experimental aircraft allowed to fly over cities!” he tweeted on Monday.
No heavier than a car but with the wingspan of a Boeing 747, the four-engine battery-powered aircraft relies on around 17,000 solar cells embedded in its wings.
Its broad wings and light weight make it particularly sensitive to turbulence.
The plane has clocked an average speed of 80 km per hour.