Pilots Bertrand Piccard and Andre Borschberg will split duties of flying the Solar Impulse 2: a plane that's wider than Boeing 747, but weights only 2.3 tonnes: naturally, weight's important when you're being powered by solar. Across the wingspan, the team has installed 17,000 solar cells, while high-capacity lithium batteries on board will power the flight in the night-time. (Each leg will take several days and nights to complete.)

Update: Takeoff's been delayed as the team runs through some last-minute technical checks. It looks brutally early in Abu Dhabi: presumably the team needs to maximize the sunlight that the plane can pick up.