A Swiss pilot and his flying partner have set out to become the first people to circumnavigate the globe in a solar-powered plane.
According to the Guardian, Andre Borschberg and Bertrand Piccard took off from Abu Dhabi early Monday to embark on a five-month journey spanning 21,747 miles.
The trip will consist of 12 legs and carry them over the Atlantic and Pacific Oceans, both of which are expected to take five or six days to cross.
Their aircraft is called the Solar Impulse 2 and is powered by 17,000 solar panels.
Its wings are several meters wider than a Boeing 747's, but it weighs just 2.3 tons, or about as much as a standard-size sedan.
About a quarter of this weight is occupied by the lithium batteries that will power the Solar Impulse 2 at night.
The plane's top speed is 87 mph, but the men will be going about half that speed to conserve power.
A lack of sun, however, could potentially force the plane to stay grounded for weeks.
Perhaps the most grueling aspect of the trip will be staying healthy and alert inside a cockpit that is roughly the size of a driver's seat in a car.
In this seat, they'll eat, sleep, relieve themselves and spend a total of 250 hours each with no temperature control, even though it could reach below -40 degrees Fahrenheit outside.
Borschberg and Piccard will take turns flying and staying awake for several days at a time, only sleeping for quick, 20-minute naps.
The two say they will use yoga and self-hypnosis to remain focused.
Borschberg told the Guardian,
If you start thinking about how many hours left until you get to the destination you get crazy. So the only way is to be present... In some ways it's almost a spiritual experience that we are going through.
Borschberg is a former air force pilot and web entrepreneur, and his partner is a member of the team that became the first to circumnavigate the globe in a balloon in 1999.
The trip's utmost purpose is to display the capabilities of solar power, which is slated to become the world's primary source of electricity by 2050, according to the BBC.
Prices for solar panels are predicted to decrease by 50 percent within the next few years, when such technology finally becomes a serious competitor for gas in terms of cost-efficiency.
The first leg of the Solar Impulse 1 reached the Arab nation of Oman after about 12 hours in the air.