Theoretically, at least.

We’ve written before about the Solar Impulse, a carbon-fibre monoplane powered entirely by the sun. Back in 2010, this lightweight aircraft became the first solar-powered plane to fly overnight for 24+ hours, and aviation pioneers Bertrand Piccard and Andre Borschberg — who previously had circumnavigated the globe in a balloon — plan to make history again with the Solar Impulse 2, which will undertake the first solar-powered flight around the world.

Read: Making aviation history: A solar-powered plane

The Solar Impulse 2 will fly non-stop for 120 straight hours without stopping for food, fuel, or supplies (or bathroom breaks). In fact, the only thing stopping the aircraft from flying indefinitely is the biological requirements of the pilot.

See: Photos of the Day: Solar-powered plane to circle the globe

"It can fly a day and a night, it can fly a week, it can fly a month — theoretically it can fly a year," said Andre Borschberg. "It's the most energy efficient airplane ever built," he added.

And while the tiny cockpit — about 1 ½ times the volume of a Mini Cooper — will use a high-density foam to protect the pilot from the elements, which span -40°C +40°C, the trip will be cramped, boring, and sap the onboard supplies, so the intrepid pioneers will switch off at each continent.

Still, each leg of the trip will last five successive days and nights, which will present numerous technological and psychological problems.

Despite a wingspan wider than a Boeing 747, the Solar Impulse 2 weighs a mere 2,300 kilos, about the same as a family car. Every inch of real estate is dedicated to energy efficiency, and its gargantuan wings are covered by 17,000 solar cells which power the four onboard electric motors and keep the aircraft aloft, albeit chugging along at a plodding 88 mph.

But the Solar Impulse 2’s historic flight will be just as much a human feat as a technical achievement. The pilots must condition their minds to deal with the solitude of a five-day flight alone in a cramped cabin, and similar to astronauts, Piccard and Borschberg will need to perform physical exercises to keep the circulation flowing.

Even sleep will be a challenge. The duo will need to practice something called “polyphasic sleep”, or sleeping multiple times throughout the day. Actually, they’ll be essentially taking numerous catnaps, lasting up to 20 minutes each. (If you were the sole pilot in a transatlantic voyage, would you feel comfortable sleeping longer than that?)

"You need to know how to rest, how to eat, when to go to the toilet and how to keep the body functioning,” said Borschberg. “Of course, we've also prepared for the worst — how to jump out if it's necessary, how to survive in the ocean with a small life raft and how to get rescued," he said.

And going to the bathroom? A multipurpose seat will function as a toilet. Yeah ... gross ...

The Swiss duo is attempting to promote a more sustainable way of life — even if the Solar Impulse 2’s ordeal is beyond the physical and psychological capabilities of most people on the planet — but I‘m excited to bear witness to such an astounding triumph in aviation and human achievement.

Piccard and Borschberg will begin their 35,000-kilometer flight in March 2015.