The Solar Impulse 2 set off to fly the entire globe, without burning any fuel, from Abu Dhabi on 3 March. It's the world's first plane capable of flying day and night without using any fuel or stopping, thanks to solar power.
The Solar Impulse 2 moves at the pace of a homing pigeon meaning this round the world attempt is going to take around five months of flying to cover the 32,000km trip.
Of course it will have to land to keep the flesh-bag human pilot alive. But it should stay up for five days straight when crossing the 8,500km Pacific stretch.
So how is this possible? 13 years of research, testing, and a whole lot of tech and innovation. Here's what you need to know.
Size is everything
The Solar Impulse 2, as the name suggests, is powered by the light of the sun. Since this doesn't offer huge amounts of power it has to be super lightweight. Hence being a carbon fibre single seater plane.
The wings of the Solar Impulse 2 span a hefty 72 metres. That's bigger than a 747 commercial airplane which is just over 68 metres. Despite its size the Solar Impulse 2 weighs in at just 2,300kg, which is about equivalent to a car. That's less than 1 per cent of the weight of an A380 commercial aircraft.
The reason the Impulse 2 needs to be so massive is mainly so that it can cram in as many solar panels as possible. But it's also so the wingspan can be wide enough to offer the most efficient gliding in-flight to keep it airborne without requiring much power.
How powerful is the Solar Impulse 2?
When it comes to power the priority is giving enough to stay in the air and keep moving forward without weighing the plane down.
The top of the Impulse 2 features 17,000 solar cells to help absorb the energy of the sun. This directly powers four 17.5 CV motors while at the same time filling 633kg of lithium batteries with power so that the plane can continue to fly at night.
The result is a completely renewable energy powered machine that moves along at between 50 and 100 kilometres per hour, which is about 30 to 62 miles per hour.
Andre Borschberg, a former Swiss air force pilot and the company's co-founder and chief executive says: "Solar Impulse 2 must accomplish what no other plane in the history of aviation has achieved - flying without fuel for five consecutive days and nights with only one pilot in the unpressurised cockpit." Here he is referring to the stretch across the Pacific ocean.
The Solar Impulse prototype has already flown across America and broken eight world records in the process.
The Solar Impulse 2 world trip will be piloted by chairman Bertran Piccard and co-founder André Borschberg alternating flights.
Anyone can follow the flights, including ground control video coverage at solarimpulse.com. This also shows the planned route for the journey.