Solar Impulse 2 has broken the record for the longest non-stop solo flight without refueling.

The solar-powered plane spent 76 hours into the latest leg of its attempt to circumnavigate the globe.

Pilot Andre Borschberg is making steady progress as he attempts the first solar-powered crossing of the Pacific.

After leaving Nagoya, Japan, early on June 29, Andre Borschberg has now passed Midway Island and is heading towards his destination of Kalaeloa, Hawaii.

At 76 hours into the journey, Andre Borschberg broke the record for the longest ever non-stop solo flight without refueling.

The previous mark was set by the American Steve Fossett in 2006.

Steve Fossett’s jet-powered Virgin GlobalFlyer vehicle completed a full circumnavigation of the world in that time, travelling more than 41,000km.

In contrast, Andre Borschberg’s Solar Impulse plane, which carries no fuel at all, had gone “only” some 5,500km in its 76 hours of flight.

On July 1, the Swiss pilot fly a holding pattern to time his encounter with an upcoming cold front to the optimum.

This will occur on July 2, and Andre Borschberg needs good sun conditions to get his aircraft up and over the weather system so that he can navigate the final stretch into Kalaeloa on July 3.

Precisely when this historic landing will occur is somewhat uncertain.

Solar Impulse has some quite strict constraints to ensure the 72m-wingspan vehicle can put its wheels down safely.

These include a maximum cross wind of no more than four knots and a maximum overall wind speed of no more than 10 knots.

If it is too windy at ground level, Andre Borschberg will be instructed to circle overhead until the conditions calm down.

By then, Andre Borschberg will probably have spent more than 120 hours in the air.

So far, the pilot has coped remarkably well on very little sleep, and on July 1 even made time to joke around in his cockpit by donning a wig and fake beard.

When Andre Borschberg gets to Hawaii, he will be met by fellow adventurer and business partner, Bertrand Piccard.

Andre Borschberg and Bertrand Piccard have shared the flying duties in the single-seater plane’s round-the-world quest, which began in Abu Dhabi, UEA, back in March.

It is Bertrand Piccard – who famously made the first non-stop global circumnavigation in a balloon – who will fly the next leg from Kalaeloa to Phoenix, Arizona.

That is not quite as far as the current stint, but it still likely to take four days and nights.

From Phoenix, Solar Impulse 2 will head for New York and an Atlantic crossing that would eventually see the plane return to Abu Dhabi.

Andre Borschberg and Bertrand Piccard have used the various stopovers on their round-the-world journey to carry a campaigning message on the topic of clean technologies to local populations.

Their Solar Impulse plane is not intended as a demonstration of the future of aviation. Rather, it is to supposed to show off the capabilities of solar power in general.

Solar Impulse 2 is covered in 17,000 photovoltaic cells across its wings. These either power the vehicle’s electric motors directly, or charge its lithium-ion batteries, which sustain the plane during the night hours.