The fully solar-powered airplane Solar Impulse 2 left Hawaii last week our time and safely landed at Moffett Airfield in California on Sunday, finally completing the crossing of the Pacific Ocean and bagging a few (pending) world records in the process.

It was in July last year that Solar Impulse 2 arrived in Hawaii after a historic flight that broke multiple records. That 7,212 km leg from Japan to Hawaii cost the aircraft dearly; with the plane’s lithium chemistry batteries damaged by overheating due to the use of too much insulation.

It wasn’t until early this year that new batteries were manufactured and installed.Pilot Bertrand Piccard touched down at Moffett Airfield after the 4,523 km trip; likely a tad tired after being cooped up in the cockpit for 62 hours, but certainly ecstatic.

Pilot Bertrand Piccard touched down at Moffett Airfield after the 4,523 km trip; likely a tad tired after being cooped up in the cockpit for 62 hours, but certainly ecstatic.

“Solar Impulse showcases that today exploration is no longer about conquering new territories, because even the moon has already been conquered, but about exploring new ways to have a better quality of life on earth,” said Mr. Piccard.

“It is more than an airplane: it is a concentration of clean technologies, a genuine flying laboratory, and illustrates that solutions exist today to meet the major challenges facing our society.”

Solar Impulse 2 has a wingspan of 71.9 m; just a little less than the world’s largest passenger airliner. While of rather gargantuan proportions, it’s a featherweight thanks to a carbon fibre body and tips the scales at just 2.3 tonnes.

17,248 ultra-thin monocrystalline silicon cells are mounted on the wings, fuselage and horizontal tailplane; collecting up to 340kWh of solar generated electricity per day.

The energy harvested by the solar cells is stored in lithium polymer batteries mounted in the four engine nacelles. The 633 kg of batteries (around a quarter of the plane’s weight) have an energy density of 260 Wh / kg.

Four brushless, sensorless motors, each generating 17.4 hp are mounted below the craft’s wings; propelling Solar Impulse at speeds of between 36 km/h (20 Kts) and 140 km/h (77 Kts). During the Hawaii to California leg, Solar Impulse averaged 65.9 km/h.

“Solar Impulse is a demonstration of energy efficiency and smart energy management, similar to a flying grid,” said André Borschberg, CEO and Co-founder of the Solar Impulse project.

“Just imagine your energy reserves increasing during flight and available day after day! This is what we may be doing in our communities, our cities and our countries.”

Solar Impulse will now continue its journey on to New York, then Europe or North Africa. Then it’s back to Abu Dhabi in the United Arab Emirates; completing the round-the-world mission.

One of the companies supporting the Solar Impulse team is ABB. The company is probably best known in Australia for its solar inverters; a popular choice in residential and commercial solar power systems.

“ABB’s alliance with Solar Impulse reflects our shared belief that with clean technologies, such as solar power, we can run the world without consuming the earth,” said ABB CEO Ulrich Spiesshofer.

Photo credit: Tobrouk