Solar Impulse: The world’s longest solo flight, fuel free

At the beginning of the week a plane took off to fly from Japan to Hawaii. That is not particularly unusual; scores do so each week. But this one had no passengers, no cargo and no fuel on board. Just one pilot, a few days of snacks and a ton of solar cells atop the wings. This morning, after roughly 5 full days in flight, Solar Impulse will touch down on the big island of Hawaii, having covered more than 5,000 miles in the air and consuming not a drop of JET-A.

The Solar Impulse mission is focused on sharing the message “The Future Is Clean” and countering climate change with new technologies which have resulted in this week’s record-setting adventure. It is now the longest solo flight in history and was performed in a “100% clean” manner. The project has brought about or leveraged advances in battery and solar power technologies, insulation, aerodynamics and communications systems.

And, thanks, to actually putting the technology into use, it serves as a great test bed to see how the new technologies work in the real world rather than in a lab. Learning how the batteries, specially optimized for this aircraft and its missions, have fared and seen internal temperature variation, for example, will help Solvay improve its designs for future generations of similar batteries which will ultimately find their way into consumer devices like cell phones or larger systems live electric autos.

Following along as Solar Impulse prepares to land in Oahu after five days in flight.
Following along as Solar Impulse prepares to land in Oahu after five days in flight.

The entire flight has been live-streamed, including on-board telemetry, audio and video. Much easier to do when you only have one person on board, of course, but still an impressive display of satellite communications and what is possible with today’s technology. And, like the batteries, we can very readily see where the connectivity improvements will come from given the growth of capacity, reduction of component size and increases in system efficiency which are all happening so rapidly in the industry today.


One of the incredible bits about the trip is that they aren’t just flying as fast as possible to complete the segment. Due to weather and things like needing to have daylight for the landing the trip has actually been even longer than absolutely necessary, including some holding patterns at various points along the way. It makes sense but still hard to believe that after flying so long they need to slow down the progress.

And, seriously, a five day flight without fuel is simply incredible. I’m in awe.

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Seth Miller

I'm Seth, also known as the Wandering Aramean. I was bit by the travel bug 30 years ago and there's no sign of a cure. I fly ~200,000 miles annually; these are my stories. You can connect with me on Twitter, Facebook, and LinkedIn.