Solar-Powered Flight:

Across the U.S. and Beyond

By Alex Starace

crossing_america_test-flightAdventurer Bertrand Piccard has a life straight out of a Jules Verne novel. In 1999, he and Brian Jones were the first to complete a non-stop circumnavigation of the world in a hot air balloon. The trip, which took nearly 20 days, used 8,200 pounds of propane. Piccard, motivated by such an incredible waste of resources, decided to better the endeavor: 
develop a flying machine that’s powered entirely without fossil fuel.



The Solar Impulse Project

Piccard teamed up with the engineer and former Swiss Air Force pilot André Borschberg to launch the Solar Impulse project in 2003. The duo’s goal: fly around the world fossil-fuel-free in 2015.

So far, they’re on pace. In 2010, their first plane, the HB-SIA, flew for 26 consecutive hours (including through the night) using only solar power – and it had four hours of banked energy when it landed. In 2013, the Solar Impulse team flew across the United States, from San Francisco to New York, in a five-leg journey. According to Piccard, their plane can fly forever – the only limitation is the pilot’s stamina.

san-francisco-bayThe Secret to Solar Flight

The HB-SIA minimizes the energy needed to keep it aloft by being incredibly light – its wingspan of 208 feet matches that of 
a jumbo jet, while its weight of 3,527 pounds is only that of an average car. And its cabin is miniscule – it has room for one pilot and no passengers. For the planned 2015 flight around the world, which will likely last over a week, Piccard and Borschberg are developing the HB-SIB, a model that has a cabin accommodating two pilots, allowing them to take turns.

Despite this immense progress, solar flight is currently far from commercial viability. Aside from having only one passenger, the HB-SIA flies at a pokey 45 miles per hour, has no cabin pressure (meaning the pilot is subject to extreme temperatures and must breathe using imported oxygen), and cannot take off or land if ground winds exceed 11.5 miles per hour.

However, immediate commercial flight is not the goal, according to Piccard. Instead, he wants to inspire others to implement 
solar energy in ground-based activities; and to show that the seemingly impossible – flying using only the power of the sun – can 
be done.

Solar-Powered Flight: