Flying high

Since its debut flight in 2009, the Solar Impulse HB-SIA aircraft has rung up an impressive series of accomplishments. In 2010, it set a record for the longest manned solar flight, staying in the air for 26 hours and becoming the first plane of its type to fly through the night. In 2012, it achieved the first intercontinental solar flight, setting off from Spain and landing in Morocco. And in July 2013, it added another breakthrough to the list, with the successful completion of the Across America project: a journey from one side of the USA to the other, starting on the west coast in San Francisco and finishing up in New York two months later.

The trip was done in five stages, with pilots Andre Borschberg and Bertrand Piccard taking turns at the controls. The first leg, which lasted 18 hours, took them as far as Phoenix, Arizona, while the second – from Phoenix to Dallas, Texas – earned the project yet another world record, for the longest distance covered in a single solar flight. After two further stopovers in Missouri and Washington D.C., the Solar Impulse touched down at New York’s JFK airport just after 11pm on Sunday 6 July, despite complications caused by a large tear in the left wing.

The Solar Impulse is able to fly such lengthy distances due to its ingenious design. Almost 12,000 photovoltaic cells cover the upper surface of its wings, maximising the amount of sunlight converted into electricity every second. During the day, these cells are also used to charge large lithium-ion batteries, which allow the plane to continue to fly even when the Sun has set. And despite its massive 63-metre wingspan, the aircraft weighs just 1600 kilograms, making it as wide as a commercial passenger jet but only a fraction of the weight. This enables it to reach top speeds of 70 kilometres per hour.

The Solar Impulse team hopes that, by demonstrating solar technology’s potential, their work will encourage governments around the world to invest in further research and development, leading to cleaner, more environmentally friendly energy sources. And their pioneering adventures have only just begun, with work already underway on the HB-SIA’s successor – a more advanced version of the aircraft that the team hopes to take on a round-the-world flight in 2015.