Solar Impulse 2, a solar-powered airplane built to fly around the world next year, took its first test flight yesterday morning. Test pilot Markus Scherdel took off in the plane at 5:38 Central European Time from Payerne airport, Switzerland, and landed at 7:52, according to the Solar Impulse website. Scherdel reported some unintended vibration but the team attributes it to the landing gear.
Solar Impulse is a project spearheaded by Bertrand Piccard, an adventurer who circumnavigated the Earth in a hot air balloon in 1999, and is funded by a large private consortium. The consortium built a prototype, dubbed Solar Impulse 1, in 2009. That plane achieved solar-powered flights across the Mediterranean and across the United States with four stops. It also flew for an entire night, using energy it had captured during the previous day's flight (see also IEEE Spectrum's Q&A with a Solar Impulse rep during the first 24-hour solar-powered flight).
Solar Impulse 1's bigger, more advanced sibling weighs 2300 kg, of which 633 kg are lithium batteries for storing the energy generated by the plane's 17 000 solar cells. The batteries have new electrolytes intended to achieve an energy density of 260 watt-hours per kilogram, and the plane uses a new kind of carbon fiber that keeps its weight down. The plane takes off at bicycle speeds, which is handy since its wings, which span 72 meters, need spotters on bicycles to ensure that they do not strike the runway.
The team will spend this summer testing and certifying the new model ahead of next year's attempt.