Today – up to about 19:30 – the prototype will slowly ascend to an altitude of 8,500 meters, while at the same time charging its batteries in preparation for the night flight. When the suns rays stop being strong enough to supply the solar cells (about two hours before sunset) with energy, says the company, the HB-SIA will start a slow descent, reaching an altitude of around 1,500 meters by 23:00.
It should then carry on flying, using the energy stored in its batteries, until the next sunrise. The big question, it continues, is whether the pilot can make efficient use of the battery energy to fly throughout the night. If this mission is successful, it will be the longest and highest flight ever made by a solar plane.
For seven years now, the whole team has been passionately working to achieve this first decisive step of the project, said André Borschberg CEO and co-founder of the project a few minutes before easing himself into the cockpit.
The intention of this mission is to demonstrate the potential of renewable energy and clean technologies and to promote them amongst the public, added Bertrand Piccard, initiator and president of Solar Impulse.