Jason LombergBack in April, we reported on the Impulse HB-SIA, a solar-powered aircraft piloted by balloonist Bertrand Piccard. Powered by 11,628 monocrystalline silicon cells, and with a wingspan equivalent to an Airbus A340 (63.4 m), the HB-SIA is an impressive piece of work. Yesterday, the craft achieved an important milestone: the first solar-powered night flight.

Piloted by Andre Borschberg, the HB-SIA took off on 7/7 from Payerne air base in Switzerland at 07:51 local time. The craft reached a maximum altitude of 8,564 m and stayed aloft for a total of 26 hours and 9 minutes. About two hours before sunset, the HB-SIA switched to battery power in preparation for night flight.

Solar Impulse HB-SIA

Borschberg, a former Swiss air force pilot, was ecstatic, to say the least. “It was unbelievable, success better than we expected. We almost thought to make it longer,” he said.

The HB-SIA weighs a mere 1,600 kg and achieves energy conversion efficiency of 22%. The four 10 HP motors (located beneath the wings) propel the craft to an average speed of 70 km/h (44 mph). During Wednesday’s historic flight, the HB-SIA hit a max speed of 68 knots (ground speed), or 78.25 mph.

What’s next for Captain Piccard? The next milestone will be crossing the Atlantic, followed by a round-the-globe flight by 2012. The ultimate goal is to achieve “impossible things” with renewable energies.

“We are on the verge of the perpetual flight,” said Piccard.