After spending the summer on the finishing and fine-tuning of their airplane, Bertrand Piccard, André Borschberg and their team will be rolling out the prototype Solar Impulse HB-SIA from its construction hall for the first time and beginning ground testing, followed by the first controllability tests a few metres above the runway at Dübendorf airfield (ZH).

On Monday October 19, the engineering team officially handed over the solar aircraft to the test team, headed by Swiss astronaut Claude Nicollier. Professional test pilot and aerodynamics engineer Markus Scherdel will be at the controls of the prototype for these first tests. This is a crucial step in the project, as it is vital to check, before starting flight missions, that the aircraft's behavior and controllability match the calculations and simulations undertaken over these last 6 years. Testing is scheduled to take place between November 2 and December 20, 2009. The exact dates and times will depend on weather conditions – an absence of wind, rain or fog – and the decision to test will be taken in each case in the preceding 24 hours.

With all these technical and weather constraints, it is difficult to give a precise timetable. Testing will take place in several steps:

1st exit from the hangar - On-ground testing of the four motors and checking that all systems function correctly

Test runs down the runway - Testing the aircraft's controllability in acceleration and deceleration phases

Flight tests on the runway (first take-offs) - The aircraft will take off just a few metres above the runway, with initial 'flea-hops', just like the Wright brothers in 1903! The aim is to test the controllability of this immense wing, but without yet connecting the solar generator

Following these tests, the aircraft will be transported to Payerne airfield (VD), where successive solar test flights will take place at a higher altitude and over ever longer distances. The aim is to be ready, by spring 2010, for a complete day-night-day cycle, a vital stage in approaching the concept of perpetual flight.

Solar Impulse HB-SIA, the first aircraft designed to fly day and night without fuel or pollution

Six years of intense hard work, calculations, simulations and tests by a 70-persons team have gone into completing this totally new carbon fibre aircraft, with the wingspan of an Airbus A340 (63.4 m) and the weight of an average family car (1600 kg). Never before has such a large and lightweight aircraft been seen. Almost 12,000 solar cells, integrated into the wing, feed renewable energy to the four electric motors with a maximum power of 10 HP each, and by day also charge the lithium-polymer batteries (400 kg) which will enable the aircraft to fly at night.