Powered by over 17,000 solar cells, Solar Impulse 2 is attempting an arround the world flight depending only on solar energy and without a drop of fuel. Solar Impulse is the first airplane of perpetual endurance able to fly day and night.
The project founders are the Swiss pilots Bertrand Piccard, Initiator and Chairman along with André Borschberg CEO.
The project started 2003 with the aim of demonstrating clean technologies potential towards supporting a green world.
The Round The World (RTW) flight is the projetcs' high point evidencing clean energy capabilities, with a non-stop flight day and night without a drop of fuel.
The project started in November 2003, the major milestones since its inception are the following:
2006–09, first prototype construction carrying the Swiss registration HB-SIA or Solar Impulse 1.
26 June 2009, Solar Impulse 1 presented to the public at the Dübendorf Air Base, Switzerland
7 April 2010, 87-minute test flight reaching an altitude of 1,200 m (3,937 ft).
28 May 2010, the aircraft made its first flight powered entirely by solar energy, charging its batteries in flight.
8 July 2010, Solar Impulse 1 achieved the world's first manned 26-hour solar-powered flight, reaching a maximum altitude of 8,700 m (28,500 ft).The longest and highest ever flown by a manned solar-powered aircraft at the time.
3 May 2011, first international flight from home base in Switzerland landing at Brussels Airport, after completing a 13-hour flight, reaching an average altitude of 6,000 ft (1,800 m) for a distance of 630 km (391 mi), with an average speed of 50 km/h (31 mph).
5 June 2012, Solar Impulse 1 successfully completed its first intercontinental flight, a 19-hour trip from Madrid, Spain, to Rabat, Morocco. the flight included setting several further records for solar flight, including the longest solar-powered flight between pre-declared waypoints (1,099.3 km (683 mi) and along a course (1,116 km (693 mi).
3 May 2013, the plane began its cross-US flight with a journey from Moffett Field in Mountain View, California, to New York's John F. Kennedy International Airport on 6 July. The flight was completed on six flight legs, each flight leg took between 19 and 25 hours covering a total distance of 5,650 km (3,511 mi) and 105h 41min of flight time and setting a new world distance record of its category of 1,506 km (936 mi) in the second flight leg from Phoenix to Dallas.
2011, construction of the second aircraft carrying the Swiss registration HB-SIB or Solar Impulse 2.
9 April 2014, Solar Impulse 2 first public display. Its inaugural flight took place on 2 June 2014 at Payerne air base. The aircraft averaged a ground speed of 30 knots, and reached an altitude of 5,500 feet. The first night flight was completed on 26 October 2014, and the aircraft reached its maximum altitude during a flight on 28 October 2014.
January 2015, the aircraft delivered to Masdar in Abu Dhabi for the World Future Energy Summit
March 9 2015, take off for the Round The World (#RTW) flight.
The journey from Abu Dhabi to Honolulu was made over 8 flight legs with stops in Muscat in Oman, Ahmed Abad and Varanasi in India, Mandalay in Myamar, Chongqing and Nanjing in China, Nagoya in Japan and finaly Honolulu in Hawaii USA on Friday July 3rd.
Solar Impulse 2 voyage came to a temporary stop in Honolulu Hawaii, due to damaged batteries. New batteries are ordered, once delivered they will be installed and tested before long flights can be resumed, therefore Solar impulse 2 will not resume its around the world flight before April 2016 to benefit from longer days in the northern hemisphere allowing for multi days solar powered flights.
In its last flight leg from Japan to Hawaii, Solar Impulse 2 continued setting new world records. Other than being the first ever oceanic crossing made by a solar airplane; arriving on July 3rd the flight leg recorded flight duration of 4 days 21 hours and 52 minutes covering a distance of 7,212 km and reaching a maximum altitude of 8,634 m.
For Solar Impulse’s Founders, the Pacific crossing represents a testament to the 12 years of hard work that Solar Impulse has achieved since its inception.
The cross Pacific leg represented a new challenge: The pilot own physical endurance. See how the pilot will live in a small cockpit for days in a row, how he will operate the plane and manage difficult weather conditions.
The following article from Spiegel online is dated July 9, 2015
(The above text was composed from various sources from Solar Impulse website and Wikipedia).