The entire journey was broken down into 17-stages that covered a distance of more than 42,000 km (26,000 miles). The flight path crossed four continents, three seas, and two oceans, beginning and ending in the United Arab Emirates. The longest leg of the expedition took place between Nagoya, Japan and Hawaii, covering some 8924 km (5545 miles) of Pacific Ocean in the process. That stage alone took 118 hours to complete, giving pilot Andre Borschberg the record for the longest solo flight.
Throughout the flight Borschberg split time at the controls with fellow pilot Bertrand Piccard, who was at the helm of the Solar Impulse when it made the final flight from Cairo, Egypt to Abu Dhabi yesterday, bringing an end to the 17-month odyssey that proved clean energy can be used to power an aircraft. The two pilots has hoped to complete the journey in a much shorter timeframe however, but a catastrophic failure of the aircraft's battery system caused it to be grounded for 10 months while repairs and upgrades were made.
The Solar Impulse has a wingspan of over 72 meters (236 ft), which is larger than even a 747 commercial aircraft. Those wings contain more than 17,000 individual solar cells, which collect power and store it in onboard batteries. Those batteries can than be used to power the aircraft even at night.
While this was an impressive demonstration of technology and the steps being taken to improve the use of clean energy, don't expect the Solar Impulse to have a dramatic impact on the commercial aviation anytime soon. Solar cells will need to improve their efficiency drastically before that can happen, as it is currently impossible to power a large aircraft using just the light of the sun. Still, this is a step in the right direction, show us a potential future where clean aircraft could whisk passengers off to remote destinations without having a dramatic impact on the environment. While that vision is still in the distant future, it is good to know that we're taking small steps towards making it a reality now.