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Solar-power vehicles pushing boundaries of possibility

  • Plane sailing
    With a 208-ft (63-m) wingspan, Solar Impulse is the first airplane that can fly day and night without fuel or polluting emissions. (Copyright: Getty Images)
  • Coast to coast
    Solar Impulse successfully crossed the US, making the trip from San Francisco to New York in five stages. (Copyright: Reuters)
  • Global achievement
    In 2012, the world's largest solar-powered boat, the Turanor PlanetSolar, became the first solar-powered vessel to travel around the world, in 584 days. (Copyright: Getty Images)
  • Floating lab
    PlanetSolar has just completed a three-month voyage across the Atlantic Ocean to study how the Gulf Stream and climate change can influence each other. (Copyright: Getty Images)
  • Speed demon
    Sunswift IVy from the University of New South Wales is the fastest solar-powered car, reaching a speed of 55.077 mph (88.738 kph) in 2011. (Copyright: Sunswift).
  • Reach the heights
    Nasa’s Helios reached a record altitude for a non-rocket powered aircraft of 96,863 ft (29,524m), in 2001, but broke apart in flight two years later. (Copyright: Nasa)
  • Drone alone
    The aircraft endurance record goes to QuinetiQ’s drone Zephyr, which in 2010 made a non-stop flight of 336 hours and 22 minutes. That’s just over 14 days. (Copyright: QuinetiQ)
  • Going the distance
    The US military has been running programmes, such as Vulture, to develop unmanned aircraft that can stay aloft for five years. (Copyright: Aurora Flights Sciences)
  • Out of this world
    For more ambitious ideas how about SPS-Alpha – which aims to assemble a huge bell-shaped structure for solar power in space. (Copyright: Mark Elwood, SpaceWorks Enterprises, Inc.)
A new wave of aircraft and vehicles at the cutting edge of technology are making epic journeys around the world relying only on the power of the Sun.

The promise of fleets of clean, green transport powered by solar energy has for decades just been that: a promise. But a new wave of vehicles is pushing the limits of what’s possible.

The Solar Impulse plane has just successfully crossed the US in five stages – from San Francisco to New York. And the world’s largest solar-powered boat, the Turanor Planet Solar, not only circumnavigated the globe in 2012, it also made the fastest solar-powered crossing of the Atlantic in May this year. The Atlantic trip was completed in 22 days, shattering its own previous record by four days.

There are more record-breaking feats in the pipeline. For instance, the team behind Solar Impulse aims to build a craft that will circumnavigate the world in 2015 – and to do so will require the development of new materials and construction methods, says the team, such as electrolytes that increase the energy density of batteries. Not to mention competitions like the World Solar Challenge, which takes place in October, where competitors have to complete a 3,000 km (1,860 miles) race from Darwin to Adelaide in Australia.

But for now, here’s a selection of the fastest, highest and furthest vehicles have gone, and possibly can go, when powered only by the Sun.

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