On the edge of an industrial estate in Yverdon-Les-Bains, Switzerland, a small team of adventurers is preparing for a mission to the edge of space.

If they succeed, their solar-powered aircraft will fly higher than any plane before it and show that renewable energy can not only match fossil fuels but surpass them.


"Our goal is to be the highest plane ever, not only solar and electric," says Raphaël Domjan, 44, initiator and pilot of SolarStratos. Echoes of Bertrand Piccard are everywhere: both are Swiss, both are based near Lausanne and both believe adventure can inspire people to take action to tackle climate change.

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"With this project we take technology you can find in the supermarket and we push it to the limit," Domjan says. If a solar-powered plane can take a human being to the edge of space and back, he continues, it could send a strong message about the potential of clean technology. "We still have so many things to explore. Maybe exploration can be used to protect our planet."

Domjan's mission is a daring one. In late 2018 he plans to climb into SolarStratos and take two hours and 30 minutes to ascend to 25,000m. There, on the edge of space, he hopes to spend 15 minutes in the stratosphere before slowly spiralling back down to Earth. He will do so without using any fuel. "It's like the Icarus flight," Domjan jokes. "But I hope I will not lose my wings."



Founded in March 2014, SolarStratos has already raised $5 million (£3.8m) from sponsors and work is underway to manufacture the experimental aircraft. A further $5 million will be required to get the mission off the ground. Solar-powered aviation specialist PC-Solar is expected to deliver the aircraft by the end of 2016.



Everything about the project is incongruous: Domjan is understated and quiet; he wears a bomber jacket with a SolarStratos patch on the arm, his hair gelled into spikes. His office in the Y-Parc incubator is flanked by software firms and app startups.


Domjan at the SolarStratos HQ in Yverdon-Les-Bains; a 500m2 hangar is being built at nearby Payerne Aorta

Domjan, who previously worked as a mechanic and paramedic, now dedicates his life to exploring and promoting clean technologies. In 2012 he completed the first circumnavigation of the globe in a solar-powered boat dubbed PlanetSolar. In 2003, he coated the roof of his parents' house in solar panels and founded a solar-powered web-hosting company.

It was his work as a mountain guide that inspired his fascination with solar energy. "When I was in Iceland for the first time, in 1993, we stayed next to a big glacier," says Domjan, searching on his computer for a picture he took. "When I came back 11 years later, the glacier wasn't there any more."

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The finished SolarStratos aircraft will weigh 450kg and be coated in 22m2 of solar panels. Its wings will measure 24.8m across and it will have just two seats. But for his record-breaking attempt into the stratosphere, Domjan will be completely alone. SolarStratos's two 19kW motors produce around 50 horsepower, the same amount as a small scooter. To get up to 25,000m they need all the help they can get. Domjan himself will have to lose ten kilos before take-off. "We have to be careful with the weight, it's a big, big challenge," Domjan says.

Another big challenge: keeping Domjan alive. At 25,000m there is two per cent of the oxygen available at sea level, temperatures plummet to -70°C and air pressure falls to 0.019 atmospheres. At these altitudes Domjan will have to wear a pressurised spacesuit to keep him alive. Russian spaceflight specialist Zvezda will develop a specially adapted, lightweight suit for the mission. The suit, costing around $1 million, is being donated to SolarStratos free of charge.

" We can change and we can be optimistic. It could be a huge opportunity for mankind to change; to use what we get from the sky for free" Raphaël Domjan, SolarStratos


Although most parts of the plane will be off-the-shelf, some parts are being developed from scratch. Austrian battery firm Kreisel Electric is working on an experimental 20kWh lithium-ion battery that can operate safely in the harsh stratospheric conditions. "If we have a problem with the battery in the stratosphere, it's finished," says Domjan, nervously. If the mission goes as planned, SolarStratos will take off and land with its batteries almost fully charged using only solar energy.



The first test flight is scheduled for the end of the year. In the second half of 2017, SolarStratos plans to make its first record-breaking attempt: to climb above 9,420m, the highest altitude achieved by Piccard's Solar Impulse. But Domjan doesn't intend to take this flight alone. "My goal is to make this flight with [Piccard] on board. I think that could be a nice message," says Domjan of his friend. "We are not in competition."

Although Solar Impulse has completed its round-the-world flight, for SolarStratos there remain many unknowns: can it raise the extra $5m it needs? Will the battery hold? How will the plane operate in the stratosphere? If successful, Domjan has ambitions to turn SolarStratos into either a specialist solar-powered drone manufacturer to compete with the likes of Facebook's Aquilla programme or, more ambitiously, to launch a solar-powered stratosphere-tourism business.

"Our aeroplane will be the first step before the commercial stage," he explains. The plan is to construct a three-person, solar-powered aeroplane with a pressurised cabin and start operating commercial flights with one pilot and two paying customers by 2021. "You need much more power. It's a big challenge. Much more difficult, much more expensive." And Domjan's potential SolarStratos tourism venture won't be alone: Zero2Infinity, Space Vision and WorldView are all working on stratospheric balloon rides priced at between $75,000 and $120,000.



"The goal is to be cheaper than the balloon," he says. The company is already offering those willing to pay $60,000 a chance to fly into the edge of the stratosphere in the first SolarStratos plane, though nobody has stumped up yet. But Domjan is hopeful that whisking more people to the edge of space using solar power alone can be a powerful tool for promoting clean technologies. "We can change and we can be optimistic," he says, echoing Piccard. "It could be a huge opportunity for mankind to change, to use what we get from the sky for free."