Aircraft

Chocks away: Official debut for solar-powered space plane

Chocks away: Official debut fo...
The SolarStratos plane and operational hangar were unveiled at an event in Payerne, Switzerland, on December 7
The SolarStratos plane and operational hangar were unveiled at an event in Payerne, Switzerland, on December 7
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The SolarStratos plane and operational hangar were unveiled at an event in Payerne, Switzerland, on December 7
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The SolarStratos plane and operational hangar were unveiled at an event in Payerne, Switzerland, on December 7
The SolarStratos plane will fly to an altitude of 25,000 m (82,000 ft)
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The SolarStratos plane will fly to an altitude of 25,000 m (82,000 ft)
22 sq m (237 sq ft) of solar panels charge the SolarStratos plane's 20 kWh battery pack
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22 sq m (237 sq ft) of solar panels charge the SolarStratos plane's 20 kWh battery pack
The SolarStratos plane weighs 450 kg (992 lb)
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The SolarStratos plane weighs 450 kg (992 lb)
The SolarStratos plane is 8.5-m (27.9-ft) long
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The SolarStratos plane is 8.5-m (27.9-ft) long
The SolarStratos plane will be flown by Raphaël Domjan
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The SolarStratos plane will be flown by Raphaël Domjan
For the SolarStratos mission, Raphaël Domjan will wear a pressurized suit that will be connected to the plane and powered by its solar panels
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For the SolarStratos mission, Raphaël Domjan will wear a pressurized suit that will be connected to the plane and powered by its solar panels
SolarStratos test flights are due to being in January 2017 and the mission itself is currently scheduled for 2018
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SolarStratos test flights are due to being in January 2017 and the mission itself is currently scheduled for 2018

A solar-powered plane that is to be flown to the edge of space has been officially unveiled today. The SolarStratos plane is powered by 22 sq m (237 sq ft) of solar panels and will be flown to an altitude of 25,000 m (82,000 ft) to demonstrate and explore the potential of the technology.

"Our goal is to demonstrate that current technology offers us the possibility to achieve above and beyond what fossil fuels offer," says project founder and pilot Raphaël Domjan in a press release. "Electric and solar vehicles are amongst the major challenges of the 21st century. Our aircraft can fly at an altitude of 25,000 m and this opens the door to the possibility of electric and solar commercial aviation, close to space."

The solar-electric plane is said to have an environmental footprint that is equivalent to that of an electric car and is aimed at offering an alternative to using large quantities of energy or helium as a means of reaching the stratosphere. It is 8.5-m (27.9-ft) long, has a wingspan of 24.8 m (81.4 ft) and weighs in at just 450 kg (992 lb).

The solar panel array charges a 20 kWh lithium-ion battery, which powers a 32-kW electric motor that in turn drives a 2.2-m (7.2-ft) propeller. SolarStratos says it is able to fly continuously for over 24 hours, which is more than enough to cover the expected two-and-a-half hours it will take to reach space, 15 minutes cruising at peak altitude and three hours to return to the Earth.

The SolarStratos plane weighs 450 kg (992 lb)
The SolarStratos plane weighs 450 kg (992 lb)

The project began in 2014, after Domjan had the idea during the solar-powered boat crossing of the Atlantic on his PlanetSolar round-the-world journey. Beyond the project's demonstrative and exploratory tech goals, it is hoped that it will inspire people and to help uncover new scientific knowledge.

The SolarStratos plane and operational hangar were unveiled at an event in Payerne, Switzerland, to around 300 guests, including ambassadors, partners, government representatives and members of the media.

The project is currently in the development phase, but the first roll tests, touch-and-go landings and test flights are due to take place in January next year. All being well, medium-altitude flights will follow later in the year and initial stratospheric flights in 2018. The mission itself is also scheduled for 2018.

Source: SolarStratos

8 comments
alan c
I think a solar 'plane should have a high wing and a tee-tail so that the panels are not shaded by the airframe.
Bob Flint
Why would it take 3 hours to come back down when it takes 2.5 hours to get up?
Douglas Bennett Rogers
I have been looking for this for a long time! With a little more work, it should be able to stay up and work like a cheap satellite.
Bob
The Helios unmanned plane flew higher but had a 247 foot wingspan and the wing loading of a paper plane. This plane just looks like an extended wing sailplane and will require a much much higher speed to stay aloft. I would also think that the propeller and control surfaces would have to be rather large for control and the plane could very well break up trying to recover from a high speed stall. Being a two seater doesn't sound right either. Carrying the extra weight of a passenger to this altitude doesn't make sense. Just the power to heat another spacesuit and enough oxygen for two with no way to eject sounds like a very risky project. It says the plane has already been built. I hope it can fly half as high as the advertising hype.
SamB
@Bob Flint The plane is designed to generate large amounts of lift at relatively low speed. When you are going down you are constantly fighting those lift generating forces while trying to keep the plane in controlled flight. That is why it takes longer for this plane to descend than to climb.
MD
@SamB Is that right?? 82000ft = 164 minutes of descent at a "standard" 500ft/min descent. So 2.7 - 3 hours just sounds like a ballpark figure for flight planning. Ascent in 2.5 hours = 546.67ft/min That is likely the AC's max climb rate (at somewhere between 45-60kt) In an aircraft designed for lift and efficiency, if you push the nose down gravity takes over and the speed will quickly exceed "normal operating speed", with no speed brakes the only way to control this is by pushing down more gently (lower descent rate). Nothing to do with "fighting those lift generating forces" while maintaining control. Well, exceeding Vne, or Vturb can have significant "controlled flight" consequences, under extreme circumstances.
jon999
Check out the Perlan Project. They are planning on flying even higher, with no motor! The aircraft is currently making test flights.
habakak
@BobFlint....Bobby, ALL solar planes suffer from this phenomenon. On the way up the plane gets closer to the sun, so it generates more power from those solar panels. On the descent, it works the opposite way. It moves away from the sun and thus loses power and speed. You are welcome.