Engineers at SolarStratos are building a plane that will fly higher than any other manned solar-powered aircraft. They’re shooting for 80,000 feet (24km) - high above the clouds and well into the Earth’s stratosphere.
A Scientific Mission and More
Unlike the Solar Impulse, which is designed for long-duration flight, the SolarStratos is going for altitude. More than just a novelty aircraft, the SolarStratos team envisions a plane that can be used for scientific purposes. With zero-emissions, the plane can take sensitive atmospheric measurements without contaminating the samples with its own exhaust, much like the solar powered MS Tûranor ship does with ocean measurements.
In addition to its scientific capabilities, the SolarStratos is a two-seater, making it a potential tourist attraction. I’d imagine that there are a few wealthy individuals who would pay the 50,000 Euros ($69,000 US) for a high-flying adventure on this plane. While “outer space” is closer to 100km, the SolarStratos’ will take you to where the stars are visible during the day and the Earth’s curvature is obvious. It’s not microgravity, but it’s a heck of a view!
Specifications
With a length of 7.7 meters and a 20 meter wingspan, the 350 kg SolarStratos is powered by a 13.5kW (18hp) electric motor that drives its single propeller. (For comparison, my relatively small riding lawnmower has a 17hp engine.) The plane sports 20m2 of solar panels with 24% efficiency and a 20kWh battery pack, so technically it’s a battery-assisted solar powered aircraft. At full sun - and it’s always a sunny day when you’re 24km above the ground - the panels generate nearly 5kW of power. My “back of the envelope” calculations suggest that the batteries will be fully depleted during the four-hour ascent stage - and that's with the solar panels providing energy as well - so at cruising altitude, where the motor doesn’t need to run at full power, the plane will indeed run exclusively on solar energy.
The SolarStratos is the brainchild of Calin Gologan, founder and CEO of PC-Aero. It’s not surprising, then, that the plane is a modification of PC-Aero’s one-seat Elektra-One Solar. The SolarStratos design has less weight than the Elektra-One and adds room for a passenger.
Spacesuits Needed
Because the air is thin and the cabin is unpressurized, the pilot and passenger will need to wear spacesuits similar to those worn by astronauts. (The equipment needed to pressurize the cabin would increase the weight of the aircraft.) SolarStratos is talking with companies that make spacesuits in order to develop a low-power, lightweight suit - the world’s first spacesuit powered by sunlight. A lighter spacesuit could become spin-off technology that works its way to NASA instead of from NASA - you never know!
Down-to-Earth Price Tag?
No estimates on the cost of the SolarStratos, but the PC Aero Elektra-One currently sells for about $105,000, which is less than the price of a low-end Cessna. Solar-electric airplanes are now feasible, not only technically, but also economically. The SolarStratos will provide valuable lessons for aircraft designers, which could help the entire industry rise above its fossil-fueled competitors. We'll probably never see solar powered jetliners, but for small aircraft flown by weekend pilots, the sun could be the fuel of choice in the near future.
The SolarStratos team expects to take flight sometime in 2017. Here's their video:
Images and Video courtesy of SolarStratos