Solar planes have already traversed the Alps and flown around the world, but one team has its sights set a little higher: the edge of space. SolarStratos is planning to fly a solar-powered plane to an altitude of over 80,000 ft (24,000 m), from where the curvature of the Earth as well as daytime stars will be visible.

The aim of the project is to demonstrate the potential of renewable energy and to explore the possibility of flying people to such altitudes using solar technology. Although it began in 2014, it has hit a significant milestone this month with the completion of the hangar that will serve as the team's operational base, in which the SolarStratos plane will be developed and maintained and from where testing will be carried out.

The plane has been built by electric- and solar-aircraft firm PC-Aero, which was behind the Elektra One plane, and its solar systems have been developed by the Swiss Center for Electronics and Microtechnology. It is said to be the first commercial two-seater solar plane in history and the first that will reach the stratosphere. It measures 8.5-m (27.9-ft) long, has a wingspan of 24.9 m (81.7 ft) and weighs in at just 450 kg (992 lb).

There are 22 sq m (237 sq ft) of solar panels covering the plane that power a 32-kW electric engine and charge a 20-kWh lithium-ion battery. These will apparently allow the plane to stay airborne for over 24 hours, although its inaugural flight is slated to be a little shorter, clocking in at five hours – two to ascend, 15 minutes to look around, and three hours to descend.

To save weight during the flight, the plane will not be pressurized. Instead, pilot Raphaël Domjan will wear a pressurized suit, like those worn by astronauts. As the suit will be connected to and powered by the plane, it will not allow him, should the need arise, to eject or to use a parachute. Among the factors at play will be temperatures as low as 70 °C (-94 °F) and atmospheric pressure of around 5 percent that on Earth.

Domjan apparently had the idea for the SolarStratos project during the Atlantic crossing of his PlanetSolar boat's round-the-world journey. The hangar and the plane are due to be publicly launched on December 7th, with test flights scheduled to begin early next year. The mission itself is currently set for 2018.

The exceptionally well-done video below provides an idea of what the journey will be like.

Source: New Atlas, SolarStratos