Solar Impulse 2, the aircraft attempting to circumnavigate the world fueled only by sun power, will be grounded in Hawaii until next April for battery repairs. On July 3, the plane completed the longest leg of its global flight – a record-breaking (non-stop, solo piloted) five-day, five-night journey from Nagoya, Japan, to Hawaii – during which its storage batteries overheated, sustaining “irreversible” damage, according to a statement from the team.
The route from Japan was piloted by Andre Borschberg. Following several days of essential repairs, it was planned for Betrand Piccard to command the next stage of the journey to Phoenix, Arizona. Maintenance checks indicated that the temperature of the batteries during quick ascents and descents in a tropical climate was “not properly anticipated.” The aircraft is now housed in a University of Hawaii hangar at the Kalaeloa airport on Oahu while repairs are made.hangar in Hawaii while the engineering team researches options for improved cooling and heating. The remainder of the journey has been suspended until 2016.
“The damage to the batteries is not a technical failure or a weakness in the technology,” the team said. “Setbacks are part of the challenges of a project which is pushing technological boundaries to the limits.”
Although Solar Impulse 2 has a wingspan larger than that of a Boeing 747, equipped with 17,000 solar cells that power its four electric motors – the aircraft only weighs about 5,000 pounds – as much as a minivan. The solar cells recharge lithium batteries that allow the plane to fly at night.
The battery problems were not the first project setback. Weather problems delayed the first leg of the Pacific flight, and after finally taking off from Nanjing, China, in May en route to Hawaii, the plane landed in Nagoya, Japan after high winds damaged a wing.
The Solar Impulse team said in a news release that there was no weakness with the technology, but the team didn’t anticipate temperature fluctuations associated with rapid altitude changes in a tropical climate. They will continue the attempt to circumvent the globe.
“Solar Impulse is attempting a historic first of flying around the world only on solar energy,” the pilots said in a statement. “And while Solar Impulse has completed eight legs, covering nearly half of the journey, setbacks are part of the challenges of a project which is pushing technological boundaries to the limits.”
The 13-leg journey started in Abu Dhabi in the United Arab Emirates in early March. Stay connected to up-to-the-minute status at the Solar Impulse website (link here).