The Solar Impulse team announced that the completion of its round-the-world solar flight will now be postponed until next April. The batteries of the Solar Impulse 2 solar-powered aircraft sustained damage as the aircraft ascended to an optimal energy-management altitude of 28,000 ft (8,534 m) on the first day of its ambitious Japan-to-Hawaii flight. It is believed that a high rate of climb coupled with over-insulation of the gondolas resulted in irreversible overheating damage to the aircraft's batteries.
Whilst the aircraft was able to safely reach its destination, the incident represents a serious setback to the endeavor, which thus far has been a story of triumph andhardship. The team states that the failure was not a technical or design issue, but rather an evaluation error in accessing battery cooling requirements in the tropical climate. In the context of the ambitious design and scope of the project, technical delays such as those currently being experienced were foreseeable, if not on some level inevitable. Yet, despite these setbacks, Solar Impulse 2 has achieved remarkable milestones in the aviation sphere.
Even on the five-day flight to Hawaii on which it sustained the catastrophic battery damage, the aircraft managed to make its mark in the history books, smashing the record for the longest distance and duration for a solar aviation flight, and setting the record for the longest-ever solo flight of any kind. Not bad for an experimental aircraft with a wingspan greater than that of a Boeing 747-8I, built largely from materials lighter than paper, and four engines powered by 17,248 solar cells.
It is expected that the Solar Impulse 2 will remain at a hangar in Kalaeloa Airport, Hawaii, as the team makes repairs to the airplane. Should the refit go without a hitch, the aircraft will take to the skies in early April as the team attempts to continue its epic migration, with the next port of call situated on the west coast of the US.