The pilots' most recent dispatches, which can be followed at the Solar Impulse website (see link below), had the solar-power aircraft cruising at about 20,000 feet over a cold northern Pacific.
"From this point onwards, [Pilot] Bertrand Piccard will only be moving forward with Si2," the dispatch said.
Solar Impulse 2 is scheduled to land in Mountain View, Calif. on Saturday. Piccard's co-pilot is Andre Borschberg.
The experimental aircraft started its journey in March 2015 from Abu Dhabi, the capital of the United Arab Emirates, and made stops in Oman, Myanmar, China and Japan. It's on the ninth leg of its circumnavigation.
It had been grounded in Hawaii since July 2015, after its battery system sustained heat damage on its trip from Japan.
In another dispatch, Piccard said landing at Mountain View, the heart of Silicon Valley and the home of Google, Apple and scores of other tech firms will be a fitting conclusion to this particularly challenging leg of the Solar Impulse's journey, the site being "in the middle of the pioneering spirit."
For those wondering how such a journey is possible, the wings of Solar Impulse 2 have been fitted with 17,000 solar cells that not only power the aircraft by day, but also charge the batteries that the crew depends on at night to keep the mission going.
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