( CNN ) The Solar Impulse 2 , the experimental plane attempting to fly around the world without using a drop of fuel , has been grounded by the weather in China . What was supposed to be an overnight pit stop in the southwestern city of Chongqing has now stretched into a two-and-a-half week stay . It 's an unexpected layover that is testing the patience of the pilots and more than 60 team members , just a quarter of the way along a journey that will cover some 35,000 kilometers ( 21,748 miles ) over five months . `` You can believe that your will can influence the weather , '' says pilot Bertrand Piccard , who comes from a long family line of explorers . But `` then you 'll be really disappointed because it does n't work . `` Or you just know that it 's an adventure you do with the forces of nature . '' Piccard , along with Andre Borschberg , a Swiss engineer , are taking turns flying the single-seater aircraft , which took off from Abu Dhabi on March 9 and has successfully flown through Oman , India , and Myanmar . There is much at stake . Their mission , which the pilots say is aimed at proving the power of renewable energy , and inspiring innovation , has been 12 years in the making . In many ways , it has become Piccard and Borschberg 's raison d'etre . But so far , the Solar Impulse 2 has been spending a lot of time on the ground . The latest setback came when a Thursday takeoff was canceled , because the cross winds in Nanjing , the plane 's destination , were forecast to be too strong around its expected landing time . Because of its weight , at just 2,300 kilograms -- about the same as a large SUV -- the aircraft needs near perfect weather conditions , including cross winds of less than 4 knots , or about 7 kilometers an hour , in order to fly . While the team is used to waiting , they are clearly eager to move on . `` Our boss is the sun , '' says Solar Impulse spokeswoman Claudia Durgnat . Durgnat says there may be a tiny window ahead , with the next possible departure from Chongqing on Tuesday . `` It 's not good before , and the days after do n't look very clear . '' Even with the delay , Durgnat says , the plane technically is n't behind schedule . That 's because the team needs to wait until the end of the month for the northern hemisphere days to get longer , before the plane can venture across the Pacific Ocean to Hawaii . With more than 17,000 solar cells along the tops of its wings and fuselage , the Solar Impulse 2 stores up energy during the day , in order to power the motors that carry it through the night , typically at speeds no faster than a car on a highway . Inside a specially constructed tent at the end of the runway at Chongqing International Airport , a skeleton team of less than a dozen people works to complete the day 's tasks . The rest of the crew has been waiting for weeks in Nanjing . Even with the extended stay , no time is wasted . Piccard spends a few hours of the afternoon in the cockpit , training to prepare for the Solar Impulse 's crossings over the Pacific and Atlantic Ocean , what the team calls `` the moment of truth . '' The plane will then return to Abu Dhabi , where it had taken off . Nearby , two technicians repair a couple of the flight computers , which display critical information in the cockpit , punching extra holes in their casings so they do n't overheat . Meanwhile , Borschberg has returned to Switzerland to rest and get medical treatment for a migraine and a skin condition . The team expects him back in China early next week . Borschberg is still scheduled to fly first leg of the Pacific crossing , which could last up to five days and nights . `` The airplane is ready . The mission control center is ready . We 've been waiting for that moment since so long , '' says Piccard . Borschberg and Piccard , who piloted an earlier version of the plane across the U.S. in 2013 , are no strangers to adventure . Borschberg is a former fighter pilot , and Piccard was part of the first team to circumnavigate the earth nonstop in a balloon in 1999 .
Solar plane attempting to be first to circumnavigate world without using fuel is stuck in China . Score: 6