The eagle has landed. And the “eagle” in this case is a solar-powered airplane. The Solar Impulse 2 (Si2) — part of Solar Impulse, a program that aims to demonstrate and promote the power of clean technologies — touched down in Mountain View, Calif., on April 24, and just in time for Earth Day weekend. It was the final stage of a pioneering flight that began in early March 2015. Swiss explorer Bertrand Piccard manned this final leg of the approximately 22,000-mile trip that left the Kalaeloa Airport in Hawaii on April 21, where it had been since last summer after batteries on the aircraft overheated and needed repair; new cooling and heating systems were installed before the Si2 flight resumed. The April 21 takeoff was almost delayed after the Monaco Mission Control Center (MCC) — a team of engineers organized and trained by Solar Impulse co-founder and CEO André Borschberg, a Swiss engineer and Si2 pilot — alerted the Solar Impulse team to potentially strong winds along the path to California; MCC was monitoring the trip. According to information from Solar Impulse, “to everyone’s great relief, the wind died down after a while,” allowing Si2 to leave the airport hangar and take to the skies on time. Si2 weighs about as much as a car, and has a wingspan wider than a 747. Those wings are covered with just over 17,000 solar cells that power four propellers and recharge four lithium polymer batteries, which allow the plane to fly at night. It is able to reach altitudes of about 28,000 feet and a top speed of about 60 mph. It was smooth sailing over the Pacific Ocean through Earth Day on April 22. This was also the day that 175 countries signed the Paris Climate Agreement, of which Piccard is a huge supporter. “[The Paris agreement] is the launch of the clean technology revolution,” he said, speaking live from the cockpit with U.N. Secretary-General Ban Ki-moon and representatives of those countries just hours after the signing. Si2 made its way over San Francisco’s Golden Gate Bridge on April 23, where Piccard was joined in the air briefly by Borschberg; he was snapping photos from a helicopter alongside the solar-powered aircraft. This was the second time the pair flew side by side this way — several years ago, they successfully flew Si2’s predecessor, the Solar Impulse 1, across the U.S. Si2’s trailblazing adventure began last year, when Borschberg left Abu Dhabi in the United Arab Emirates on March 9. His was the longest leg of the trip, and included several stops before reaching Hawaii. Piccard’s portion of the flight went straight through from Hawaii to California. Following Piccard’s successful landing, Si2 will take to the skies again — across America to New York before making the Atlantic crossing to Europe and then returning to Abu Dhabi. The Solar Impulse program, launching projects such as the Future is Clean initiative that encompasses international organizations, business leaders and academia, will continue its work toward the goal of promoting the implementation of new, clean technologies that could simultaneously reduce CO2 emissions and stimulate economic growth. This program brings to light the many possibilities presented by solar power, and it presents a sunny outlook for the future. “If an airplane like Solar Impulse 2 can fly day and night without fuel,” Piccard said, “the world can be much cleaner.”