Sunset is seen through smoke from the Wallow fire June 8, 2011 in Springerville, Arizona. Hundreds of thousands of acres have burned in eastern Arizona prompting evacuations by residents. Smoke loomed over the twin towns of Eager and Springerville, home to about 7,000 people north of the fire. (Photo by Eric Thayer/Getty Images)

“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

Who Left The Tap Running by artist Simon McGrath is seen as part of the Sculpture by the Sea outdoor exhibition along the Bondi to Bronte coastal walk on November 4, 2011 in Sydney, Australia. (Photo by Lisa Maree Williams/Getty Images)

A woman walks past the barbed wire separating Belarusian servicemen and Belarusian opposition supporters during a rally in Minsk, Belarus, Sunday, August 30, 2020. Tens of thousands of demonstrators have gathered in the capital of Belarus, beginning the fourth week of daily protests demanding that the country's authoritarian president resign. The protests began after an Aug. 9 presidential election that protesters say was rigged and officials say gave President Alexander Lukashenko a sixth term in office. (Photo by Tut.By via AP Photo)

A woman jumps out of a street art object in the center of the Ukrainian capital of Kiev during a warm autumn day on September 25, 2020. (Photo by Sergei Supinsky/AFP Photo)

(L-R) Pieter Van Lankveld, Jay Schippers, Ynze Oegema, Justin Kimmann, Teun Kivit and Twan Van Gendt compete during the Dutch National BMX Championships at Olympic Training Centre Papendal on October 11, 2020 in Arnhem, Netherlands. (Photo by Dean Mouhtaropoulos/Getty Images)

A worker sprays disinfectant at Independence Square during a disinfection operation, amid the coronavirus disease (COVID-19) outbreak in Kuala Lumpur on October 17, 2020. (Photo by Lim Huey Teng/Reuters)

Robots made by local enthusiasts and employees of an automobile repair workshop are seen during installation works on the outskirts of the rebel-controlled city of Donetsk, Ukraine, November 26, 2020. According to creators, who plan to open a robotics engineering park, 13-metre and 6-metre-high sculptures featuring transformer robots were made of waste metal including car components and weigh about 4 and 2 tonnes respectively. (Photo by Alexander Ermochenko/Reuters)