“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)

A Burmese monk feeds the seagulls at a Yangon river jetty February 8, 2012 in Yangon, Myanmar. (Photo by Paula Bronstein/Getty Images)

In this January 16, 2019, file photo, a homeless man sleeps on a median strip in New Delhi, India. In India, some 270 million people – nearly 22 percent of the country's population – live in poverty, making giveaways particularly attractive to voters. The Modi government in its interim budget in January announced farmers would be paid 6,000 rupees ($85) annually, benefiting as many as 120 million households and income tax relief to the middle class. (Photo by Altaf Qadri/AP Photo/File)

Parade goers during Brighton Pride Parade on August 03, 2019 in Brighton, England. Tens of thousands of revellers dressed in rainbow colours and elaborate costumes and descended on the seaside city to ask for equality for all. (Photo by Tristan Fewings/Getty Images)

Models backstage ahead of the Etam Winter 2019/Summer 2020 show as part of Paris Fashion Week At Roland Garros on September 24, 2019 in Paris, France. (Photo by Rex Features/Shutterstock/SIPA Press)

An official (R) measures the size of a whale shark (Rhincodon typus) carcass on the shore of Teluk Betung beach in West Sumatra, Indonesia, 08 October 2019. The dead whale shark washed ashore at Teluk Betung beach on 07 October 2019. (Photo by Rajo Batuah/EPA/EFE)

Manuelle aka the Snake Woman poses for photographs with a beer as she promotes the fnnual Beer Festival Oktoberfest in Cologne, Germany on September 22, 2014. (Photo by Federico Gambarini/EPA/EFE/Rex Features/Shutterstock)

A barber cuts hair of his client at a shuttered market during the countrywide traders strike in Lahore on October 29, 2019. Pakistani traders have joined hands to observe a nationwide shutterdown strike against the government over its “anti-business” policies, seeking to bring trade and economic activities across the country to a standstill on October 29 and 30. (Photo by Arif Ali/AFP Photo)