“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)

Belarussian policemen detain a woman in central Minsk on August 11, 2020. Thousands of opposition supporters who also protested the results met with a tough police crackdown in Minsk and several other Belarusian cities for two straight nights. (Photo by Uladz Hrydzin/Radio Free Europe/Radio Liberty)

A French Bulldog named Nord Boss stands an the back of his owner Natasha while they skateboard in the Sokolniki Park in Moscow, Russia on October 14, 2020. (Photo by Evgenia Novozhenina/Reuters)

Gabriel Berendo, a businessman and car enthusiast, drives a casket converted into a car on Sunday May 31, 2020 in Cebu city, central Philippines as he goes around streets to remind residents to stay at home as lockdown measures to prevent the spread of the new coronavirus eases next week. (Photo by AP Photo/Stringer)

A woman takes photographs of falling snow from a window during a heavy snowfall, amid the coronavirus disease (COVID-19) pandemic in Seoul, South Korea, January 12, 2021. (Photo by Kim Hong-Ji/Reuters)

Social activists working for the rights of sеx workers celebrate with colour powder during the International Sеx Workers' Rights Day in Kolkata on March 3, 2020. (Photo by Dibyangshu Sarkar/AFP Photo)

Fabian Ramirez, 11, scavenges a trash container for vegetables with his family that were discarded at the “Mercado de Abasto”, a market for vendors, during the fourth week of a quarantine to help contain the spread of the new coronavirus in Asuncion, Paraguay, Thursday, April 2, 2020. (Photo by Jorge Saenz/AP Photo)

A model rehearses with a fabric face mask on, designed by Zhou Li for her Autumn/Winter 2020 collection show, during China Fashion Week in Beijing, following the novel coronavirus disease (COVID-19) outbreak, China on May 3, 2020. (Photo by Tingshu Wang/Reuters)