“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)

Two young women pose for a portrait, dressed in robes after collecting their Bachelor degrees in Conakry on October 12, 2020. Presidential elections are to be held on October 18, with incumbent President bidding for a third term in office, defying critics who say he forced through a new constitution this year enabling him to sidestep two-term presidential limits. (Photo by John Wessels/AFP Photo)

Residents of the Santa Marta favela, Botafogo, south zone in Rio de Janeiro, Brazil unite to sanitize the community and fight the advance of the new coronavirus this Saturday, November 28, 2020. (Photo by Ellan Lustosa/ZUMA Wire/Rex Features/Shutterstock)

After a long time renovation project, the old town in Taiyuan city which was founded in 1357, finally lights up and opens to public in Taiyuan City, north China's Shanxi Province, 23 November 2020. (Photo by Rex Features/Shutterstock)

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)

Buddhist monk Wilatha holds a rescued Burmese python at his monastery that has turned into a snake sanctuary on the outskirts of Yangon, Myanmar, November 26, 2020. Wilatha is trying to play a part in saving scores of snakes that might otherwise be killed or destined for the black market. (Photo by Shwe Paw Mya Tin/Reuters)

A Chicago Police Officer runs toward gunfire as looters break into downtown stores in the early hours of the morning on August 10, 2020. (Photo by RMV/Rex Features/Shutterstock)

Zulu maidens dance during the memorial service for King Goodwill Zwelithini in Nongoma, South Africa, March 18, 2021. King Goodwill Zwelithini died on March 12, 2021 in the eastern city of Durban, aged 72, after weeks of treatment for a diabetes-related illness. (Photo by Phill Magakoe/Pool via Reuters)