“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)

In this April 12, 2015 photo, Sayed Ahmed Abdoh poles his boat to check his fish traps in the Nile River, near Abu al-Nasr village, about 770 kilometers (480 miles) south of Cairo, Egypt. Abdoh caught some 20 fish this day and gave them to his friend, Salama Osman, a migrant worker in a Cairo apartment building, to celebrate his biannual return to their village. (Photo by Hiro Komae/AP Photo)

A model jumps during a photo shooting, in Milan, Italy, Friday, January 15, 2016. Men's fashion week starts today and will run until Tuesday, January 19. (Photo by Luca Bruno/AP Photo)

Somali couple Mohamed Noor (L) and Huda Omar pose for a photograph at their makeshift home during their wedding ceremony in Mogadishu's Rajo camp, Somalia August 17, 2016. Having met two years ago, the pair have just married at Rajo camp, where some 400 families live. Most, like Noor's parents, came here in the early 1990s to flee famine. (Photo by Feisal Omar/Reuters)

A woman stumbes as people run down Oxford Street, London, Britain, November 24, 2017. Police are responding to reports of an incident at London's Oxford Circus Tube station and have urged the public to avoid the area. (Photo by Peter Nicholls/Reuters)

Visitors watch dinosaur models at Haitang Bay Rice Paddy Park on January 24, 2018 in Sanya, Hainan Province of China. The Haitang Bay Rice Paddy Park featuring 323 full-size dinosaur models was officially opened to the public on Thursday. (Photo by Yin Haiming/China News Service/VCG via Getty Images)

Animal rights activists perform, demanding the abolition of bullfights, during a demonstration in Medellin, Colombia February 11, 2018. The Colombian Constitutional Court overruled on February 7, 2018, a judgment that allowed to hold a referendum regarding bullfights. (Photo by Fredy Builes/Reuters)

Fikiri Kiponda, left, and Wilson Saro, right, carry a green turtle that was unintentionally caught in a fisherman's net, before releasing it back into the Watamu National Marine Park on the Indian Ocean coast of Kenya Wednesday, September 22, 2021. A former accountant, Kiponda and the Local Ocean Conservation group rescue sea turtles that have been caught in fishermen's nets, and then release them back into the marine park or treat injured ones at a rescue center until they are fit. (Photo by Brian Inganga/AP Photo)