“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 cat tries to find dry ground around an apartment complex in Houston after Hurricane Harvey hit on Aug. 30. Harvey made landfall in South Texas on August 25, leading to days of downpours that dumped more than 50 inches of rain. Harvey damaged or destroyed about 200,000 homes as the storm system flooded much of Houston and smaller coastal communities. (Photo by Scott Olson/Getty Images)

Lisandra Perez, 7, practices in his house before his flute lesson at the Integral System of Artistic Education for Social Inclusion (SIFAIS) center in the poor neighborhood of La Carpio, Costa Rica October 8, 2015. SIFAIS center is developing a social program with the help of 156 volunteers who teach art, music, sports and education, for children and youth living in La Carpio, known for being the home to gangs, violence, drugs and social vulnerability, according to the centre. (Photo by Juan Carlos Ulate/Reuters)

A long exposure image shows star trails from the abandoned submerged orthodox church of St. Nicholas without roof, submerged in the Mavrovo Lake, near Mavrovi Anovi, North Macedonia, 17 March 2019. Constructed in 1850 and submerged in 1952 due to the construction of the hydro system Mavrovo, the church St. Nicholas continues to attract the attention of almost every visitor as it peaks from the water. (Photo by Georgi Licovski/EPA/EFE)

A man rides his motorcycle along an empty street in Cali on April 17, 2021, during a curfew imposed by the government to help curb infections of the novel coronavirus, COVID-19, as weekend partial lockdown takes effect in four Colombian cities. In recent weeks, the Colombian government has imposed, and then tightened, a series of restrictions to stem a third wave of infections that is bringing its health system to the brink of collapse. (Photo by Luis Robayo/AFP Photo)

Girls practice sit-ups during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, on May 4, 2016. China's sports system has been enormously successful since the country returned to the Olympic fold in 1980, culminating with the host nation topping the medals' table at the 2008 Beijing Olympics. And yet, with the Rio de Janeiro Games less than three months away, the system is beginning to break down due to the shifting demographics of a more prosperous nation. (Photo by Aly Song/Reuters)

Humboldt Penguins swim in their pool as a keeper looks on through a spherical window during the annual stocktake press preview at London Zoo in Regents Park in London Monday, January 4, 2016. A requirement of ZSL London Zoo's license, the annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programmes for endangered animals. (Photo by Alastair Grant/AP Photo)