“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 serene turquoise glow glimmers from underneath these powerful icebergs. Stood in the middle of Antarctica, the giant icebergs appear to be from an unearthly world. These stunning photographs were captured by American photographer Michael Leggero. “My images show pure nature, as that is how I describe Antarctica, simply pure nature”, says the 43 year old, of Carthage, New York. “It is the only place on our planet that humans have not left a presence behind”. (Photo by Michael Leggero/Hotspotmedia/Visual Press Agency)

A man walks down a flooded road in Islip, New York August 13, 2014. More than a foot of rain hit parts of New York's Long Island on Wednesday, enough to set a preliminary state record, triggering flash floods and swamping cars on major roads that were turned into rivers during the morning rush hour. (Photo by Lucas Jackson/Reuters)

Parent hedgehogs Maria, left, and Gosha, 2nd right, eat with their albino babies in a private Zoo in Moscow, Russia, Thursday, August 22, 2013. Three rare albino hedgehog babies, born on the same day as Britain's new prince, have moved into a miniature castle at a Moscow petting zoo. The three are named after the Prince of Cambridge – George, Alexander and Louis. On Thursday, when they turned one month old, they were shown their new home at the All-Russia Exhibition Center. (Photo by Alexander Zemlianichenko Jr./AP Photo)

A woman takes selfie as municipal workers use cranes to lift carcass of Bryde whale at the Juhu beach, in Mumbai, India, Friday, January 29, 2016. Marine biologists in India were conducting an autopsy on the carcass of 35-foot long Bryde whale that washed ashore on a popular beach in the western city of Mumbai. The beached mammal which appeared to have died at sea two or three days ago was spotted on the beach Thursday by late evening walkers, who informed police. (Photo by Rajanish Kakade/AP Photo)

Anton Unitsyn, Russia. Shortlist, Professional , Daily Life. Parkour jumpers on their daily training. On the background – one of the main Solvychegodsk sights – Blagoveshchensky Cathedral. This church is among 3 churches, that survived soviet times. At the begining of 20th century there were 13 churches in Solvichegodsk. After breakdown of the communism, Solvichegodsk as many small towns in russia is stuck in it's past. Despite everything, people in Solvichegodsk still belive in their positive future, and wait for wind of change. (Photo by Anton Unitsyn/Sony World Photography Awards)

A four-day old African spurred tortoise, Geochelone sulcata, one of eight babies, was place on the head of its mother in their enclosure in Nyiregyhaza Animal Park in Nyiregyhaza, 226 km east of Budapest, Hungary, 27 September 2011. This was the first time that offspring of an African spurred tortoise were born in this zoo. The eight babies hatched after 115 days, they are 5.5 cms long and weigh 25 grams. Spurred tortoise is the largest species of land tortoises in Africa, the weight of an adult animal may reach 80 kgs. (Photo by Attila Balazs/EPA)

A child watching the sea while residents try to clear the bed of a river that has been blocked by debris left by Hurricane Matthew, in the commune of Roche-a-Bateaux, in the south west of Haiti, on October 21, 2016. At least 546 people were killed and more than 175,000 people lost their homes when Hurricane Matthew roared ashore on October 4, packing winds of 145 miles (230 kilometers) per hour. (Photo by Hector Retamal/AFP Photo)