An employee controls the arms of a manned biped walking robot “METHOD-2” during a demonstration in Gunpo, South Korea, December 27, 2016. It stands 13-feet (3,96 m) tall, weighs 1.3 tons and wields a pair of 286-pound (129,73 kg), motion-tracking metal arms. (Photo by Kim Hong-Ji/Reuters)

“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)

Axel, a research prototype rover for exploring the Moon, Mars and other planets, is remotely driven over rocks as engineers from Jet Propulsion (JPL) and grad students from Caltech (California Institute of Technology) demonstrate its mobile over the steep and rocky grounds of the JPL Mars Yard on January 14, 2009 in Pasadena, California. The rover is capable of descending cliffs or into craters and returning by a cable tethered to its starting point. Development of the Axel rover is a point effort funded by NASA Exploration Systems Mission Directorate (ESMD) and lead by Principal Investigator Issa Newnas and Co-Investigator and Caltech professor of mechanical engineering bio engineering Joel Burdick. (Photo by David McNew/Getty Images)

A prototype of a new nano spaceship is displayed during a press conference held by Israel's Space IL organisation on December 8, 2011 in Ehud, Israel. Israeli President Shimon Peres participated in the event unveiling Space IL's latest prototype nano spaceship with the aim of launching a Israeli robotic spacecraft that will land on the moon and raise funds for scientific education in Israel. (Photo by Ilia Yefimovich/Getty Images)

LOCOG Chair and former Olympian Lord Sebastian Coe holds a prototype design of the new golden Olympic Torch during its unveiling at St Pancras Station on June 8, 2011 in London, England. (Photo by Dan Kitwood/Getty Images)

Canoeists are framed by the tail of a breaching whale in Antarctica in April 2023. The photographer, from California, writes: “It was probably a once-in-a-lifetime moment”. (Photo by Jiahong Zeng/Solent News)

Barbadian singer Rihanna continues to rock her nostalgic look with her edgy short pixie cute while out with friends at Delilah Nightclub in West Hollywood on June 7, 2021. Rihana made sure to turn heads as she put on a sultry display in a black silk lingerie dress with a matching robe. (Photo by Backgrid USA)

Australian actress Elizabeth Debicki pictured as Princess Diana wearing her “Revenge Dress” at Vanity Fair's annual fundraising gala for the Serpentine Gallery while filming hit Netflix TV series “The Crown” in London, United Kingdom on November 1, 2021. The dress, created by Greek fashion designer Christina Stambolian, is one of the most famous dresses the late Princess wore. The form fitting, off-the-shoulder chiffon cocktail dress was worn in June 1994. The same night Diana wore the dress to the Serpentine party, her estranged husband, Prince Charles, confessed on national television that he had been unfaithful to her. (Photo by Splash News and Pictures)