A Ukrainian serviceman walks an empty street in the front line city of Bakhmut, in Donetsk region, Ukraine on February 25, 2023. (Photo by Serhii Nuzhnenko/Radio Free Europe/Radio Liberty)

Valentyna Konstantynovska, 79 years-old, holds a weapon during basic combat training for civilians, organized by the Special Forces Unit Azov, of Ukraine's National Guard, in Mariupol, Donetsk region, eastern Ukraine, Sunday, February 13, 2022. The United States is evacuating almost all of the staff from its embassy in Kyiv as Western intelligence officials warn that a Russian invasion of Ukraine is increasingly imminent. (Photo by Vadim Ghirda/AP Photo)

A young woman holds a weapon during a basic combat training for civilians, organized by the Special Forces Unit Azov, of Ukraine's National Guard, in Mariupol, Donetsk region, eastern Ukraine, Sunday, February 13, 2022. The United States is evacuating almost all of the staff from its embassy in Kyiv as Western intelligence officials warn that a Russian invasion of Ukraine is increasingly imminent. (Photo by Vadim Ghirda/AP Photo)

Servicewomen march during a rehearsal for the Independence Day military parade in central Kiev, Ukraine on August 20, 2018. (Photo by Gleb Garanich/Reuters)

A cat dressed in a traditional Ukrainian embroidered shirt takes part in a parade in Kiev, Ukraine on May 28, 2016. (Photo by Gleb Garanich/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)

A relative of a Chinese passenger aboard the Malaysia Airlines MH370, covers his face after being told the latest update in Beijing, China, Monday, March 24, 2014. A new analysis of satellite data indicates the missing Malaysia Airlines plane crashed into a remote corner of the Indian Ocean, Malaysian Prime Minister Najib Razak said Monday. The news is a major breakthrough in the unprecedented two-week struggle to find out what happened to Flight 370, which disappeared shortly after takeoff from Kuala Lumpur to Beijing with 239 passengers and crew aboard on March 8. (Photo by Ng Han Guan/AP Photo)

A containment shelter for the damaged fourth reactor (L) and the New Safe Confinement (NSC) structure (R) at the Chernobyl Nuclear Power Plant are seen from Ukraine's abandoned town of Pripyat, Ukraine, April 22, 2016. (Photo by Gleb Garanich/Reuters)