“Luna” drones promised by Germany to monitor the Russian-Ukrainian border may not be sent after all—they can’t handle the bitter cold expected in the Ukrainian winter. “It’s a technical problem of the Luna system that it can't be controlled reliably at temperatures below −19°C [−2°F],” German MP Gernot Erler told public broadcaster Deutsche Rundfunk. Winter temperatures in the region would often plunge far lower at the drones’ operational heights of 3,000 meters and above, Bild reported, citing a military source. German drones were supposed to join unmanned planes provided by France and Austria in the Organization for Security and Cooperation...