Russia appears to be preparing to test its new nuclear-armed, nuclear-powered cruise missile, according to two U.S. researchers and a Western security source, even as Russian President Vladimir Putin readies for talks on Ukraine with U.S. President Donald Trump on Friday. Jeffrey Lewis of the California-based Middlebury Institute of International Studies, and Decker Eveleth of the CNA research and analysis organization, based in Virginia, reached their assessments separately by studying imagery taken in recent weeks until Tuesday by Planet Labs, a commercial satellite firm. They agreed the photos showed extensive activity at the Pankovo test site on the Barents Sea...