As Russia suffers losses in Ukraine, President Vladimir Putin has made veiled threats to use nuclear weapons—a scenario that security experts still deem unlikely. WSJ looks at satellite images and documents to understand how the process of launching a strike would work. Photo composite: Eve Hartley More from the Wall Street Journal: Visit WSJ.com: http://www.wsj.com/ Visit the WSJ Video Center: https://wsj.com/video On Facebook: https://www.facebook.com/pg/wsj/videos/ On Twitter: https://twitter.com/WSJ On Snapchat: https://on.wsj.com/2ratjSM #Russia #NuclearWeapons #WSJ