A U.S.-led NATO exercise is underway this week in Poland, practicing the tactics to fend off an attack involving cruise and ballistic missiles, aircraft and drones. Called “Astral Knight,” it involves dozens of aircraft from the U.S. and Polish air forces as well as a U.S. Army Patriot missile battery. “It’s about putting the right force to defend against the right threat, in the right place at the right time,” Maj. Gen. Derek C. France, U.S. Air Forces in Europe’s director of operations, strategic deterrence and nuclear integration, said on Wednesday in a call with reporters. “If we do that, our operators will hit home runs all day long.”