As an investigation continues into the cause of an engine malfunction during an October Delta IV launch, the head of Air Force Space Command said this week the service has pinpointed the problem as a fuel leak in the vehicle's combustion chamber. Gen. William Shelton told reporters at a Jan. 17 Defense Writers Group breakfast that the service is working to determine what caused the leak and has stalled all Delta IV launches until March 28. "We've gotten down to...