The Air Force faces software design challenges for Northrop Grumman's [NOC] future LGM-35A Sentinel ICBM, according to the Government Accountability Office (GAO). "Sentinel is software-intensive, and development progress remains slower than anticipated,” says the new GAO two-page 'national security snapshot' on Sentinel. “These delays have raised concerns from program officials about the prime contractor’s ability to complete the program’s software in a timely manner. Software risks remain because, notwithstanding how long the program has been in development, the Air Force…