 Efforts to modernize the U.S. stockpile of ballistic missiles is coming at a much larger price. The Pentagon's plan to replace the Air Force's intercontinental ballistic missile fleet is now projected to cost 81% more than expected and will be delayed for a few years, according to top Pentagon officials. The new Sentinel ICBM will replace the 50-year-old Minuteman III's in America's nuclear arsenal, but it will now come with a price tag of close to $141 billion.