Inside the effort to replace America's Minuteman III nuclear missiles

Cheyenne, Wyoming — Flying in over the Wyoming prairie aboard the Air Force's new Grey Wolf helicopter, the commanders of U.S. Strategic Command and Air Force Global Strike Command are taking us to a place that was once so highly secure that trespassers could be shot on sight — a Minuteman III Intercontinental Ballistic Missile, or ICBM, silo. Hundreds of these active nuclear silos dot the landscape from Colorado up to the Canadian border. "There are always approximately 400 (ICBMs) ready to go at any moment," says Air Force Global Strike Command General S. L. Davis over the Grey Wolf's comms system. CBS News traveled with Davis and Admiral Rich Correll, Commander of U.S. Strategic Command, for an exclusive look at the modernization of America's ground-based nuclear deterrent from the Minuteman III to the new Sentinel. They are leading the effort and are in Wyoming to inspect the progress at F. E. Warren Air Force Base in Cheyenne. L-R: Ian Lee aboard a Grey Wolf helicopter with the commanders of U.S. Strategic Command, Air Force Global Strike Command,General S.L. Davis and Admiral Rich Correll. CBS News We land at Echo 10 near the border with Colorado. It's the first silo to go offline as the Air Force shifts to Sentinel. But even for being a decommissioned silo, security is tight. An Air Force rapid response team, trained to retake nuclear silos from a hostile force, is already on the ground. Greeting us at the entrance is Colonel Terrance J. …