The Air Force's new ICBM is nearly ready to fly, but there’s nowhere to put it

DENVER—The US Air Force's new Sentinel intercontinental ballistic missile is on track for its first test flight next year, military officials reaffirmed this week.

But no one is ready to say when hundreds of new missile silos, dug from the windswept Great Plains, will be finished, how much they cost, or, for that matter, how many nuclear warheads each Sentinel missile could actually carry.

The LGM-35A Sentinel will replace the Air Force's Minuteman III fleet, in service since 1970...