The attack was just hours away when Major Alan Johnson got the word Iran’s most powerful weapons were aiming for Al Asad.

Alan Johnson: My intelligence officer pulled me aside and basically said, “Sir, I’ve got some bad news for you.” “What’s up?” (LAUGH) “We have information that Iran is fueling 27 medium-range ballistic missiles and their intention is to level this base and we may not survive.”

Tim Garland: This is a completely different threat.

Lt. Col. Tim Garland commanded an Army battalion at Al Asad, a sprawling airbase about 120 miles west of Baghdad where the U.S. operated scores of helicopters, drones and other aircraft.

David Martin: Did the base have any defense against ballistic missiles?

Tim Garland: No sir. It was such an unprecedented threat. I don’t think it was ever calculated, so the capability to prevent a ballistic missile attack it– it wasn’t there.