In launching a new search for cures to what ails its nuclear missile corps, the Air Force is considering proposals it tried five years ago, according to internal emails and documents obtained by The Associated Press.

Many of the proposals fell short when they were tried before, but the new effort is more far-reaching, on a tighter timetable and backed by Defense Secretary Chuck Hagel. So it appears to hold more promise for an Air Force under scrutiny after a variety of embarrassing setbacks and missteps raised questions about whether some of the world’s most fearsome weapons are being properly managed.