Air Force officials insist that regardless of the cheating, there is no potential for a nuclear mistake because several backup procedures are in place. For their part, missile launch crew members say they do know the test material — which includes how to handle nuclear launch codes — but argue that the grading standards are unreasonably high.

Whoever is right, the cheating scandal comes as the nation’s missile launch officers, known as missileers, are caught in a vicious cycle. They work with the lethal jewels of the nation’s arsenal, for which errors can be catastrophic, but they find themselves forgotten on the sidelines, overshadowed by combat and Special Operations forces central to the marquee mission of fighting terrorism. No one wants a nuclear conflict, but many launch officers see their lot as spending a lifetime waiting for a war that will never come.

“The nuclear deterrent mission has lost much of its status in the Air Force as the Cold War ended, and many of the personnel on the mission are demoralized,” said Loren B. Thompson, the head of the Lexington Institute, a research organization.

Former missileers say the cheating is also driven by what they say are onerous consequences for failing the tests, including additional time on “alert” in the isolated, cramped underground capsules from which the missiles are launched.